Term
| What is the definition of evolution? |
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Definition
| -Descent with modification-Idea that over time the genetic make-up of a population changes |
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Term
| Distinguish small-scale evolution from large-scale evolution |
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Definition
| -Small scale: frequency of alleles in a population changes over time -- results in changes in variation and diversity within a population -Large scale: change occurs to a gene or genes in a population -- results in development of a new species, extinction of specie |
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Term
| In terms of evolution, why is it incorrect to state that humans descended from monkeys? |
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Definition
| -organisms descend from a common ancestor, they may share a common lineage but at some point they begin to develop their own unique genetic history |
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Term
| What are the three sources of genetic variation and describe how each creates variation within a population. |
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Definition
| a. Mutation: changes in DNA; may result in variants b. Gene flow: movement of gene in and out of a population; causes changes in allele frequency within a population, may bring in a new allele or gene c. Sexual Reproduction: creates new gene combinations; meiosis reshuffles genes on individual chromosomes, fertilization results in new combinations within populations |
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Term
| What is genetic drift? What are their effects on variation within a population? |
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Definition
| -Changes in allele frequency as a result of chance events. Sometime the traits of “lucky” individuals are passed from one generation to the next not as a result of being more fit for the environment but a result of chance events. |
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Term
| What is natural selection? What are their effects on variation within a population? |
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Definition
| -An orderly mechanism of evolution, environmental factors exist that result in certain traits of a population being more favored than others; result – individuals with the favored trait have a better chance of surviving and thus a better chance to reproduce than those with a less favorable trait. |
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Term
| Explain the principle of superposition |
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Definition
| -Geologic principle, in a sequence of undeformed sedimentary rocks, younger layers are found above older layers |
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Term
| Explain cross-cutting relationships |
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Definition
| -Rocks cross-cutting are younger than all the rocks that it cuts across and older than the rocks above it that it does not cut. |
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Term
1.Examine the diagram to the left and identify the layers
from youngest to oldest
[image] |
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Definition
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Term
1.Compare relative age to absolute age. |
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Definition
-relative age: actual age not determined, age is relative to surrounding layers: younger than the layers below
Them but older than the layers above them.
-Absolute age: more precise, quantifiable, based on radiometric dating (radioactive decay). |
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Term
| Explain the process of radioactive decay and how it can be used to measure the age of rocks. |
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Definition
-Some elements are very unstable and decay (lose protons and/or neutrons) to a more stable state, decay is very
constant. Measured in half-life: the number of years it takes or one-half the unstable atoms to become stable
-The decay can be measured by looking at the ratio of parent (unstable) atoms to daughter (stable) atoms.
-Use a decay chart for the parent material, find the ratio of parent to daughter on the chart to determine the age. |
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Term
| [image]The diagram below represents the present number of decayed and undecayed atoms in a sample that was originally 100% radioactive material. If the half-life of the radioactive material is 1,000 years, what is the age of the sample represented by the diagram? |
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Definition
-Begin with 32 parent atom
-after 1000 yrs
16 parent/16 daughter
-after another 1000 yrs
8 parent/24 daughter
-after another 1000 yrs
4 parent/28 daughter
Since there are 8 undecayed atoms left, that matches 2 half-lifes or 2000 years old
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Term
| Define the term: gene pool. |
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Definition
-The combined genetic information of all members of a population |
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Term
1.In what way(s) are single gene and polygenic traits similar? Way(s) they are different. |
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Definition
Similar: act on genes, effect allele frequency in the population |
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Term
1.How does Natural Selection effect a single gene trait? |
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Definition
-Natural selection effects phenotypes
-Because single gene traits have fewer alleles, causes more dramatic changes in frequencies
-less favored traits more easily removed
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Term
1.Identify the three types of selection on polygenic traits and explain the effects of each type on variation within a
population. |
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Definition
-Directional selection: one end of the curve is favored and the frequency shifts toward that favored end
-Stabilizing selection: the middle of the curve is favored and the frequency squeezes toward the middle
-Disruptive selection: both ends of the curve are favored and the curve pushes out from the middle increasing
The frequency at both ends of the curve (camel’s humps)
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Term
| What is the Hardy Weinberg Equilibrium? |
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Definition
-A mathematical model of a non-evolving population
-Predict allele frequency
-predict genotype frequency
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Term
| What must be assumption must exist about the condition of the population for Hardy Weinberg to be acting? |
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Definition
-The population is large (there is no genetic drift)
-There is no gene flow between populations, from migration or transfer of gametes
-Mutations are negligible
-Individuals are mating randomly
-Natural selection is not operating on the population |
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Term
1.Identify which each of the Hardy Weinberg symbols below represent. |
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Definition
p = allele frequency of the dominant trait
q = allele frequency of the recessive trait
p2 = frequency of homozygous dominant genotype (ex. BB)
q2 = frequency of homozygous recessive genotype (ex. bb)
2pq = frequency of heterozygous dominant genotype (ex. Bb) |
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