Microevolution Flashcards
what is evolution
change over time; process by which organisms have descended from ancient organisms
who is lanmark
proposed use and disuse theory (organs that are used are kept, organs that are unused are lost over time)
who is hutton
studied rock layers that formed over millions of years (gradualism)
who is lyell
studied how processes that occurred millions of years ago still occur today
who is darwin
developed the theory of natural selection
who is malthus
not all offspring survive
what were darwin’s observations
- different animals are adapted to living in different areas
- fossils showed animals that are now nonexistent
- members of the same species can vary greatly
what is natural variation
differences between individuals of the same species
what is natural selection
survival of the fittest
three parts of natural selection
- all organisms struggle for existence
- fitness is the result of adaptations
- the most fit animals survive
what is artificial selection
humans select the variations provided by nature
what is descent with modification
species have descended with changes over time
what is common descent
all living things arise from a common ancestor
evidence for evolution (4 parts)
- fossils - found in sedimentary rock; show ancestor
- biogeography - the study of where organisms live now and where their ancestors lived in the past
- homologous structures - body structures that are similar among organisms of different species but that are adapted to different purposes as the result of descent with modification
- analogous structures - body parts that serve similar functions but do not share structure and development (no common ancestor)
analogous structure checkbox
- dissimilar in anatomy
- similar functions
- develop in unrelated animals
- not inherited from a common ancestor
- development pattern not similar
- dissimilar structure and orgin
homologous structure checkbox
- similar in anatomy
- dissimilar functions
- develop in related animals
- inherited from a common ancestor
- developmental patterns is similar
- similar in structure and orgin
what are vestigial organs
structures that don’t serve important functions. they are inherited from ancestors but have lost much of their original size and function
what is embryology
similarities in early development stages
what is DNA similarities/sequencing
overwhelming similarities in genetic code of all organisms, along with homologous genes and molecules, provide evidence of common descent
what is directional selection
phenotypes at one end have a higher fitness (whole curve shifts in one direction)
what is stabilizing selection
individuals in the center have higher fitness (curve narrows)
what is disruptive selective
individuals at both ends have higher fitness (curve splits in two)
what is a gene pool
consists of all genes present in a population, including all alleles for each gene
what is allele frequency
the number of times that an allele occurs in a gene pool compared to the number of alleles in that pool for the same gene
