study guide on evolution Essay

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Review for Ch. 16-19 Test
Change over time (it is a theory)
Charles Darwin is known as father of evolution
Descent with modification
Living species have descended with changes from other species
Homologous structures
Same structures, different functions, different environments and common ancestor
Vestigial organs
Organs reduced in size that become traces of homologous organs in other species (e.g. appendix)

Common descent
All living things are related because they came from a common ancestor
Supported by the fossil record
Natural selection
Survival of the fittest
Individuals most likely to survive are those with characteristics that gives them an advantage in a given environment
Fitness is the ability to survive and reproduce
If you have 2 groups of birds, one with a smaller beak and the other with a larger one, and it is easier for the group with the smaller beak to eat, that group will be the one to survive and reproduce thus making the new generations have smaller beaks.
Inherited characteristic that improves an organisms fitness

Embryological similarities

Genetic Variation
Mutations and genetic shuffling are the main sources
The frequent use of pesticides, antibacterial soaps/lotions, and antibiotics will result in insects or bacteria developing resistance to these items this rendering their actions ineffective.
Genetic drift random change in allele frequencies seen when a small group colonizes a new habitat affects smaller populations
Isolating Mechanisms – prevent speciation (formation of new species)
Reproductive – two populations have separate gene pools and can’t breed/reproduce
Behavioral – populations can’t breed due to differences in courtship rituals
Geographical – populations separated by geographical barriers
Temporal – species reproduce at different times
Major biological changes evident in the fossil record
Adaptive radiation
Diverse species as a result of adaptation to different environments
Punctuated equilibrium
Species diverge in spurts of rapid change
Species evolve in response to changes in one another
Herbivorous insects developing resistance to toxins from plants
The plants developed the toxins as a defense mechanism for the insects that were eating them
Convergent evolution
Acquisition of the same biological traits in unrelated lineages
Dolphins (mammals), penguins (birds), and sharks (fish) all have appendages that enable them to swim

History of life
Earth’s early atmosphere contained water vapor, carbon dioxide, hydrogen sulfide, carbon monoxide, ammonia, and hydrogen
Organic molecules (e.g. amino acids and…