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Flashcards in Exam 3 Deck (56):
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Evolution

Change in a population overtime

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Natural Selection

The process by which organisms better adapted to their environment tend to survivie and produce more offspring

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5 agents of evolutionary change

Natural Selection
Genetic Drift
Founder Effect
Bottleneck
Gene Flow
Sexual Selection

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Genetic Drift

A random change in allele frequencies in a population

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Fixation

The reduction of genetic variation due to genetic drift

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Founder Effect

Small number of individuals leave a population and become the founders of a new area - usually having a different allele frequency than the original population

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Bottleneck

Reduction of a population (usually caused by death) leaving a small fraction of the original population intact, this smaller population will usually have different allele frequencies than those that died

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Gene Flow

Migration into or out of a population will change allele frequencies

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Sexual Selection

A form of natural selection that depends on an individuals ability to obtain a mate

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Fitness

A measure of the relative amount of reproduction of an individual with a particular phenotype compared to the reproductive success of an individual with a different phenotype

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3 important elements to an organisms fitness

Environment
Fitness measured relative to other genotypes or phenotypes in the population
Depends on an organisms reproductive success compared to the other organisms in the population

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Stabilizing Selection

Individuals with intermediate phenotypes are most fit

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Disruptive Selection

Individuals with extreme phenotypes experience the highest fitness, and those with intermediate phenotypes have the lowest

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Species

Population that is capable of interbreeding to poduce healthy fertile offspring

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Reproductive Barriers

Prezygotic and Postzygotic barriers

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Prezygotic Barriers

Prevent mating between different species (this happens before the fusion of sperm and egg)

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Temporal Isolation

Mating times differ (some like mornings, some like nights, etc)

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Habitat Isolation

Living in different habitats that dont allow organisms to cross paths easily

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Behavioral Isolation

No sexual attraction (you looking for a buff guy not a bitch like nik)

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Mechanical Isolation

Wrong organs to fuck with (my nigga doesnt have a penis that goes into a vagina)

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Gametic Isolation

Egg and sperm fail to fuse to make zygote

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Postzygotic Barriers

Barriers that occur after the hybrid zygote is formed

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Hybrid Sterility

The hybrid cannot reproduce

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Mechanisms of Speciation

Making a new species

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Altruistic Behavior

Behaviors that come at a cost to the individual doing the behavior while benefiting the recipient (jumping infront of a bullet to save someones life)

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Female investment to reproduction

Produces larger gamete (egg) (by making larger gamete, the female has already invested more towards reproduction because this takes more energy to do)

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Male investment to reproduction

Produces the smaller, usually mobile gamete

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Tactics for getting a mate

Courtship rituals
Gifts
Control resources
Looks

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Tactics for keeping a mate

If the offspring benefit from having a father, the male is more likely to provide parental care

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Mate Gaurding

Copulatory plugs-break off penis into her so no other penis can get in

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Monogamy

One male one female

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Polygyny

1 male bunch of females

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Polyandry

1 female and bunch of males

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Sexual Dimophism

Differences between male and female (size, aggressiveness)

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Sexual Monomorphism

Male and females look the same

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Ecology Levels

Individual
Population
Community
Ecosystems
Biosphere

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Individual

Organism

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Population

A group of individuals of the same species living in a defined area

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Community

Consists of two or more populations of diff species living in the same area

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Ecosystems

Consists of a community of living things interacting with the physical aspects if their environment

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Biotic Factors

Living things in an ecosystem

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Abiotic Factors

Nonliving things in an ecosystem

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Biosphere

Consists of all the earths ecosystems containing living species

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Limitations for species to live

Physical factors
Interactions with other species
Geographical barriers

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Interactions between species

Competition
Predation
Parasitism
Commensalism
Mutualism

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Competition

Two species competing for resources

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Competitive exclusion

When one species wins the competition with another species excluding it

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Predation

Predators seek prey to survive

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Parasitism

One species benefits at the expense of another (without killing it for as long as possible)

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Commensalism

One species benefits but the other is unharmed

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Mutualism

Both benefit from the interaction

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Genetic Biodiversity

The collection of genes within a population

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Causes of biodiversity loss

Habitat destruction
Invasive species
Overharvesting
Pollution
Climate change

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Population growth

Most species cannot handle expionential growth

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Density dependent

Events that depend on a population size to occue

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Density independent

Events that dont depend on the population of a species to occur