Summary and Conclusions
Composting is a cost effective and environmentally sound alternative for the stabilization and ultimate disposal of wastewater sludge. It produces compost a stable, humuslike material which is a soil conditioner. Thus, the process can achieve waste treatment with resource recovery and represents a beneficial use of sludge. Recent advances have been made in the basic fundamental science associated with composting along with the technology used for the process. These advances have increased the...
Physical And Psychological Benefits Of Going Barefoot
For thousands of years humans lived in close connection with the Earth they walked and ran barefoot. They slept on the ground. In modern times our lifestyles have more or less totally disconnected us from our planet. However, barefoot walking and running have apparent benefits for our mind and body, and activities like natural running are making a comeback.
DIY Wind Turbine Guide: Finding the Perfect Motor
When it comes to building a DIY wind turbine, choosing the right motor is essential for optimal performance and efficiency. A suitable motor can make a significant difference in the power output and overall effectiveness of your homemade wind turbine. By carefully considering these factors and the type of motor, you can build a highly efficient and effective DIY wind turbine that meets your energy needs.
Per hour Electricity used by an Air Cooler
One of the main concerns of homeowners during summers is the rise in electricity bills caused by indoor cooling devices like air coolers and air conditioners. When it comes to electricity use, air coolers are much more efficient than air conditioners. But how much can you save with an air cooler Let's find out. Power consumption of air cooler in comparison to air conditioners Most branded air coolers come with a power rating between 125W to 230W.
Dispersal dispersion and distribution
7.1 Introduction This chapter explores some of the reasons why populations are found where they are. We describe the finer-scaled pattern as the dispersion and the broader scale as the distribution. We offer examples of how different factors such as temperature and seasonality limit the distribution of wildlife. We then discuss the causes for dispersal, and finally methods of modeling rates of dispersal of populations. Dispersal is the movement an individual animal makes from its place of birth...
What is population regulation
One of the problems with this debate is a lack of agreement as to what a regulated population is. Given what we learned in the previous two chapters about the behavior of populations with time lags, with high reproductive potentials, or under the influence of demographic and environmental stochasticity, it is not realistic to expect a population to show a simple attraction to a specific number called the carrying capacity. In Chapter 2 we defined a stable point as a stable number at the...
Mechanisms Of Sound Production
As Henry (Chapter 10) emphasises here, insects are preadapted to be noisy animals. With a hard and sclerotised exoskeleton, the segmented form of the body and jointed limbs will inevitably cause vibrations in the surrounding environment when an insect moves. It will be very difficult for insects to move silently without making a noise. It is not surprising that many groups have developed specialised systems of sound production and associated receptors which are used in communication within and...
Amazon dam project pits Brazil's quest for renewable energy against environmental and indigenous rights
Plans for the construction of a massive hydroelectric dam in the Brazilian Amazon have experienced some recent setbacks in the form of back and forth legal action as well as controversy over indigenous rights and environmental issues. As of Friday, however, bids for construction contracts are again set to move forward on the previously planned date of April 20th.
Evenness or Equitability
Three measures of diversity that have been widely used in ecology are Simpson's index, Shannon's entropy, and the total number of species or species richness. Some species diversity indices are based on the concept of evenness or equitability. Simply put, the concept of evenness refers to the extent to which each species is represented among the sample. The extremes would range from one species being dominant and all other species being present in very low numbers (one individual for each...
SeaWorld Killer Whale Lives Up to its Name; Attacks and Kills Trainer
Living in captivity is not all it's cracked up to be. Imagine bright flashing lights, being confined to the same small tank day in and day out, and having to perform ridiculous tricks for the entertainment of others. All you get out of it is some stinking fish. Yeah, I'd feel like I got a pretty raw deal, too. Tilikum the killer whale seems to feel the same way. Yesterday, Tilikum attacked and killed a trainer at the Orlando-based SeaWorld.
The Imperative of Early Dog Training: Building Bonds and Ensuring Safety
Welcoming a dog into one's home isn't just an addition of a pet it's an expansion of the family. These sentient beings, characterized by their loyalty, intelligence, and capacity for affection, are more than just four-legged creatures. They become our companions, our guardians in the dark of the night, and our partners in the simple joys of life. Yet, just as the joy and companionship they bring are profound, so is the responsibility we hold towards them.
Theories to Explain High Diversity in the Tropics
The question, Why are there so many species in the tropics is one that has intrigued scientists for almost a century. Scores of theories have been put forth to account for the increase in diversity in almost all taxa along a gradient of decreasing latitude. Pianka (1966) reviewed the major theories of the time and lumped them into six categories the time theory the theory of climatic stability the theory of spatial heterogeneity the competition hypothesis the predation hypothesis and the...
What Do Snapping Turtles Eat?
This article is all about the diet snapping turtles eat in the wild and captivity as pets as an answer to the common question what do snapping turtles eat. You will also learn the basics of caring for snapping turtles as pets at home. What do snapping turtles eat Snapping turtles eat both plants and animal meat because they are omnivorous.
What Do Turtles Eat? Facts About Feeding A Turtle
There are hundreds of species of turtles all across the world. While some turtle species are appropriate to be reared as pets, others can grow very large and weigh up to several hundreds of kilograms This article aims to discuss common fresh water and sea turtles and the types of foods they love to eat both in the wild and in captivity.
Natural selection
In the previous sections we have been looking at some of the ways in which non-adaptive processes can affect the genetic variation of populations. Genetic diversity is affected also by natural selection, a process that leads to 'the differential reproduction of genetically distinct individuals or genotypes within a population' (Li, 1997). Natural selection can alter allele frequencies in a number of different ways that can either increase or decrease overall genetic variation. Both stabilizing...
