Ecology Exam 1

Quantitative observations, testable hypothesis

Quantitative observations, testable hypothesis

What makes ecology a scientific study?

descriptive

Ecology approach that relies heavily on observation

functional

Ecology approach using computer models to determine how interactions work

evolutionary

Ecology approach that studies the roles of adaptions in a specie’s function

In an area where all species are not yet known

Where would a descriptive ecologist still be necessary

changes in the frequency of genes in a population from generation to generation

What is evolution?

mutation, genetic drift, gene flow, nonrandom mating, natural selection

What forces can cause evolutionary change?

genetic drift

evolutionary change resulting from a random loss of alleles in a population

founder effect

A few individuals split off from a population to form a new colony with only a portion of alleles from the original population

genetic bottleneck

chance events that may kill off many individuals at random

gene flow

migration of genes between populations

nonrandom mating

sexual/artificial selection that chooses for particular traits

mutations

new genetic combinations that arise over time, some helpful, most not

variation, excess of individuals, limited resources, heritable traits

What is necessary for natural selection to occur

The ability to survive and reproduce.

What does fitness mean in the context of ecology?

better

Gene frequencies will change with generations, reproducing more of the genes that lead to _________ reproductive success

adaptations

traits that increase fitness

sexual dimorphism

male and female of a species look different

directional

What type of selection was the drought that caused larger beaks to have higher survival and reproduction after the drought?

stabilizing selection

selection where both extremes are selected against (favors the mean)

yes

can directional selection go different ways at different times?

no

does evolution have an end goal?

aposematic coloration

Warning colors for predators

Batesian mimicry

When a species that is not dangerous mimics the coloration of a dangerous species to trick predators

Caley and Schluter

Who wrote a paper about incremental evolutional evolution of mimicry in reef fish

Used fish models at different levels of mimicry. Observed approaches and attacks from fish.

What did Caley and Schluter do in their study of mimicry?

The umbrella of protection allows similarity to reduce predation. The pattern doesn’t need to be perfect to work. Mimicry can work incrementally.

What results did Caley and Schluter find in their study of mimicry?

birth weight in humans, hatching time in geese, bird clutch size

What are some examples of stabilizing selection?

disruptive selection

selection that favors the extremes but not the mean

fish adapted to the top vs. the bottom of a lake

examples of disruptive selection

color is an indicator of fitness

Why would female guppies choose a colorful male mate?

John Endler

Who performed the study on the mating preferences of Amazon guppies?

amount of coloration

What was gaudiness a measure of in Endler’s guppie study?

predation, sexual selection

What opposing forces caused guppies in different rivers or different locations on the same river to have different degrees of gaudiness?

they were more inconspicuous

What did Endler find about the guppies in the rivers with more dangerous predators?

they were gaudier

What did Endler find about the guppies in the rivers with few predators?

Coevolution

Two (or more) species apply selection pressure to each other, reciprocally. Ex:bees and flowering plants

Arms race

The escalation of adaptations and counter-adaptations between two or more parties. Ex: squirrels immune to poison ivy

kin selection

Helping out your close relatives helps spread your own genes.

genetic forces, changing environment, limited time/energy, historical constraints

constraints on the “perfect adaptation”

physiology/ short term factors

What are proximate factors

evolution and selection/ long term factors

What are ultimate factors?

determinate layers

Can only lay a set amount of eggs in a year

Indeterminate layers

can lay more eggs when necessary, no set amount

cost-benefit analysis

Lack’s hypothesis to determine the ideal clutch size for birds based on the number they can provide with food

it depends on the species, the one with the highest benefits compared to costs

What is the optimum clutch size?

If they raise 6 eggs they will not survive until the next year to do it again

Why do house wrens raise 3-4 birds rather than 6 when they are capable of it?

behavior

The ways organisms respond to each other and particular cues in the environment

1 and 2 proximate, 3 and 4 ultimate

Which of these are proximate/ultimate?

•How is a behavior produced?

• How does the behavior develop?

• What is the adaptive value of the behavior?

• What is the evolutionary history of then behavior?

maximize

Adaptive behaviors ________ fitness

benefits-costs

how do you measure relative benefits

territory

a defended area

protects resources, attracts mates

What are benefits of having a defended territory?

no, that decreases their fitness

do territorial animals want to fight?

the spot on the x-axis where the distance between the cost and benefit lines is the largest

how do you find the optimum size on a cost-benefit graph?

based of flower availability

How do hummingbirds adjust their territory size?

no

Is food evenly distributed in time and space?

food distribution, nutrition, ease of catching and processing

What factors influence optimal foraging?

animals need energy to survive and reproduce

Why does natural selection favor optimal foraging?

λ

Variable for the rate at which a certain type of prey is encountered

T

Variable for time spent foraging

E

Variable for energy units per prey item

h

Variable for handling time

the amount of time it takes to acquire and eat something, includes potential damages

what is handling time?

high encounters, high energy, low handling time

based on the prey switching threshold equation shown, should predators chose prey that is high or low in encounters, energy, and handling time

a predator should switch to alternative prey

what happens when the prey switching threshold equation becomes false?

handling time is fixed, prey value is only based on energy, all prey of a type are identical

What are some assumptions of the prey switching threshold equation?

Increased Foraging Efficiency, Reduced Predation, Increased access to Mates, Help from Kin \n

potential benefits of group living

Competition for food, susceptibility to disease spread, attraction of predators, loss of paternity from promiscuity, brood parasitism, loss of individual reproduction

potential costs of group living

community

multiple species living together

Births, deaths, immigration, emigration

Core processes that impact population

density

# of individuals per m^2

biomass

grams per m^2

trees, people, deer

examples of organisms that would be measured by density

fungi, clonal plants, bacteria

examples of organisms that would be measured by biomass

population model

Mathematical equation that approximates/predicts patterns in nature, based on scientific observations

1+b-d

how do you find lambda in a the simple population growth model

per capita death rate (died/ alive at beginning)

what is d

per capita birth rate (born/alive at beginning)

what is b

lambda

population growth rate variable

All individuals identical, no limiting factors, b&d constant, no immigration/emigration

Assumptions of the simple exponential mathematical model for population growth

16, 2

A cyanobacterium fissions every 6 hours. \n • At the end of the day, how many cyanobacteria will it become? \n • What is the population growth rate?

2

A clone of Lycopodium (ground pine) weighed 500 g two years ago and now weighs 2000 g. \n • What is its population growth rate? (λ)

9.15

The water boatman, Notonecta, lays about 30 eggs per year but only 30% of these hatch to maturity. About 15% of breeding adults survive to breed again. \n • What is the population growth rate? (λ)

semelparous animals

 reproduce once in life then die

• Big bang reproduction

iteroprous

reproduce multiple times over life

annuals

plants that complete life cycles in 1 year

biennials

 special case of plants that live only 2 years reproducing only 2nd year

survivorship curve where most mortality happens at old age

type 2

survivorship curve with constant mortality over life cycle

type 3

survivorship curve where a few individuals live a long life but there is high mortality when young