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Evolution Basics
Concepts and Vocabulary
23
Biology
Undergraduate 1
02/10/2014

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Cards

Term
What are the two benefits of evolutionary theory?
Definition
1. It allows us to understand how life diversifies.
2. It helps us make predictions.
Term
Natural selection
Definition
The survival and reproduction of individuals based on variations in traits.
Term
What were Darwin's three major propositions for evolution?
Definition
1. Species change over time.
2. Descent with modification.
3. Natural selection explains the changes in species.
Term
Descent with modification
Definition
Divergent species share a common ancestor and have diverged gradually over time.
Term
Phenotype
Definition
Physical expression of an organism's genes.
Term
Characters
Definition
Features of a phenotype. (ie. eye color)
Term
Traits
Definition
Specific forms of a character. (ie. blue, green, brown eyes)
Term
Genotype
Definition
Genetic sequence that determines phenotypic characters.
Term
Alleles
Definition
Different forms of a gene.
Term
Locus
Definition
Particular location on a chromosome.
Term
What are the three types of questions biologists ask?
Definition
1. Mechanical questions - proximate answers, how does a structure/behavior work?
2. Functional questions - why has a structure/behavior arisen?
3. Historical questions - how has a pattern changed through evolution?
Term
Define biological evolution
Definition
Changes in allele frequencies of groups of organisms (populations) over time
Term
Microevolution
Definition
Casual mechanisms of change, including natural selection, genetic drift, mutation, and gene flow.
Term
Macroevolution
Definition
Refers to the divergence of species over long periods of time.
Term
Describe Jean-Baptiste Lamarck's contributions.
Definition
He provided early evidence for evolution in 1809. He believed that species are created spontaneously and lineages persist indefinitely. He proposed inheritance through acquired characteristics.
Term
Describe Georges Cuvier's contributions.
Definition
He was a paleontologist who studied comparative anatomy and thus established extinction as a fact. He believed in the fixity of species, but unlike Lamarck, he didn't think that species persisted indefinitely.
Term
Describe Carl Linnaeus' contributions.
Definition
He developed binomial nomenclature as a way of naming and classifying organisms. Like Cuvier, he believed that species were fixed in form and could never change.
Term
Describe Aristotle's contributions.
Definition
He proposed the theory of causes, which attempts to explain the "fit" of organisms to their environments. He also developed a scale of being, or so-called ladder of life that implies a linear progression in evolution.
Term
Vestigial traits
Definition
Functionless or rudimentary versions of some body part that has a function in a closely allied species.
Term
What are the four tenets of natural selection?
Definition
1. There is variation among individuals.
2. At least some of the variation is heritable.
3. Organisms differ in their ability to survive and reproduce.
4. Survival and reproduction are nonrandom.
Term
What's the difference between proximate and ultimate explanations?
Definition
Proximate explanations place emphasis on anatomical, physiological, or biochemical features. Ultimate explanations place emphasis on understanding the casual reasons why traits evolve.
Term
Define August Weismann's contributions?
Definition
He provided evidence against Darwin's theory of pangenesis and the theory of inheritance of acquired characteristics. He proposed the germ-plasm theory instead, which says that inheritance occurs in gametes as opposed to somatic cells.
Term
Pangenesis
Definition
Every separate part of an organism reproduces itself individually.
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