Animal Diversity Index
Nature’s complexity distilled into a single number, the Animal Diversity Index reveals ecosystem health, but what secrets does it hide
Ecology
Explore the delicate balance of ecosystems, biodiversity conservation, and the interplay between organisms and their environment. Join us as we delve into pressing environmental issues and innovative solutions shaping the future of our planet
Animal Behavior Theories
Shedding light on why animals act as they do, animal behavior theories offer diverse perspectives that will leave you
Wildlife Conservation Techniques
Wildlife conservation techniques offer hope for endangered species, but which methods truly make a difference? Discover the surprising answers.
Characteristics of Threatened Species
Although a large number of factors can make a species vulnerable to extinction, conservation biologists have observed that the species most vulnerable to extinction belong to one of six main groups: • Species with small populations: some species have very small populations, consisting of a few individuals. These small populations are highly vulnerable to random …
What does genetic drift cause?
Define genetic drift in biology In wild populations, there are always relatively common and relatively rare alleles. Small populations are at risk of losing genetic variation much faster than large populations. While common alleles generally tend to remain common, rare alleles are likely to be randomly lost in subsequent generations. Consider how each parent only …
Demographic and environmental stochasticity
Demographic stochasticity Population stochasticity (also known as demographic change) refers to random variations in the demographic characteristics of a population (eg. sex ratios, birth rate, death rate), the cumulative effect of varying the fitness of individual organisms. In any natural population founded by only a few individuals by definition start off with low genetic diversity, …
What is population bottleneck?
In some taxa, such as butterflies, annuals, and amphibians, population size varies dramatically from generation to generation. In recent years, populations may be so large that they seem in little danger of extinction. However, years of abundance can be misleading when followed by subsequent years of low abundance. Typically, in a population of individuals experiencing …
What causes outbreeding depression?
Large populations have many ecological, behavioral, and physiological mechanisms that prevent hybridization, the production of offspring among genetically distant taxa, whether they be individuals of different species, or individuals of the same species but with different adaptations (the latter being intraspecific hybridization). As with inbreeding depression, these mechanisms may fail in small populations, leading to …
Heterosis and inbreeding depression
Mating among closely related individuals, which occurs in small populations, often results in lower reproductivesuccess and weaker offspring. In large populations, a variety of instinctive mechanisms are in place to promote heterosis, which occurs whenoffspring have a level of genetic variation that improves their individual evolutionary fitness. Some species are predisposed to disperse from their …
What is thermal pollution and what causes it?
Thermal pollution describes localized human-induced temperature changes in the natural world. Aquatic ecosystems represent one of the ecosystems most vulnerable to thermal pollution. For example, when water is released from big dams, it comes from the colder middle and lower strata of the reservoir, leading to rapid cooling of aquatic ecosystems further downstream. The opposite …