Evolution Flashcards
Evolution
The process by which new types of organisms develop from existing organisms.
Fossils
Remains of organisms that lived millions of years ago
Homologies
Features or characteristics shares by a group of species because they were inherited from a common ancestor.
Analagous
Body structures that have the same function but have a different origin and a slightly different structure
Convergent evolution
When organisms not closely related evolve similar adaptations independently.
Modification by descent
When related species share characteristics because they inherited them from a common ancestor.
Divergent evolution
Species evolve from a common ancestor and share similar characteristics
Vestigial structures
Small, poorly developed structures that have no real use but have been inherited from an ancestor, e.g. whales and sharks have pelvises and undeveloped hind leg bones
Macroevolution
Refers to major evolutionary changes over time, the origin of new types of organisms from previously existing but different ancestral types
Microevolution
Changes happens within a group but the descendant is clearly of the same type as the ancestor.
Genetic drift
Random fluctuations in the numbers of gene variant in a population.
Punctuated equilibrium
Evolution does not occur gradually, but in sudden bursts
Gradualism
Process of gradual change in phenotypic characteristics.
Population
A group of organisms of the same species that live in a particular place at a particular time with the ability to freely interbreed
Gene pool
The total number of alleles of all reproductive individuals in a particular population.
Gene flow
The exchange of alleles between populations
Founder effect
A loss of genetic variation when a new population is formed from a small number of individuals moving to a new area
Lamarck
Environment is important in causing changes in organisms.
Evolution occurs when an organism uses a body part in such a way that it is altered
during its lifetime – then inherited by offspring.
Creatures could develop new organs or change structure and function of existing
ones if used/disused.
Darwin
Organisms produce a large number of organisms, more than is needed for survival of the population
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