Back to AI Flashcard MakerBiology /Bio 130 Exam 4 Part 2
what is nondisjunction
a failure of chromosomes to separate from one another during meiosis (I or II)
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Key Terms
Term
Definition
what is nondisjunction
a failure of chromosomes to separate from one another during meiosis (I or II)
what increases the rate of nondisjunction
the age of a woman
what does nondisjunction lead to
can lead to xxx, xxy, xo zygotes are rare but well-studied genetic disorders (yo is not viable)
what is a genetic chimera and how it is created
2 fertilized eggs fuse into one 2-celled embryo
what are the differences between a hypothesis, scientific theory, and a scientific law
hypothesis = a proposed explanation that may not get/have evidence to support it; scientific theory = well supported, based on reproducible experiment...
what is the process of evolution? On what level of life does it act?
evolution occurs at the population levels (individuals do not evolve); evolution is change in the genetic makeup (change in the population of alleles ...
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| Term | Definition |
|---|---|
what is nondisjunction | a failure of chromosomes to separate from one another during meiosis (I or II) |
what increases the rate of nondisjunction | the age of a woman |
what does nondisjunction lead to | can lead to xxx, xxy, xo zygotes are rare but well-studied genetic disorders (yo is not viable) |
what is a genetic chimera and how it is created | 2 fertilized eggs fuse into one 2-celled embryo |
what are the differences between a hypothesis, scientific theory, and a scientific law | hypothesis = a proposed explanation that may not get/have evidence to support it; scientific theory = well supported, based on reproducible experimentation and observations; scientific law = to a better-supported theory like theories; all things that are true for theories are true for laws |
what is the process of evolution? On what level of life does it act? | evolution occurs at the population levels (individuals do not evolve); evolution is change in the genetic makeup (change in the population of alleles -> certain alleles become more or less numerous) |
what is the process of natural selection | the idea that the individuals that survive and reproduce will be those that have traits or alleles that help them survive and reproduce, and their offspring will have these traits |
observations regarding natural selection and population, reduction, size, resources, and variation | All organisms reproduce exponentially: create more of themselves (increase total number); Population size tends to remain stable; Resources are limited (e.g. food, space, water, sunlight, etc.); Variation exists within populations (phenotype and genotype --different alleles in different individuals); Much of the variation is heritable (due to genes) |
how is natural selection related to evolution | natural selection = the influence by selective pressure that exists (evolution will not create the 'perfect animal'; evolution edits trait/genes that already exist) |
what is selective pressure and how was it created | any cause that reduces reproductive success in a portion of population (created to make competition between a population) |
what is the theory of evolution | evolution occurs, driven by natural selection (change occurs in the genetic makeup of populations over time, because some heritable traits allow individuals to survive and reproduce better than others) |
what is non-adaptive evolution | evolution NOT caused by natural selection (traits/alleles that do not confer a survival or reproductive advantage = no selective pressure; caused by genetic drift) |
what is genetic drift? In what cases are its effects more or less pronounced | change in allele frequency in a population due to random sampling; in small populations, the chances of an allele being lost are high -> in large populations, the chance of an allele being lost is lower |
what is the founder effect | when a small group of individuals populates a new region (founders may or may not have the same proportions of alleles as the main populations -- rare alleles may be more common, less common, or completely lost) |
what is the bottleneck effect | a natural disaster dramatically and randomly reduces the population size (rare alleles may be more common, less common, or completely lost) |
what is the definition of a biological species | a group of actually or potentially interbreeding organisms that can produce fertile viable offspring |
what is allopatric speciation | speciation that occurs in geographically isolated populations; population split in 2 by colonization of a distant place, a geographical event, or extinction of intermediate populations |
what is sympatric speciation | occurs within a common geographical area; multiple different selective pressures (e.g. how to get different food sources) and a single population favor different traits |
what are fossils | preserved remains of dead organisms |
How do radioactive isotopes behave? How can they behave in fossils? How can they be used to measure the age of a rock/fossil? | unstable --> will decay into common isotopes or a different element at a predictable rate which is slowly (millions/thousands of years); by measuring the amount of radioactive isotopes in a fossil we can calculate how long ago it was formed |
what are transitional fossils? How can fossil records provide evidence of speciation events? what are the limitations of fossil records? | transitional fossils--> a fossil of an organism that share traits with an organism that share traits with an ancestral group with a descendant group |