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20 Cards in this Set
- Front
- Back
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Briefly describe Lamarck's Theory:
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Altered environment changes of phenotype
This happens DURING LIFE (after organism is born) Change is passed on to its offspring |
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Briefly describe Darwin's Theory:
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Phenotype randomly changes during sexual reproduction
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How does variation happen?
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Mutation and recombination of alleles changes genes/phenotype
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What is Natural Selection?
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Responsible for development of new species from existing ones
New environment + mutation → adaptation |
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What is Directional selection?
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Natural selection favours organisms with one extreme form of a characteristic
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What is Speciation?
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Splitting of one into more species.
Emigration/immigration moves alleles between populations |
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What are the three types of Speciation?
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Reproductive Isolation, Allopatric Speciation (geographical isolation) and Sympatric Speciation (reproductive isolation).
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What is Habitat isolation?
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populations inhibit different local habitants within one environment
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What is Temporal isolation?
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Living in the same environment but are reproductively active at different times
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Describe Behavioural isolation:
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two populations have different courtship patterns
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What is Geographical separation?
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Populations inhabit different islands, continents etc
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Explain speciation in terms of Gametes mortality:
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The sperm cannot reach or fertilize the egg.
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How does Zygote mortality affect speciation?
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Fertilisation occurs, but zygote fails to develop
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Explain the Allopatric Speciation (geographical isolation):
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Physical barrier (water, mountains, dessert) divides a population.
Two different environments evolve. Natural selection occurs. Genetic drift changes genotype and phenotype. Two populations evolve separately. Reproductively isolated so 2 distinct species |
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Name the 4 types of Fossil dating:
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Radioactive isotopes, Stratigraphy, Potassium-argon dating and Carbon dating.
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Briefly exaplain the process of Radioactive isotopes dating:
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Slowly decay over time
Measured by using its half-life |
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Describe the limitations to radioactive isotopes dating?
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There are none, it isnt affected by temp, pressure etc.
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What is Stratigraphy?
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Fossil contained within a rock can be dated by assessing its number of layers
The older the rock, the more layers present, the older and deeper the fossil |
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What are the limitiation of Statigraphy?
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Earthquakes or volcanic eruptions may displace fossils within rocks
Fossil may be washed out and found at a different place |
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Describe the process of Carbon dating:
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Radioactive carbon (14C) is found in CO2
CO2 is used and stored by plants Animals eat plants and store 14C in their body |
