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The challenge for abiogenesis (origin of life) [7] [8] [9] researchers is to explain how such a complex and tightly interlinked system could develop by evolutionary steps, as at first sight all its parts are necessary to enable it to function. For example, a cell, whether the LUCA or in a modern organism, copies its DNA with the DNA polymerase ...
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
Unsolved problems relating to the behaviour of animals include: Homing. A satisfactory explanation for the neurobiological mechanisms that allow homing in animals has yet to be found. Flocking (behavior). How flocks of birds and bats coordinate their movements so quickly is not fully understood.
The timeline of the evolutionary history of life represents the current scientific theory outlining the major events during the development of life on planet Earth.Dates in this article are consensus estimates based on scientific evidence, mainly fossils.
Behavioral ecology, also spelled behavioural ecology, is the study of the evolutionary basis for animal behavior due to ecological pressures. Behavioral ecology emerged from ethology after Niko Tinbergen outlined four questions to address when studying animal behaviors: What are the proximate causes, ontogeny, survival value, and phylogeny of a behavior?
The evolution of the digestive system has formed a significant influence in mammal evolution. With the emergence of mammals, the digestive system was modified in a variety of ways depending on the animal's diet. For example, cats and most carnivores have simple large intestines, while the horse as a herbivore has a voluminous large intestine. [127]
For example, several studies have shown that performance is better on, for example, a color discrimination (e.g. blue vs green) after the animal has learned another color discrimination (e.g. red vs orange) than it is after training on a different dimension such as an X shape versus an O shape.
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).