bio exam 3

what is evolution?

change in allele frequencies over time on a larger scale

what is the smallest unit that can evolve

population

natural selection

relies on differential reproductive success. acts on individuals but the effect is a change in the population

biological fitness

refers to the reproductive success of an organism

modern synthesis (1940’s)

ideas of Darwin and Mendel together.

1. 4 processes of evolution: natural selection, gene flow, genetic drift, mutation

2. traits=genes

3. microevolution

what is microevolution

a change in allele frequency over a shorter time on a smaller scale

intrasexual selection

within same sex

intersexual

between sexes. (male and female)

stabilizing selection

individuals with intermediate traits

directional selection

individuals at one extreme of a trait

disruptive selection

individuals at both extremes of a trait range

gene flow

exchange of alleles between populations

genetic drift

evolutionary equivalent of a sampling error, this error is more problematic in small sample size

bottleneck

type of genetic drift, drop in population size and causes loss of genetic variation

founder effect

occurs when small group of individuals establishes. new reproductively isolated population. often has different allele frequencies than original population

biological evolution

a change in the frequencies of inherited traits in a population of organisms over several generations

Which population would be most likely to survive and evolve with a change in the selective environment?

a large population with high genetic diversity

What did Darwin and Wallace mean when they concluded that species “descend with modification”?

New species arise from previous species.

An intermediate fossil is mineralized evidence of

a species with some similarities to the ancestral group and some similarities to the descendant species.

homologous traits

inherited from a common ancestor, may differ in appearance between species but have a common ancestry

adaptive traits

physical, behavioral, or genetic characteristic

vestigal traits

biological feature that no longer serves its original function

evolutionary traits

heritable characteristic that changes/develops/passed down through generations

common genetic characteristics of all organisms

same genetic code to build proteins, common ancestor, use DNA as hereditary material

who were Godfrey hardy and whilheim Weinberg?

inventors of hardy Weinberg model, came to same conclusion independently

what is the hardy Weinberg model

a populations’s allele and genotype frequencies are constant unless there is some type of evolutionary force acting upon them

what conditions lead to evolution?

mutations, small population size, non-random mating, unequal reproductive success of offspring, immigration/emigration

what conditions are required for population to remain in hardy-weinberg equilibrium

non mutations, random mating, no gene flow, very large population size, no natural selection

allele frequency equation

p+q=1

genotype frequency equation

p²+2pq+q²=1

what is a change in allele frequency

microevolution

biological species concept

potential to interbreed and produce fertile offspring

what are some reproductive barriers

geographic isolation, ecological isolation

morphological species concept

have shared physical traits

ecological species concept

unique role in a community (ecological niche)

phylogenetic species concept

groups that share a common ancestor, genetics

ontogeny

changes in an organism’s morphology throughout its lifetime

species

a group of populations with individuals who have the potential to interbreed and produce fertile offspring

types of prezygotic reproductive barriers

temporal, habitat, mechanical, behavioral, gametic

types of post zygotic reproductive barriers

reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

phylogenetics

The study of the evolutionary relationships between organisms using: morphology (old school method) DNA sequence (new school)

What are phylogenetic trees based on?

The relationships between organisms and their common ancestors

clade

a grouping that includes a common ancestor and all its descendants (living and extinct)

what is the biosphere

all of earths organisms, physical spaces we inhabit, inorganic chemicals

what is ecology

Scientific study of interactions between organisms and their environment

what is climate

predictable, long-term trends, consistent pattern

what is weather

varied pattern, less predictable, follows long-term trends

what is climate determined by

solar radiation, global movements of air and water, major features of Earth’s surface

what are organisms most influenced by

climate

how do we know the climate is changing?

increase in global temperature, decreasing arctic sea ice, increase in ocean heat content

what are the greenhouse gases

absorb heat that radiates away from the earth’s surface, preventing it from being released into space (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, per fluorocarbons, sulfur hexafluoride)

how do greenhouse gases work?

radiation hits earth, portion is reflected back to space, portion absorbed by planet, portion absorbed by greenhouse gases (further warming the earth), some is related to space

where are excess greenhouse gases coming from

human emitted greenhouse gases

mark-recapture equation

marking individuals sampling at time 1/total population size (N) = marking individuals in sampling at time 2/ total captured (marked and unmarked) in sampling 2

G

growth

r

per capita increase

N

population

K

# individuals an environment can support (carrying capacity)

exponential growth

a population increases by a constant rate over time at an interval, j shaped growth curve, occurs in population with no constraints on its resources

what is an example of a population with no constraints?

G=rN

density dependent factors

Lack of space, Lack of food, Increased disease, Stress leading to decreased reproduction, Accumulation of wastes, Predators finding members of the population easy to catch

what leads to zero population growth?

A population that is hovering around the number that the resources in the environment can support or A population in which both the death rate and the birth rates are close to each other

population ecology

how does the red ant population rise and fall throughout the year in the desert

community ecology

how does the red ant species compete for resources with the other ant species

ecosystem ecology

how does sand temperature affect reproduction in various desert ant species

primary consumers

eat producers

secondary consumers

eat primary consumers

What does a community include that a population does not?

multiple species

commensalism

positive, neutral

parasitism

positive, negative

mutualism

positive, positive

predation

positive, negative

competiton

negative, negative

resource partitioning

using resource in different ways, different times, etc