Evolution

• Fossil Record – the physical proof of fossils (eggs, body parts, foot prints, etc) helps us to understand the sequence of events over time in respect to which organisms were alive, where they lived, what they looked like and so forth
• Biogeography: study of distribution of plants, animals, and other forms of life across continents and islands.
• Homologous Structures– organisms that are descended from a common ancestor share common ancestral traits that may have developed to perform different functions
• Vestigial Structures – a structure that is a remnant of an organism’s

  evolutionary past and has no function; often homologous to structures

  that are useful in other species; indicate a common ancestor
• Analogous Structures – unrelated (or more distantly related)

  species of animals or plants develop similar advantageous traits

  when exposed to similar environments
• Convergent Evolution – two or more unrelated species become more and more alike (this is due to common environmental pressures, not due to ancestry); these resulting similarities are analogous (not homologous)
• Embryology – the branch of Biology that deals with the formation, early growth, and development of living organisms; the high degree of similarity of these early developmental forms strongly supports the idea that species have arisen from common ancestors
• Comparing DNA (or protein sequences) helps reveal evolutionary relationships

  • The more DNA nucleotides two species have in common, the more closely related the two species are
• Speciation: changes in isolated populations that lead to the formation of new species

  • When they can no longer reproduce with one another
• Adaptive radiation (aka divergent evolution)– two or more related species become less and less similar over time. (finches)
• Habitat isolation: Different environments

  Ex: Ladybugs feeding on diff plants
• Temporal isolation: Active or fertile at different times.

  Ex: Releasing pollen at different times of day
• Behavioral Isolation: Different courtship activities

  Ex: different songs to attract mate
• Mechanical Isolation: Mating organs are incompatible

  Ex: humans can’t mate with flowers
• Genetic isolation: Gametes cannot unite

  Ex: Sea urchin gametes are incompatible
• Hybrid inviability: Hybrid offspring fail to reach maturity
• Hybrid Infertility: Hybrid offspring unable to reproduce
• Hybrid Breakdown: Second gen hybrid offspring have reduced fitness

  Ex: Offspring of hybrid mosquitoes have abnormal genitalia
• Domain, Kingdom, Phylum, Class, Order, Family, Genus