What Do Sugar Gliders Eat: Feeding A Pet Sugar Glider
The sugar glider, named scientifically as Petaurus breviceps is a quite popular pet nowadays. Sugar gliders acquired their name because these cute and playful animals love sipping nectar and sweet tree sap in its natural habitat. Because of its minute size and cute appearance, sugar gliders make a popular exotic animal that has been sold and reared as pets.
What Do Kangaroos Eat? The Feeding Of The Famous Australian Animal
We think it's safe to say that all of us know what kangaroos are. Kangaroos have been portrayed on television and in films as big, brown animals who carry their young in their pouches. Which is true for this marsupial from the Macropods family, for they do have pouches in their tummies where they put their babies in but there's more interesting things that one has to know about them. For one, the word Kangaroo is from gangurru, a Guugu Yimithirr word.
The Competitive Exclusion Principle
Figure 8.9a and b describes cases in which a strong interspecific competitor invariably outcompetes a weak interspecific competitor. It is useful to consider this situation from the point of view of niche theory see Sections 2.2 and 3.8 . Recall that the niche of a species in the absence of competition from other species is its fundamental niche defined by the combination of conditions and resources that allow the species to maintain a viable population . In the presence of competitors,...
Monocrop Farming: Green Revolution or environmental blunder of historic proportions?
While writing about Colony Collapse Disorder (the disappearance of the world's honeybee population) I came across an article by Canadian investigative journalist Alex Roslin about monocrops and their detrimental effects on world hunger, biodiversity, nutrition, food supplies, water toxicity and soil quality.
Nematodes phylum Nemathelminthes Nematoda
There are 20,000 morphotypes of free-living interstitial nematodes that are found in terrestrial habitats and along a continuous gradient, into the deep-sea sediments. Many more species remain to be described, particularly from marine sediments. To these we must add about 2000 plant parasites, that can devastate agricultural productions. Nematodes are ubiquitous in soils and are an integral component of decomposition ecology. For general reference on nematode structure and function, students...
What Do Badgers Eat?
This article will answer the question what do badgers eat. We will also show you some cool facts about badgers that will surely surprise you. Who doesn't love badgers They are among the cutest and most recognizable creatures in the animal kingdom. They are so iconic that countries like Great Britain consider them a part of their National Heritage. But while these creatures are fascinating, they are also shrouded in mystery especially when it comes to their diet.
Dispersal and colonization
The ability of a population to persist in the long term depends on the balance of reproduction and mortality. The early representatives of a species must first of all be able to populate a particular habitat. This colonization can result from active movement or from passive transport. Many organisms have special dispersal stages that are especially well suited to being transported. One can view lakes as islands that are separated from one another by a completely different habitat. Even when...
Acidification Processes in Soil and Bedrock
An acid is a compound which has the capability to release H ions Box 1 . High concentrations of H low pH values can attack natural materials such as limestone, soil minerals, and living tissues or man-made materials or artwork such as cement, concrete, metal surfaces, or sculptures. Acidification of soils is a natural process on geological timescales. In general, soil acidification can be described as a two-step process 1. The slow gradual depletion of nutrient cations, that is, the leaching of...
Industrial Revolution Industrialization
The transformation from an agricultural to an industrial society began only about 250 years ago, but its consequences for the natural world are almost unprecedented. The major innovation that marks the industrial era is the exploitation of the earth's vast stocks of fossil fuel. The availability of more energy per capita has led to undreamed of material wealth for a significant percentage of the world's population, but it has also put tremendous pressure on land and natural resources. The major...
What do Cougars Eat?
A cougar is a North American sandy colored puma. They are sometimes known as Mountain Lions. Cougars are mostly nocturnal animals, searching for food and hunting during the night, although they have been known to move around in the daytime too. They are solitary animals, that spend much of their lives on their own. What do cougars eat in the wild What do cougars eat are generally grazing creatures such as deer, elk, mountain goats, moose, and wild sheep.
Kalundborg As A Model The Kalundborg Complex Historical Evolution
A highly evolved industrial symbiosis is located in the seaside industrial town of Kalundborg, Denmark (Gertler and Ehrenfeld 1996). Some 18 physical linkages comprise much of the tangible aspect of industrial symbiosis in Kalundborg (see Figure 27.2). The six key local players in the network that has developed are Asnaes Power Station, SK Power's 1350-megawatt power plant a large oil refinery operated by Statoil A S Novo Nordisk Novozymes A S, a Danish pharmaceutical and a Danish biotechnology...
What Do Emperor Penguins Eat?
This article will answer the question what do emperor penguins eat both in the wild and in captivity. It will also show you some remarkable facts about this wonderful bird species. sc name adsense The Emperor Penguin (Aptenodytes forsteri) is the tallest and biggest of all known species of penguins and is native to Antarctica. Emperor penguins are amazing creatures. They have a white stomach, a black head and black tail, backs and wings.
The Evolutionary Origins Of The Weasels
Weasels belong to the canoid group of placental carnivores, which originated in the New World (Flynn & Wesley-Hunt 2005). The first predatory mammals with characteristics of the weasel family, and clearly different from their closest relatives the Procyonids (Bininda-Edmonds et al. 1999), appeared in North America in the early Miocene, some 28 to 30 million years ago (Figure 1.4). Throughout the Miocene period, these animals were forest-dwelling hunters, probably somewhat like martens. Some...
Autochthonous and allochthonous production
All biotic communities depend on a supply of energy for their activities. In most terrestrial systems this is contributed in situ by the photosynthesis of green plants - this is autochthonous production. Exceptions exist, however, particularly where colonial animals deposit feces derived from food consumed at a distance from the colony e.g. bat colonies in caves, seabirds on coastland - guano is an example of allochthonous organic matter dead organic material formed outside the ecosystem . In...
