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16 Cards in this Set
- Front
- Back
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What is the theory of gradualism? Who came up with it ? |
Geologic change results from slow and gradual, continuous processes ; Created by James Hutton |
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Describe Lamarck's Theory of Evolutionary. |
Theory based on the idea of inheritance of acquired traits through "use & disuse". |
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How does Lamarck's theory differ from Darwin's theory? |
Lamarck agreed environments shaped organisms, but he believed that traits were passed on through use and disuse, while Darwin believed in natural selection and "descent with modification". |
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What are the key ideas of natural selection ? |
•Competition for limited resources results in different survival •Evolutionary Fitness: Individuals with more favorable phenotypes are more likely to survive and produce more offspring, and pass traits to future generations •If environment changes or individuals move to new environment, new adaptations and new species may arise •Populations evolve, not individuals |
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Compare Natural Selection to Artificial Selection. |
Natural Selection: •Nature decides •Works on individual (Example: Beaks) Artificial Selection: •"Man" decides •Selective breeding •Inbreeding occurs (Example: Dogs) |
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Describe the following evidences of evolution: |
•Homology •Fossils •Direct Observations •Biogeography |
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Homology |
Characteristics in related species can have underlying similarities even though functions may differ.
•Examples: -Homologous Structures: similar anatomy from common ancestors -Embryonic Homologies: similar early development -Vestigial Organs: structures with little or no use -Molecular Homologies: similar DNA and amino acid sequences
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Fossils |
Remains or traces of organisms from past •Found in sedimentary rock •Shows evolutionary changes that occur over time and origin of major new groups of organisms |
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Direct Observations |
Examples: •Insect populations become resistant to pesticides • Antibiotic resistant bacteria •Peppered moth (pollution in city vs country) |
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Biogeography |
Geographic distribution of a species •Species in nearby geographic areas resemble each other •Continental drift and Pangea explains similarities on different continents •Endemic Species: found at a certain geographic location and nowhere else (Ex: Marine Iguanas in the Galapagos) |
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What was one important piece of evidence that Darwin was missing when he first came up with his theory of evolution based on natural selection? |
He did know how organisms passed traits on to their offspring. Mendelian genetics supports Darwin's theory>>> evolution is based on genetic variation |
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What is the Hardy-Weinberg Equilibrium? |
The allele and genotype frequencies of a population will remain constant from generation to generation UNLESS they are acted upon by forces other than Mendelian segregation and recombination of alleles. |
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5 conditions for evolution not to occur |
1. No mutations 2.Random mating 3. No natural selection 4. Extremely large population size 5. No gene flow |
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What are three processes that cause genetic variation in gene pools? |
Point Mutations: changes in one base (example: sickle cell)
Chromosomal Mutations: delete, duplicate, disrupt, rearrange >> usually harmful
Sexual Recombination: contributes to most genetic variation in a population 1. Crossing over (meiosis-prophase I) 2. Independent Assortment of Chromosomes (during meiosis) 3. Random Fertilization (sperm & egg)
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Name and describe the two types of genetic drift. |
Founder Effect: A few individuals isolated from larger population •Certain alleles under/over represented Bottleneck Effect: Sudden change in population drastically reduces population size |
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Name and describe the three modes of frequent distribution |
1. Directional Selection: Favoring one of the extremes 2. Disruptive Selection: Both extremes are favored. The ones in the middle are not preferable. 3. Stabilizing Selection: Intermediate is favored |
