chapter 2/3 Flashcards
define populations
a connection of organisms of the same species
define adaptations
an inherited trait or set of traits that improve the chance of survival
the theory of evolution is…
why organisms with similar biology are so different in form and function.
what is the selection process
favoriting individuals over others for a particular environment
what is direct evidence?
evidence from the past
what are examples of direct evidence?
fossils
divergent evolution
what is the problem with fossils?
incompleteness of all the species , only a portion of an organism, and only fossilized rivers and oceans
what is divergent evolution?
organisms that become less alike over time
what is indirect evidence?
evidence observed today
what are examples of indirect evidence?
embryology
homologous structures
analogous structures
biochemical evidence
what are homologous structures?
structures with similar Origin but different uses
what are analogous structures?
unrelated structures having similar functions
what was the early view on organisms?
organisms were thought to be “fixed” or unchanging
what did Aristotle propose?
creatures be arranged in a hierarchy based on complexity.
Pierre-Louis de maupertuis considerd offspring to be…
a accidental recombination of “elementary particles”
George-Louis leclare de Buffon proposed
- creation did not over in a single location
2. species were subjected to modification overtime
Jean-baptiste de Lamark
proposed…
- law of use and disuse:organisms had ability to develop new body parts
- law of acquired inheritance:new features= passed to offspring
the names of two men that proposed the theory of natural selection
Charles Darwin and Alfred Wallace
natural selection is…
- overproduction
- struggle for existance
- variation
- survival of the fittest
- origin of new species by inheritance of successful variations
what are some examples of evolution observed today?
- sexual reproduction
- artificial selection
- accidental selection
- mutations
define directional selection
a steady trend in some traits overtime
define stabilizing selection
organisms with extreme variations from the “norm” do not survive
define disruptive selection
extreme variations= survival advantage,trait passed on,population may diverge into separate groups
speciation is…
- a population is split into two
- each population starts to adapt to its environment by natural selection
- the two populations remain reproductively isolated for a long time
- mutations and genetic recombination =loss interbreeding
define reproductive isolation
prevention of breeding when a species split
what are some pre-mating factors?
- geography issues
- habitat preference
- behavioral differences
- mating seasons
what are some post-mating factors?
- death of embryo or fetus
- sterility of offspring
define evolution
the change of over a series of generations