The type 2 functional response
The most frequently observed functional response is the 'type 2' response, in which consumption rate rises with prey density, but gradually decelerates until a plateau is reached at which consumption rate remains constant irrespective of prey density. (Realistically, even a type 1 response must have a plateau, as in the example above. The distinction is between the deceleration of a type 2 response and the linearity of the type 1 response.) Type 2 responses are shown for a carnivore, a...
The diversity of parasites
The language and jargon used by plant pathologists and animal parasitologists are often very different, and there are important differences in the ways in which animals and plants serve as habitats for parasites, and in the way they respond to infection. But for the ecologist, the differences are less striking than the resemblances, and we therefore deal with the two together. One distinction that is useful, though, is that between microparasites and macroparasites (Figure 12.1) (May &...
The population dynamics of small populations
Much of conservation biology is a crisis discipline. Managers are inevitably confronted with too many problems and too few resources. Should they focus attention on the various forces that bring species to extinction and attempt to persuade governments to act to reduce their prevalence or should they restrict activities to identifying areas of high species richness where reserves can be set up and protected see Section 22.4 or should they identify species at most risk of extinction and work out...
Detritivores and specialist microbivores
The microbivores are a group of animals that operate alongside the detritivores, and which can be difficult to distinguish from them. The name microbivore is reserved for the minute animals that specialize at feeding on microflora, and are able to ingest bacteria or fungi but exclude detritus from their guts. Exploitation of the two major groups of microflora requires quite different feeding techniques, principally because of differences in growth form. Bacteria and yeasts show a colonial...
The importance of transfer efficiencies in determining energy pathways
The proportions of net primary production that flow along each of the possible energy pathways depend on transfer efficiencies in the way energy is used and passed from one step to the next. A knowledge of the values ofjust three categories of transfer efficiency is all that is required to predict the pattern of energy flow. These are consumption efficiency CE assimilation efficiency AE and production efficiency PE . the relative importance of energy pathways depends on three transfer...
Unitary and modular organisms
Our 'ecological fact of life', though, implies by default that all individuals are alike, which is patently false on a number of counts. First, almost all species pass through a number of stages in their life cycle insects metamorphose from eggs to larvae, sometimes to pupae, and then to adults plants pass from seeds to seedlings to photosynthesizing adults and so on. The different stages are likely to be influenced by different factors and to have different rates of migration, death and of...
Variations in the intensity and quality of radiation
A major reason why plants seldom achieve their intrinsic photosynthetic capacity is that the intensity of radiation varies continually Figure 3.3 . Plant morphology and physiology that are optimal for photosynthesis at one intensity of radiation will usually be inappropriate at another. In terrestrial habitats, leaves live in a radiation regime that varies throughout the day and the year, and they live in an environment of other leaves that modifies the quantity and quality of radiation...
Hardy Weinberg equilibrium
Under certain conditions, the genotype frequencies within a given population will follow a predictable pattern. To illustrate this point, we will use the example of the scarlet tiger moth Panaxia dominula. In this species a one locus two allele system generates three alternative wing patterns that vary in the amount of white spotting on the black forewings and in the amount of black marking on the predominantly red hindwings. Since these patterns correspond to homozygous dominant, heterozygous...
The woodland ecosystem food chains food webs and the plant animal and decomposition subsystems
Trees dominate the woodland and forest communities in which they grow but hosts of other organisms - including fungi and bacteria - which evolved in parallel with them, live beside, beneath and in them in an interacting whole. The types of animals involved in such communities are illustrated in Fig. 1.8 in many other parts of the world the major differences from western European forests involve the presence of much larger herbivores and carnivores and of primates such as monkeys and gorillas....
The Problem of Black Tipped Tails
One of the curious quirks of research, and the salvation of many a graduate student, is that it is possible to design a study to ask one question and then be led to a valid answer to a different question. Powell's convictions about the effect of raptor predation on the numbers of weasels in ecological time stimulated him to design a series of simple, elegant experiments with trained red-tailed hawks. They produced a legitimate answer to a long outstanding question in a different field...
From Birth to the Opening of the Eyes
Infant weasels look rather alike in all species, both in their appearance at birth and in their early physical development. They are all born completely helpless, and all grow in the same way, but least and common weasels develop more rapidly than do stoats and longtails, and they reach the milestones of development at younger ages Table 9.3 . For example, although young stoats and longtails are born larger than young common weasels, they grow more slowly, and are 6 to 8 weeks old before they...
The Skeleton
Everything about a weasel is attuned to the profession of hunting for small prey in dark, confined spaces. In motion, weasels appear almost boneless. We have seen weasels leap into a hole and then look out again in a single, fluid action so fast that the tail was not in before the nose came out again. A weasel can do this because the articulations between its vertebrae are so flexible that it can turn over and walk back over its own hindquarters. Living and working in tunnels are normal and...
The Pattern and Timing of the Molt
A complete molt cycle lasts from the beginning of the active phase of the follicles to the end of the shedding of the old fur. Since these are quite separate processes, even in one follicle, the cycles of growth and shedding can overlap. The biology of weasels offers two quite different methods of working out the timing and length of the cycle, depending on the species and location. In places where weasels reliably turn white in winter, the simplest technique is to arrange a set of skins...
