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The care of offspring among amphibians has been little studied but, in general, the larger the number of eggs in a batch, the less likely it is that any degree of parental care takes place. Nevertheless, it is estimated that in up to 20% of amphibian species, one or both adults play some role in the care of the young. [128]
Toxic agent, serine protease BLTX, in the venom produced by two distinct species, the North American short-tailed shrew (Blarina brevicauda) and the Mexican beaded lizard, undergo convergent evolution. Although their structures are similar, it turns out that they increased the enzyme activity and toxicity through different way of structure changes.
This form of competition typically manifests in new equilibrium abundances of each prey species. For example, suppose there are two species (species A and species B), which are preyed upon by food-limited predator species C. Scientists observe an increase in the abundance of species A and a decline in the abundance of species B.
The ontogenetic niche shift varies across species; in some it is hardly visible and gradual (for example a change in diet or in size in mammals and reptiles), while in others it is obvious and abrupt (the metamorphosis of insects, which often results in changing habitat, diet and other ecological conditions).
It occurs when two or more species in a habitat affect shared natural enemies in a higher trophic level. [5] If two species share a common predator , for example, apparent competition can exist between the two prey items in which the presence of each prey species increases the abundance of the shared enemy, and thereby suppresses one or both ...
The distribution of 2,873 globally threatened amphibian species. [2] In the past three decades, declines in populations of amphibians (the class of organisms that includes frogs, toads, salamanders, newts, and caecilians) have occurred worldwide. In 2004, the results were published of the first worldwide assessment of amphibian populations, the ...
Consumer–resource interactions are the core motif of ecological food chains or food webs, [1] and are an umbrella term for a variety of more specialized types of biological species interactions including prey-predator (see predation), host-parasite (see parasitism), plant-herbivore and victim-exploiter systems.
Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia . They inhabit a wide variety of habitats , with most species living within terrestrial , fossorial , arboreal or freshwater aquatic ecosystems .