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Evolution- change in POPULATION over time (Evidence for Evolution (Pattern…
Evolution- change in POPULATION over time
Evidence for Evolution
Patterns in Fossil Records
Relative Dating and Radioactive Dating
Pattern of Embryological Similarities
Homologous structures observed during early embryological development
Pattern of Anatomical Similarities
Homologous structures--similar structures in related organisms that are a result of common ancestry
Vestigial Structures-- little or no purpose to present organism, but provides evidence for common ancestry
Amino Acid Sequences and DNA Sequences
molecular evidence
gene expression--which genes are turned on and off
Geographic-- PANGEA
Mechanisms
Gene Flow--movement of individuals from one population to the other
Ex. Pollen being blown to a new destination
Genetic Drift-- some individuals that leave descendants by chance
Does NOT work to produce adaptations
by chance
Mutation--change in DNA
the ultimate source of genetic variation
random
Natural Selection-- occurs because there is variation, heredity, and the environment can't sustain unlimited population growth
Microevolution
a change in gene frequency within a population
happens from generation to generation
Macroevolution
evolution above the species level
happens over long periods of time
Homologous
characters in different organisms that are similar because they were inherited from a common ancestor that also had that character
Ex. Forelimbs of tetrapods
Analogous
have separate evolutionary origins, but are superficially similar because they have both experienced natural selection that shaped them in a similar way
Convergent evolution-- process in which two distinct lineages evolve a similar characteristic independently of one another
Ex. flight in bats v.s. flight in birds
Adaptation
a feature that is common in a population because it provides some improved function
well fitted to their function and are produced by natural selection
Ex. mimicry
Adaptive Radiation
a single species evolves into a number of other species
they are distinct from one another but are closely related
each species is specialized for a different environment
Sexual Selection
acts on an organisms ability to successfully copulate with a mate
makes many organisms go to extreme lengths
powerful enough to produce features that are harmful to the individual's survival
Artificial Selection
people(instead of nature) select which organisms get to reproduce
farmers and breeders allow only the plants and animals with desirable characteristics to reproduce
Co-evolution
cases where two or more species reciprocally affect each other's evolution
likely to happen when different species have close ecological interactions with one another
Ex. predator/prey and parasite/host
Speciation
Species--a population of similar organisms that can interbreed to produce viable, fertile offspring
lineage-splitting event that produces two or more separate species
geographic isolation is an important step of some speciation events