Pauropus Silvaticus
Vertical distribution of astigmatic mites in conventional and no-tillage agroecosystems. Arrows indicate autumn and spring dates for mowing, tillage, and planting. Numbers increased under conventional tillage following autumn tillage, but not following spring tillage (from Perdue and Crossley, 1990). described a buildup of astigmatic mites following pipeline construction in Ontario, Canada. The mites were associated with accumulations of residue under moist conditions. Philips...
Mating Behavior In Adults
Mating is a very vigorous affair in all weasels. It has to be, because the stimulus of copulation is needed before ova can be released. All attempts to stimulate ovulation by injection of gonadotropins, the hormones that usually have this effect in other animals, have failed Rowlands 1972 Gulamhusein amp Thawley 1974 , and the ovaries of unmated females have no corpora lutea. Females are subordinate to males for most of the year, and normally avoid them, but a female is well able to reject...
Age span of reproduction and birth rates
Puberty is generally taken as the onset of the first estrous cycle in the female and the production of viable sperm in the male. Sexual maturity is the age at first ovulation in the female and the presence of a dense mass of motile sperm in the male. In both sexes, there may be a difference of 2-4 years between puberty and sexual maturity among elephants. Although there is tremendous variation across elephant populations in the age of sexual maturity, the early East African studies showed that...
Causes of death and mortality rates
The causes of death and the mortality rates are notoriously difficult to estimate for most wild mammalian species, including the elephant. Carcasses in the field are usually putrefied, making it difficult to identify the cause of death, especially if a pathogen is involved. Juveniles in the population are usually under-represented in a collection of remains discovered thus, estimation of age-specific mortality rates for the younger age classes, vital for understanding population dynamics,...
How many species and subspecies of elephants are there
The molecular data from both Asian and African elephant populations, although still in early analysis, are already threatening to overturn the traditional systems of classification. At our present level of understanding of the genetics of Asian elephants, there is no support for the subspecies status of the Sri Lankan elephant population (Elephas m. maximus) and its differentiation from those in mainland Asia (E. m. indicus). These studies and unpublished data clearly indicate that several...
Physiology of the female reproductive cycle
As in other mammals, the reproductive tract in female elephants is composed of a pair of ovaries (located near the kidneys), the Fallopian tubes, a uterus with two cornua or horns, and a chamber that leads into the urogenital passage that opens externally at the vulva. A striking feature of the reproductive system in elephants is the long (nearly 1 m) urogenital canal, a common passage for both the genital and urinary tracts that opens at a position anterior to the hind legs. The clitoris is...
Competition between Paramecium species
The fourth example comes from the classic work of the great Russian ecologist G. F. Gause, who studied competition in laboratory experiments using three species of the protozoan Paramecium (Gause, 1934, 1935). All three species grew well alone, reaching stable carrying capacities in tubes of liquid medium. There, Paramecium consumed bacteria or yeast cells, which themselves lived on regularly replenished oatmeal (Figure 8.3a). When Gause grew P. aurelia and P. caudatum together, P. caudatum...
Box 211 Techniques Used To Collect Preserve And Investigate Octocoral Colonies
When taxonomic identification is attempted, a photograph showing the entire colony and its growth form is advantageous, and close-ups of details of the surface and polyp structures are useful for reference. Although with practice it is possible to identify a number of octocorals to genus level underwater or from photographs, it is rare that they can be identified to species level because a compound microscope is needed to investigate sclerites in detail. Most soft corals have different...
What Do Panthers Eat?
A black panther is not a species in its own right the name black panther is an umbrella term that refers to any big cat with a black coat. When a big cat is completely black, it is called melanism'. Melanism is the opposite of albinism. Black Panthers in Asia and Africa are actually leopards, whilst black panthers in the Americas are, in fact, Jaguars.
What Do Llamas Eat?
Llamas belong to the same family as camels and are classed as Camelidae. They do not have humps to store fat, but like camels, they can go for long periods of time without drinking water. Llamas live in the wild, and as domesticated animals reared on farms, in zoos, and as pets. What do llamas eat can really depend on where they are raised. What do llamas eat Llamas are usually fed grains, grass hay, and herbivore pellets.
Germination
The seeds of such aquatic plants as Echinodorus and Sagit-taria readily take up water and swell quickly because they do nof possess hard and impervious outer coatings. They germinate very readily and quickly. In other genera the seeds are firm and hard, germinating only after a long immersion during which bacteria and other organisms have time to weaken or dissolve the waterproof outer coating. The seeds of Potamoget n, for example, require a 'fermentation' process in marshy conditions. In...
Tests of density dependence
How can we detect density dependence in the field For a density-independent population, Tanner (1966) proposed that we can simply use the equation for discrete growth, Nt+1 XNt. After taking natural logs of both sides of the equation we can write When we plot ln Nt+1 versus ln Nt, if X is a constant, we should have a straight line with the slope of 1.0 and a y-intercept equal to ln X r. But if there is density dependence and the growth rate slows with population size, when ln Nt+1 is graphed...
What Do Weasels Eat?
This article will answer common questions regarding the weasel's unique diet such as what do weasels eat or can I have a weasel as a pet What do weasels eat Weasels are carnivores, that will usually only eat other animals. They usually hunt prey that are smaller than themselves, such as rats, voles, shrews, chipmunks, mice, and other small mammals. Weasels are also known to prey on animals larger than themselves too, like rabbits and hares.
The Global Inventory of Microbial Diversity and the Great Plate Count Anomaly
Cellular microorganisms can be categorized based on their cell morphology and ultrastructure into two groups, namely the prokaryotes Bacteria and Archaea and the microbial eukaryotes Eukarya . However, it is important to emphasize that 'prokaryotes' do not represent a coherent evolutionary grouping. The term prokaryote is, however, a useful and pragmatic shorthand that is widely used to describe members of the Bacteria and Archaea which are as evolutionarily distinct from each other as they are...
