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Bio003 - Lecture 13
UCR Bio003 - Population Evolution
38
Biology
Undergraduate 1
08/26/2009

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Term
What is an adaptation?
Definition
Behavioral, structural, biochemical, physiological
Term
Who is Jean Baptiste Lamarck?
Definition
Suggested that life on Earth evolves
Term
What is Darwin's Theory of Evolution?
Definition
The primary mechanism of evolutionary change producing adaptation of organisms to their environment is natural selection
Term
The study of what suggested that species had changed over time
Definition
The study of fossils
Term
Darwin proposed natural selection as what?
Definition
Mechanism of evolution
Term
Darwin reasoned natural selection as
Definition
Traits that increase their chance of surviving and reproducing in their environment tend to leave more offspring than others
Term
Which evolves? Individuals or populations?
Definition
Populations
Term
Natural selection can amplify or diminish: heritable traits, acquired characteristics, or both
Definition
heritable traits only
Term
Is evolution goal directed? Why or why not?
Definition
No because favorable traits vary as environments change
Term
Examples of natural selection known to occur in nature
Definition
Pesticide resistance, evolution of whales from land mammals, antibiotic-resistant bacteria
Term
What do fossil records show about evolution?
Definition
Organisms have evolved in a historical sequence and provide strong evidence for evolution
Term
what is biogeography?
Definition
The geographic distribution of species, suggested to Darwin that organisms evolve from common ancestors
Term
What is comparative anatomy?
Definition
Comparison of body structures in different species
Term
What is homology?
Definition
Similarity in characteristics that result from common ancestry such as in vertebrate forelimbs
Term
What is comparative embryology?
Definition
Comparison of early stages of development among different organisms
Term
What is molecular biology?
Definition
Comparsion of DNA and animo acid sequences between different organisms
Term
How do fossil record, biogeography, comparative anatomy, comparative embryology, and molecular biology support evolution?
Definition
fossil record - historical record, biogeography - evolve from common ancestors, comparative anatomy - shows similarities in bone structure, comparative embryology - shows similarities in embryos, and molecular biology - shows common DNA
Term
Homologies indicate patterns of descent which then can be shown by what?
Definition
An evolutionary tree
Term
What is a gene pool?
Definition
Total collection of gene in a population at any one time
Term
What is an microevolution?
Definition
Change in the relative frequencies of alleles in a gene pool over time
Term
What can alter allele frequencies in a population? (Also known as the three main causes of evolutionary change)
Definition
Natural selection, genetic drift, and gene flow
Term
Do mutations have any effect on the gene pool?
Definition
No, they have little effect because they are rare and random
Term
When does natural selection alter allele frequencies?
Definition
When individuals differ in their survival and reproductive success
Term
What is genetic drift?
Definition
Change in the gene pool of a population due to chance
Term
What is the bottleneck effect? And what does it leads to a loss of?
Definition
phenomenon where the performance or capacity of an entire system is limited by a single component; leads to a loss of genetic diversity
Term
What is the founder effect?
Definition
loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population; usually when a few individuals colonize a new habitat
Term
What is gene flow?
Definition
The movement of individuals or gametes/spores between populations and can alter allele frequencies in a population
Term
What is stabilizing selection?
Definition
a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value (favors intermediate phenotypes versus extreme phenotypes)
Term
What is directional selection?
Definition
occurs when natural selection favors a single phenotype and therefore allele frequency continuously shifts in one direction
Term
What is disruptive selection?
Definition
Selection that simultaneously favors individuals at both extremes of the distribution
Term
What does sexual selection lead to?
Definition
Phenotypic differences between males and females
Term
What is Sexual dimorphism?
Definition
Distinctly different appearances between genders
Term
What is intrasexual competition?
Definition
Competition for mates, usually by males; individuals of one sex (usually females) are choosy in picking their mates.
Term
What do diploidy and balancing selection preserve?
Definition
Genetic variation
Term
Diploidy preserves variation by?
Definition
"hiding" recessive alleles
Term
What is balancing selection?
Definition
Selection by maintaining stable frequencies of two or more phenotypes in a population
Term
What is heterozygote advantage?
Definition
Heterozygotes have an advantage over homozygous
Term
Why can't natural selection fashion perfect organisms?
Definition
Selection can only act on existing variation; Evolution is limited by historical constraints; Adaptations are often compromises; chance, natural selection and the environment interact
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