| Natural selection | Genetics | The modern synthesis | Speciation and phylogeny |
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1. There is a struggle for existence: more individuals are born than can survive
2. There is variation in populations 3. This variation is transmitted through natural selection
What are Darwin's 3 postulates of natural selection?
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Genotype refers to the specific combination of alleles in any given chromosome. Alleles are variations of a single gene. Therefore, alleles from the mother and the father combine to create the genotype for the offspring.
What is the difference between a genotype and an allele?
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By taking the number of individuals with a certain genotype and dividing that by the total number of individuals in the population.
How would you find the genotype frequencies in any given population?
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The biological species concept and the ecological species concept
What are the two main concepts that describe how we define species?
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a. phenotype
Natural selection acts on the
a. phenotype b. genotype |
Homozygous
_______ refers to an individual who has two copies of the same allele
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True
True or false: natural selection can change gene frequencies in a population.
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Allopatric speciation
Which type of speciation requires a physical barrier that initially isolates part of a population, interrupts gene flow, and allows the isolated subpopulation to diverge from the original population under the influence of natural selection?
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The drought caused seeds to be harder and larger, which meant smaller beaked individuals could not eat to survive and only larger beaked finches survived to pass on their genes.
How did the drought on Daphne Major affect the beak depth of finches on the island?
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3:1
When crossed, two heterozygous individuals will produce what phenotypic ratio?
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Adaptive radiation
What is it called when a single kind of animal or plant diversifies to fill many available niches?
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Little by little, with each small step being more advantageous than the last
How do complex adaptations evolve?
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A mutation
What is formed when a chromosome copies itself, but mistakes are made?
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A "family tree" that arranges groups of species that share a common ancestor based on shared characteristics.
What is a phylogeny?
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