The Reproductive Anatomy Of Weasels
The testes of males are simple oval sacs within the furry scrotum. The coiled tube of the vas deferens leaves the epididymis, at the distal end of the testis, and ascends back into the body cavity again. The penis is stiffened by the baculum, a small rod-shaped bone attached to the pelvis by muscles at one end, which acts as a rigid support during copulation. The urethra fits within a groove on the underside of the baculum, shown in Figure 9.1. Normally the whole apparatus is hidden inside the...
What Do Crawfish Eat?
What do crawfish eat Let's learn the food types that this favorite sea food eats before we eat them. Crawfish, also called crayfish, freshwater lobsters, crawdads, yabbies, mudbugs or mountain lobsters are freshwater crustaceans that are similar to small lobsters, in which they have some relation. Just like lobsters, they have pincers and are colored brown, gray and red. They are members of the family Parastacoidea and family Astacoidea. Crawfish breathe through feather-like gills.
Genetic causes of extinction
Genetic factors leading to extinction include evolutionary changes in small populations. If a species with a small surviving population is in close proximity to more abundant congeners with which it can interbreed, a real Fig. 13.6 Extinction via hybridization. Here a rare species (white circles) has its range surrounded by another species (black circles) with which it can hybridize, reducing its ability to replace itself. Interbreeding occurs with close-neighbours, and eventually, all the...
Somatic maintenance
Ingested sugars, following eventual absorption (as monosaccharides) into the bloodstream via the gut, can be used immediately for maintenance or they can be converted, for subsequent use, to either of two types of carbohydrate reserve trehalose or glycogen. Trehalose comprises two linked glucose molecules. It is present in tissues (e.g. musculature) but occurs mainly in the blood, and so is known by many physiologists as the 'insect blood sugar' (Blum 1985, Thompson 2003). However, whereas...
Mac Arthur and Wilson and the equilibrium theory
Spatial ecology has its roots in the MacArthur and Wilson equilibrium (or dynamic) theory of island biogeography. MacArthur and Wilson (1963, 1967) brought a quantitative theoretical framework to the study of biogeography. Even before Darwin carried out his pioneering work on the Galapagos, islands and island examples have been of great importance in biology, and islands have been analyzed as natural laboratories and experimental systems. They are small, contained ecosystems in which certain...
Suspension Feeders
B T Hentschel, San Diego State University, San Diego, CA, USA J Shimeta, University of Melbourne, Parkville, VIC, Australia 2008 Elsevier B.V. All rights reserved. What Is Suspension Feeding Organisms That Suspension Feed Mechanisms of Particle Contact Retaining Contacted Particles Suspension Feeding in More Complicated Flow Regimes Ecological Interactions Related to Suspension Feeding Further Reading Suspension feeding is the capture and ingestion of food particles that are suspended in water....
Salinization
This describes the situation where total dissolved ions, and thus salts, are high, often because of human activities. Salinization refers to either the process or the result of the buildup of dissolved salts in fresh waters. The natural range of salinity in inland waters is considerable, but when referring to the result of human activities, we often are concerned with changes from relatively low background concentrations. Using a world average of 120 mg L 1 for reference (Table 4.
Resourcebased competition theory
David Tilman (1976, 1987) and others pointed out that the Lotka-Volterra equations were phenomenological and not mechanistic. That is, competition coefficients were merely measures of the effect of one species on the growth rate of another. They are estimated from experiments in which two species are grown together. Therefore they are not an independently derived value that allows one to predict coexistence or competitive exclusion, or, in the latter case, which of two species should win....
Time lags and limit cycles
Assumption 4 of the logistic equation, in which populations are assumed to respond immediately to carrying capacity, is highly unlikely for populations with great reproductive potential. In order to explore this possibility, we can introduce a lag time effect into the logistic equation. Using the discrete time form of the logistic (Eqn. 2.1), substituting X for R, and remembering that X er, Equation 2.12 is an equivalent to Equations 2.1 and 2.10c. To introduce time lags, Equation 2.14 is...
Competition between bedstraws Galium spp
Tansley, one of the greatest of the 'founding fathers' of plant ecology, studied competition between two species of bedstraw (Tansley, 1917). Galium hercynicum is a species which grows naturally in Great Britain at acidic sites, whilst G. pumilum is confined to more calcareous soils. Tansley found in experiments that as long as he grew them alone, both species would thrive on both the acidic soil from a G. hercynicum site and the calcareous soil from a G. pumilum site. Yet, if the species...
Interspecific competition early experiments and the competitive exclusion principle
Early in the twentieth century, Tansley (1917) experimentally demonstrated the potential power of interspecific competition in shaping ecological communities. Tansley had observed that closely related plant species living in the same region were often found in different habitats or different soil types. For his experiment he selected two species of an herbaceous perennial, bedstraw, in the genus Galium (Rubiaceae). One species, G. saxatile, is normally found on peaty, acidic soils, while the...
The Levins or classical metapopulation
According to the Levins model, metapopulation persistence is due to a stochastic balance between local extinction and re-colonization of empty habitat patches. The rate of change in occupied habitat patches is a function of colonization rates (c) and extinction rates (e) as shown in Equation 5.2 (Levins 1969). P is the proportion of patches occupied by the population under consideration. As described by Hanski (2001), if we define P' as the number of habitat fragments occupied by the species...
What Do Arctic Foxes Eat?
What do arctic foxes eat The Arctic fox, sometimes known as the snow fox, polar fox or white fox, are both hunters and opportunistic feeders. This article aims to discuss information regarding the arctic foxes diet in detail. What do arctic foxes eat Arctic foxes are predators so they hunt small rodents such as lemmings. Arctic foxes also eat insects, birds, eggs, and fish.
