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28 Cards in this Set
- Front
- Back
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Evolution |
A change in a species over time |
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Species |
A group of organisms that can produce fertile offspring with each other |
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Adaptation |
A trait that allows an organism to better survive its environment |
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"Fittest" organisms |
Organisms best adapted to their environment |
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Natural selection |
Darwin's explanation on how species are created. |
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Steps to natural selection |
1. Overpopulation - population is too large for its environment 2. Struggle for resources - organisms fight over limited resources 3. Survival of the fittest - Only the best adapted for survival will live to reproduce and pass on their traits |
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Artificial Selection |
Humans select a natural organism variation to be successful and reproduce. |
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Stabilizing selection |
The environment favors average individuals in a population |
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Directional selection |
favors one of the extreme variations of a trait |
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Disruptive selection |
Favors individuals with either extreme of a trait |
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Sexual selection |
Mate is chosen on their physical appearance or strength |
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Jean Baptiste Lamarck |
First person to propose theory of how new species came into being (aka evolution). Physical traits gained during organisms' lives get passed on to their offspring.
Ex. Ripped mouse = ripped baby mice |
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Disproving Lamarck |
Some guy tries to disprove Lamarck's theory. He sets up an experiment in which he cuts off the tails of mice. According to theory, the tails should get smaller as new generations reproduce. |
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Darwin's observations |
Goes to the Galapagos islands and notices the different types of finches and tortoise on each island. Birds on different islands had different beaks and tortoises had different shells and necks.
He also found fossils similar to living animals |
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Homologous Structures |
Body structures that share the same basic body plan due to a shared common ancestor |
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Vestigial Structures |
Body structures that are generally not used in an organism but are still present. |
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The Fossil Record |
The fossil record shows changes in species over time. Any one species line or family tree can be traced backwards or forwards in time by aging fossils |
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Comparative Embryology |
All animals with a backbone use the same genes to develop when embryos |
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Molecular Evidence |
Proteins from many various species all share the same protein structures |
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Hardy-Weinberg Principle and Requirements for Evolution |
Evolution will NOT happen if these are true: 1. Random Mating 2. Large Population 3. No movement into or out of a population 4. No mutations 5. No Natural Selection
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Genetic Drift |
In a small population a certain trait may randomly become dominant because of the few individuals in the population |
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Genetic Equilibrium |
The gene pool of a population does not change and is steady |
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Terms: Speciation Gene pool Gene flow Allelic Frequency |
Speciation - formation of a new species Gene pool - all of the traits in one population Gene flow - the movement of genes into or out of a population Allelic Frequency - How frequent a trait appears in a population |
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Reproductive Isolation |
How new species are made. Three types: 1. Behavioral (sexual) selection 2. Geographic 3. Temporal |
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Gradualism |
Evolution slowly occurs as an environment changes over time |
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Punctuated Equilibrium |
A major change in the environment forces evolution to happen rapidly |
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Convergent Evolution |
When two organisms develop similar traits to accomplish the same goal |
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Adaptive Radiation |
One species evolves into multiple different species to suit different environments |
