Final Exam Flashcards by Marissa DePolo

What is evolution?

a change in the heritable characteristics of a population over time

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What is evolution by natural selection?

a change in the allele frequency in a population over time

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What are the two parts of cell theory?

all organisms are composed of cells

2. all cells arise from existing cells

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What is a population?

a group of individuals of the same SPECIES living in the SAME AREA at the SAME TIME

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What is a trait?

a distinguishing feature of an organism

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What is natural selection?

the process by which individuals with certain heritable traits are better able to survive and reproduce compared to other members of the population; process by which these individuals are naturally selected

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What is genetic drift?

a change in the frequency of an allele due to a random sampling

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What is gene flow?

is the transfer of alleles from one population to another population through immigration of individuals.

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What is sexual selection?

a type of natural selection that favors individuals who have a combination of heritable traits that are most useful in obtaining a mate

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What is a mutation?

a heritable change in the genetic material of an organism

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What is fitness?

ability to produce offspring relative to other individuals

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What is adaptation? (noun)

heritable trait that increases fitness of a particular individual in a particular environment

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What is adaptation? (verb)

an evolutionary process; alters an organism’s phenotype to enhance its ability to survive in its particular environmental niche

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What is a gene?

a length of DNA that encodes for a protein

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What is an allele?

a version of a gene

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What is a chromosome?

a gene-carrying structure consisting of a molecule of DNA and associated with histone proteins

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What is a genotype?

the genetic makeup of an individual

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What is a phenotype?

the physical characteristics of an organism

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What is a species? (3 parts)

an identifiable group that is distinct in

appearance, behavior and habitat
interbreeds
evolutionarily indépendant

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What is the central dogma?

DNA is transcribed into RNA and RNA is translated into proteins which make up traits

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What is transcription?

the process of making an equivalent RNA copy from a DNA sequence

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What is translation?

when the genetic code is decoded to produce a specific amino acid sequence that encodes for a protein

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What is DNA synthesis?

natural creation of DNA molecules

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What is mitosis?

when the replicated chromosomes are divided for placement into two new daughter nuclei with identical chromosomes

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What is meiosis?

replication results in 4 daughter cells each with half the number of chromosomes from the parent cell

What is the definition of a homozygous?

identical pairs (AA or aa)

What is the definition of a heterozygous?

one dominant and one recessive allele (Aa or aA)

What is gene linkage?

physical association of genes on a chromosome

What are the 5 mechanisms of genetic change?

1. Natural selection 2. Genetic Drift 3. Gene flow 4. Mutation 5. Non-random mating

What are the 4 types of natural selection?

1. balancing 2. directionality 3. stabilizing 4. disruptive

What are the 2 components of non-random mating?

inbreeding and sexual selection

What does inbreeding do?

increase homozygosity

What is an inbreeding depression?

decline in average fitness due to increase homozygosity

How does homozygosity decrease fitness?

too many recessive alleles

What alleles often have a heterozygous advantage?

disease fighting alleles

What is sexual dimorphism?

males are physically distinct from females

What are 4 useful traits for males?

physical beauty, physical skills, parenting skills, and physical strength

What is the bateman-trivers theory?

"eggs are expensive, sperm are cheap"

What is the asymmetry of sex?

females invest a lot in each offspring, males dont

What is the definition of female choice?

if there are equal numbers of males and females, females get to chose their mate

What provides colorful feathers and beaks in birds?

carotenoids

What is male-to-male strength based off of?

weaponry and physical strength

What sex does sexual selection act more strongly on?

males

What does genetic isolation lead to?

genetic diversion

What happens when gene flow is not occurring?

two populations become isolated

What are the 3 factors that isolation allows for independent evolution?

1. natural selection 2. genetic drift 3. mutation

What is speciation?

creation of two or more distinct species from a single ancestral group

What are the 3 methods of new species identification?

1. biological 2. morphospecies 3. phylogenic

What are distinct species defined by?

reproductive isolation

What are the 5 parts of the prezygotic biological species concept?

1. temporal 2. habitat 3. behavioral 4. gemetic 5. mechanical

What are the disadvantages of the biological species concept?

not useful with fossils, asexual organisms, or related species

What is the morphospecies concept?

distinguishing features arise when populations are isolated from gene flow

What is the phylogenetic species concept based upon?

common ancestry

What is a clade?

the ancestral population + all descendants

What does allopatry mean?

the populations become physically separated

What are the two types of allopatry?

dispersal and vicariance

What does sympatry mean?

the populations become close enough to interbreed

What is it called when divergence has occurred and has affected where, when, or how individuals mate?

prezygotic isolation

What is population fusion?

when two populations interbreed and lose distinguishing features

What is reinforcement?

differences between species persist and they remain divergent

What is phylogeny?

the evolutionary history of a group of organisms

What is a phylogenetic tree?

a tree that shows ancestor-descendant relationships

What is a branch of a phylogenetic tree?

the population through time

What is a node of a phylogenetic tree?

when an ancestral population is split into 2

What is the terminal node of a phylogenetic tree?

tip or endpoint of a branch

What are the 3 characteristics that these relationships are based off of?

1. morphology 2. behavior 3. development

What is the phenetic approach?

focuses on similar observable traits

What is the cladistic approach?

focuses on shared ancestry

What is a synaptomorphies?

a trait in a group of species in a clade that doesn't exist in other clades

What is homoplasy?

similar traits evolving independently in different groups

What is homology

similar traits between 2 groups because of a common ancestor

What are adaptive radiations?

when a single lineage produces many descendants that vary

What two triggers trigger adaptive radiation events?

ecological opportunity and morphological innovation