Patterns of Succession
Two types of succession can be recognized. Primary succession occurs on newly exposed substrates (e.g., lava flows, uplifted marine deposits, dunes, newly deposited beaches, etc.). Primary succession usually involves a long period of soil formation and colonization by species requiring little substrate modification. Secondary succession occurs on sites where the previous community was disturbed and is influenced by remnant substrate and surviving individuals. Although most studies of succession...
What Do Gorillas Eat? Feeding Habits Of A Gorilla
As far as population genetics is concerned, gorillas are considered by scientists as one of the few species of great apes that are closely related to humans. What are great apes by the way What are their differences with monkeys Great apes are monkey relatives but they differ in size, posture, the presence of tails and size of brains. Great apes which include gorillas are larger in size. They are able to walk upright for hours.
Teleology and extreme principles a tentative Fourth Law of Thermodynamics
All is for the best in the best of all possible worlds. Teleology is a lady no biologist can live without, but whose company seems shameful It does not seem that we are living in an ordered world, and nature is not an exception to this, but we wish to live in such a world, which is close to the Hellenistic one. Its Aristotelian philosophy of life was teleological and deterministic in principle a different form of philosophy was scarcely thinkable in the well-ordered Graeco-Roman society in its...
Reptilian Ancestors
Although no definitive fossils have been found of the amphibian ancestors from which the reptiles evolved, they are usually considered to have been an early egg-laying offshoot of an amphibian group (Batrachosauria) of which Seymouria (Fig. 4) is an example. Seymouria, Solenodonsaurus and the larger Diadectes (Fig. 4) have sometimes been classified as basal reptiles - but the point at which reptilian characters dominated over those of amphibians is unclear. The remnants of lateral lines on the...
Biophysics Of Sound Production And Acoustic Behaviour
In insects, sound or vibration is usually produced by the friction of two body parts moving across one another (Ewing, 1989). This event is termed stridulation. Stridulation using the forewings is widespread in Orthoptera of the suborder Ensifera. Bushcrickets produce sound (and vibration) signals by elytro-elytral stridulation. During evolution they have developed two specialised (asymmetrical) regions on their forewings used for sound production. The right elytron bears a FIGURE 3.16...
Stridulatory Organs
All stridulatory organs share the same basic structure consisting of two parts moving against each other a usually elevated pars stridens with fine parallel ribs and a plectrum, which is essentially a sharply confined ridge moving across the pars stridens. In some cases this distinction is hard to make, however, as both parts may be ribbed and barely distinguishable. The terminology used to describe the various stridulatory organs is based upon the location of the part regarded as the pars...
Recording Devices Hearing And Behaviour
Pierce (1948) published one of the first comprehensive attempts, known to me, to record and analyse insect songs in a systematic manner. None of the equipment which we now take for granted, with the exception of the microphones, was then available to him. He manufactured a number of ingenious devices for recording and analysing calls, but his results are now of little more than historical interest. All of the insects that Pierce described produced loud, airborne, acoustic signals and were...
Lineage sorting
The contrasting phylogenetic patterns in reproductively isolated populations in Figure 5.10 assume that the populations are genetically distinct from one another, but this is not always the case because when two populations first become isolated from one another they may both harbour copies of the same ancestral alleles. Over time, they will go through a process known as stochastic lineage sorting (Avise et al., 1983), which must occur before alleles become population-specific. Lineage sorting...
Water Uptake in Deserts Animals
Vertebrates are able to obtain water from three sources 1 free water, 2 moisture contained in food, and 3 metabolic water formed during the process of cellular respiration. Some are able to receive water from all three sources, while others are able to exploit only one or two methods. Highly mobile animals tend to be restricted to the use of open water sources that are often sparse and far between. Typical examples are desert birds that fly in regular intervals to the few bodies of water...
How Can Future Oil Spills Be Prevented
Over the last several decades, there have been a number of headline making oil spills that have left the world with shocking images. We have seen the results of drilling in the ocean floors to find oil. We know that our dependency on fossil fuels drives an industry that requires destroying some of our most precious resources.
Behavioral characteristics of musth
The elephant's temporal glands are a pair of modified sweat glands located on each side of the head between the eye and the ear. The onset of musth can be seen from swelling of the temporal glands and the secretion of fluid (the musth fluid), which streams down the cheeks of the animal (fig. 3.4). There are different stages in the manifestation of musth. Toke Gale describes four stages of musth based on his observations of Burmese timber elephants. Based on this description and other...
Inbreeding depression
Inbreeding is more likely to occur in small populations simply because there is a greater chance that an individual will mate with a relative. In a diploid species, inbreeding increases the likelihood that an individual will have two alleles that are identical by descent at any given locus, and it therefore has the effect of increasing homozygosity at all loci. For this reason, the inbreeding coefficient F is based on heterozygosity deficits (Equation 3.15). This relationship between inbreeding...
Genetic drift
Genetic drift is a process that causes a population's allele frequencies to change from one generation to the next simply as a result of chance. This happens because reproductive success within a population is variable, with some individuals producing more offspring than others. As a result, not all alleles will be reproduced to the same extent, and therefore allele frequencies will fluctuate from one generation to the next. Because genetic drift alters allele frequencies in a purely random...
Codominant markers
In a diploid species, each dominant marker will identify one allele in a homozygous individual and two alleles in a heterozygous individual (Figure 2.4). This ability to distinguish between homozygotes and heterozygotes is one of the most important features of co-dominant markers because it means that we can calculate easily the allele frequencies for pooled samples (such as populations). Allele frequency simply refers to the frequency of any given allele within a population, i.e. it tells us...
