Chapter 6 Flashcards

1. In the context of evolution, a trait that increases the probability that an individual will leave offspring in subsequent generations. 2. In the context of sensory processing, the progressive loss of receptor sensitivity as stimulation is maintained. See Figure 8.7.
One of two or more different forms of a gene or genetic locus.
Similarity of function, although the structures of interest may look different. The human hand and an elephant’s trunk are analogous features. Compare homology.
Of or related to Australopithecus, a primate genus, known only from the fossil record, thought to be an ancestor to humans. See Figure 6.18.
A complex of condensed strands of DNA and associated protein molecules; found in the nucleus of cells.
convergent evolution
The evolutionary process by which responses to similar ecological features bring about similarities in behavior or structure among animals that are only distantly related (i.e., that differ in genetic heritage).
cortex (pl. cortices)
The outer covering of the cerebral hemispheres, also called neocortex, that consists largely of nerve cell bodies and their branches. See also cerebral cortex.
ecological niche
The unique assortment of environmental opportunities and challenges to which each organism is adapted.
encephalization factor
A measure of brain size relative to body size.
A cast of the cranial cavity of a skull, especially useful for studying fossils of extinct species.
The process by which a population of interbreeding individuals changes over time.
evolution by natural selection
The Darwinian theory that evolution proceeds by differential success in reproduction.
A length of DNA that encodes the information for constructing a particular protein.
The study of inheritance, including the genes encoded in DNA.
genus (pl. genera)
A group of species that resemble each other because of shared inheritance. See Figure 6.3.
A physical resemblance that is based on common ancestry, such as the similarity in forelimb structures of different mammals. See Figure 6.1. Compare homoplasy and analogy.
A physical resemblance that is due to convergent evolution, such as the similar body form of tuna and dolphins. Compare homology.
A change in the nucleotide sequence of a gene as a result of unfaithful replication.
A student of the form and classification of organisms.
See cortex.
The evolutionary history of a particular group of organisms. See Figure 6.4.
sexual selection
Darwin’s theoretical mechanism for the evolution of anatomical and behavioral differences between males and females.
A group of individuals that can readily interbreed to produce fertile offspring. Individuals of different species produce either no offspring or infertile offspring. See Figure 6.3.
The classification of organisms. See Figure 6.3.