exam 2 Flashcards
define Gene Pool
the combination of all the genes (including alleles) present in a reproducing population or species. A large gene pool has extensive genomic diversity and is better able to withstand environmental challenges.
Define natural selection
the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin, and it is now regarded as be the main process that brings about evolution.
Define Evolution
descent with modification,” the idea that species change over time, give rise to new species, and share a common ancestor.
define Speciation
the formation of new and distinct species in the course of evolution.
Define Adaption
Adaptation is the act of changing something or changing your behavior to make it suitable for a new purpose or situation. Most living creatures are capable of adaptation when compelled to do so.
Define Gene Flow
Gene flow and natural selection are two central, and usually opposing, evolutionary forces: gene flow distributes, homogenizes, and maintains genetic variation that can act as the ‘stuff of evolution’, while natural selection reduces genetic variation to the variants that favor survival and reproduction.
Define Isolation
the process or fact of isolating or being isolated.
Define Homologous Structures
Homologous structures are similar physical features in organisms that share a common ancestor, but the features serve completely different functions. An example of homologous structures are the limbs of humans, cats, whales, and bats.
Define Analogous Structures
Analogous structures are features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature (compare to homologous structures) and which evolved in response to a similar environmental challenge.
Define Vestigial Structures
Vestigial structures are features of an organism that are considered to have lost much or all of their original function through evolution. These structures can provide insight into the environment and behaviors of a species’ ancestors and how they have evolved through time.
Define Convergent Evolution
Convergent evolution is the process whereby the same biological trait is developed in unrelated lineages – or, in other words, how very different organisms “navigate” to the same biological solution from very different starting points. The camera-eye of the vertebrate is a classical example
Define Transition Fossil
Fossils or organisms that show the transformation from an ancestral form to descendant species’ form. For example, there is a well-documented fossil record of transitional forms for the evolution of whales from their amphibious ancestor.
Define Artificial Selection
Artificial selection is the process by which humans choose individual organisms with certain phenotypic trait values for breeding. If there is additive genetic variance for the selected trait, it will respond to the selection, that is, the trait will evolve.
Identify molecules which can be used to support evidence of evolution
Evidence for evolution: Molecular biology
Like structural homologies, similarities between biological molecules can reflect shared evolutionary ancestry. At the most basic level, all living organisms share: The same genetic material (DNA) The same, or highly similar, genetic codes.
Compare Darwin’s Theory to Lamark’s
Explain Darwin’s Theory of Evolution through Natural Selection
Unlike Lamarck, who said that traits could develop and change during an animal’s lifetime, Darwin believed that individuals were simply born with different traits and that these differences were mostly random.