Predator Switching
In the North Pacific Ocean, populations of seals, sea lions, and sea otters have sequentially collapsed over the last several decades (Springer et al. 2003). Scientists initially thought that physical changes in the ocean or competition with fisheries were to blame, but it now appears that killer whales are responsible. Killer whales usually consume great whales (such as sperm whales and bowhead whales), but great whale numbers were significantly decreased after World War II by human whaling....
Energy Storage and Expenditure
The snow creaks under our winter boots as we walk along the snow scooter track to our study site. The cold is overwhelming, and though we have been walking for an hour, we do not feel warm. The air is perfectly still, and the heavy snow on the branches of the surrounding conifers absorbs all sounds. When we arrive at the bait station, we spill some seeds onto the feeding tray and retire to the nearby trees. The seeds soon attract the attention of some willow tits. It is astonishing that these...
The Hippocampus
Many ofthe cognitive processes involved in foraging, including spatial memory, working memory, episodic and declarative memory, the formation of complex associations, and the integration of experience over time, to name Neuroscientists are striving to identify the neural circuitry that processes rewards and to determine its role in learning, prediction of future consequences, choice between competing options, and control of ongoing actions. The following examples illustrate neuroscientific...
Nematode Feeding Habits
Nematodes feed on a wide range of foods. A general trophic grouping is bacterial feeders, fungal feeders, plant feeders, and predators and omnivores. For the purposes of our overview, one can use anterior (stomal or mouth) structures to differentiate feeding, or trophic, groups (Fig. 7.5) (Yeates and Coleman, 1982 Yeates et al., 1993). Plant-feeding nematodes have a hollow stylet that pierces cell walls of higher plants. Some species are facultative, feeding occasionally on plant roots or root...
Nematode Extraction Techniques
Nematodes may be extracted by a variety of techniques, either active or passive in nature. The principal advantage of the oldest, active method, namely the Baermann funnel method, is that it is simple, requiring no sophisticated equipment or electricity. It is based on the animal's movement and gravity. Samples are placed on coarse tissue paper, on a coarse mesh screen, and then placed in the cone of a funnel and immersed in water. After crawling through the moist soil and filter paper, the...
What Do Komodo Dragons Eat?
This article aims to answer the question what do komodo dragons eat. We will also discuss important informations regarding the Komodo dragon diet. Heavy, strong and deadly, the Komodo dragon has been a subject for fascination among scientists. They're so notorious they remind us of a mythical creature the dragon. And that's probably the reason why we call them dragons. These large lizards dominate their ecosystems with their ferocity and appetite.
What do Pheasants Eat: Read This First Before Feeding Your Pheasant!
This article aims to give you background in raising pheasants as pets. We will focus on the diet aspect of pheasants by answering the question what do pheasants eat. We will also discuss basic information about pheasants such as What are pheasants What do pheasants eat in the wild How do I start raising pheasants from chicks What should I feed my pet pheasants What are pheasants Pheasants are game birds that are closely related to chicken, partridges, and quails.
The Diversity Of Autotrophic Nitrifiers
For a group of microbes with such functional importance at a variety of scales, the nitrifiers are a remarkably depauperate group from a taxonomic standpoint. Although slow growth rates hinder cultivation-based analyses of their diversity, as do culture techniques that fail to reproduce the diversity of microhabitats in soil (see Chap. 3), even molecular methods fail to find much nitrifier diversity. There is, nevertheless, even in the single phylogenetic group to which most ammonia-oxidizing...
What do Peacocks Eat in the Wild and as Pets?
Because of its fascinating appearance, peacocks have been widely domesticated as pets. People are amazed when a peacock (male bird) begins to walk around and display its magnificent tail feathers. Peacock belongs to the pheasant family. Just like their cousins, peacocks also have a diverse and interesting diet. Naturally, peacocks are considered as ground eaters and will eat smaller animals that they might find along the way.
What Do Humpback Whales Eat?
Humpback whales are found in every ocean on Earth. They are intelligent creatures, that live in groups called pods. The average humpback whale weighs around 35 tons, or 80,000 lbs, and can grow up to 50 feet in length, so the definitive answer to what do humpback whales eat is definitely a lot of food The scientific name for the humpback whale is Megaptera novaeangliae'. They are mammals known as cetaceans.
Intromittent Organs
The need for a secure connection, then, may account for some of the claspers, hooks, and spines in the male's genitalic assemblage but cannot explain the bewildering complexity (Fig. 6.11E) of many components. The similarity of some cockroach structures to those of other, better-studied insects, however, allows us in some cases to make inferences from genitalic design. In particular, brushes and slender, elongate spines, rods, and flagellae, especially those with modified tips, may be sexually...
Range Of Habitats
Cockroaches are found in a continuum of dark, humid, poorly ventilated, and often cramped spaces either continuously or when sheltering during their non-active period. Although certain species may be associated with a particular crevice type like the voids beneath rocks or the space beneath loose bark, others are commonly found in more than one of these habitat subdivisions. Many species exploit the interconnectivity of dark, enclosed spaces wherever there is suitable food and moisture, and a...
In Existing Burrows and Nests
Some cockroaches specialize in using the niche construction, food stores, and debris of other species. Whether these cockroaches elude their hosts or are tolerated by them is unknown. Of particular interest are the cockroaches that live with insectivorous vertebrates such as rodents and some birds. How do the cockroaches avoid becoming prey A number of cockroaches live in the nests of social insects, although these relationships are rather obscure. Some cockroach species collected in ant and...
Listing of the Principal Artificial Structures Built by Beavers
Excavated tunnels and chambers in stream banks Piles of wood (tree branches and small trunks) Dome-shaped constructed wood piles with a central chamber Constructed channel obstructions made up of wood and sediments Habitation and protection from predators Source of food, especially in winter Habitation and protection from predators Creation of a pond that facilitates movements and protection from predators neering) for reintroducing beavers into watersheds where they had been trapped-out to...
Ecology of flea populations
Charles Krebs defined ecology as 'the scientific study of the interactions that determine the distribution and abundance of organisms' Krebs, 1994 3 . In other words, the main unit of ecological interest is not the individual organism but rather an assemblage of individuals belonging to the same species and coexisting in time and space. Contrary to that of most free-living species, spatial distribution of parasites is not continuous but consists of a set of more or less uniform inhabited...
Geographical distribution of fleas
Geographical range is an immanent feature of every recent or extinct species. Two main characteristics of a geographical range of a species are its position and its size. Many important ecological and evolutionary questions involve these two parameters. What determines the limits of species occurrences What are the causes of variation in the size of geographical range among and within taxa How are position and size of geographical ranges related Is the size of geographical range heritable, i.e....
Origin and evolution of fleas
One of the main impediments in studies of the evolution and phylogeny of Siphonaptera is morphological specialization related to their ectoparasitic way of life Whiting, 2002a . In particular, this specialization is reflected in the peculiar morphology of the head, thorax and genitalia. On the one hand, specialized characters are not especially informative for use in phylogenetic reconstructions. On the other hand, the sharing of these specialized characters by practically all flea species...
Size classSize class
Figure 15.9 The level of flea aggregation estimated as variance-to-mean ratio and prevalence of fleas in relation to host size in the bank vole Myodes glareolus, fieldmouse Apodemus agrarius and common vole Microtia arvalis. Redrawn from Krasnov et dl. 2006a reprinted with permission from the American Society of Parasitologists . 40 50 days Bashenina, 1981 . Another factor possibly contributing to the relatively low abundance and low levels or lack of aggregation of fleas in young age classes...
Skrjabingylosis
Museum curators and researchers dealing with collections of weasel skulls noticed long ago that many specimens were damaged in the postorbital region, immediately behind the eyes. The skulls had what appeared to be dark patches or swellings with thinned walls, and sometimes these had holes in them, even large openings (Figure 11.7). The cause of the damage became clear when the fresh heads were skinned and the swellings opened. Inside, a mass of bright red round worms could be seen crammed into...
Coastal Plain
Physiography The Coastal Plain, a 320,000-square-mile zone that extends east from the western limits of the southern forest in Texas to the Atlantic shore, supports the most extensive and productive pine forests of the South. A happy combination of the four factors of site makes this so. Geologically young, the underlying sediments of the region are mainly sands, gravels, clays, and marls, in strata that drop toward the coast. Older sediments are exposed in the interior, younger ones seaward....
Molecular Fossils Demonstrate Precambrian Origin of Dinoflagellates
The natural product chemistry of modern organisms shows that dinosterols are concentrated in, and are nearly exclusive to, dinoflagellates. Saturated dinosteroid (dinosteranes) and triaromatic dinosteroid hydrocarbons found in rock extracts and petroleum are molecular fossils of dinosterols. We observed a virtually continuous dinosterane record in Precambrian to Cenozoic organic-rich marine rocks. Ratios of dinosterane concentrations to those of steranes with affinities to other taxa are...
Copenhagen Becomes First Scandinavian City with a Mandatory Green Roof Policy
Last year's COP-15 event may have achieved epic fail status, but that's certainly not going to stop the former host city Copenhagen, Denmark from pushing their green standards a bit further. Copenhagen is now the first Scandinavian city to put a mandatory green roof policy into action. The new policy requires vegetation and soil to be a mandatory part in architectural planning in particular, it covers all roofs with a slope less than 30 degrees, plus the refurbishment of older roofs.
Phylogeny and evolution
All otters belong to the largest family of the Carnivora, the Mustelidae (martens). It is divided into subfamilies, the otters being the Lutrinae. Others are the Mustelinae (weasels, martens and minks), Melinae (badgers), Mellivorinae (honey- badger), Taxidiinae (American badger) and Memphitinae (skunks). Of all these, the Mustelinae are the closest relatives of the otters, and are their ancestral branch (Koepfli and Wayne 1998). The elongated body shape of the Mustelinae provided an excellent...
Order Actiniaria Sea Anemones
Throughout the world, sea anemones occur in most marine environments, from rocky and soft intertidal to deep abyssal substrata, and in many sizes from more than a metre in diameter down to a millimetre or two. Large sea anemones can be seen in both tropical reefs and deep Antarctic waters, but the families represented differ, with many of the deep sea species having strong gelatinous column walls or heavy external coatings and very large mouths while tropical species tend to have soft bodies,...
What Do Dragonflies Eat?
In this article, we will discuss the type of food that dragonflies in its natural habitat. What are dragonflies There are over 5,000 species of dragonflies. Dragonflies are insects that belong to the order Odonata, which means toothed one . This is because dragonflies have sharp serrated teeth. They are further categorized into the group, or clade, known as Anisoptera. This comes from the Greek words anisos pteron , which translates as uneven wing .
And the Distribution of Organisms
Although there are 270000 species of land plants (Hammond 1995), a series of filters eliminates most of these species from any given site and restricts the actual vegetation to a relatively small number of species (Fig. 1). Many species are absent from a given plant community for historical reasons. They may have evolved in a different region and never dispersed to the site under consideration. For example, the tropical alpine of South America has few species in common with the tropical alpine...