I. Populations (Chap 36.1-7)A. Size

1. smaller populations risk extinction2. population growth is limited

a. carrying capacity = the maximum number of individuals an area can supportb. is a dynamic value

- limiting factors: space, water, light, nutrients3. growth slows as carrying capacity is reached

4. adaptationsa. r-selection life history

- favors exponential growth- early reproduction- high mortality- offspring- no parenting- many weed species and insects

b. K-selection life history- later maturity and onset of reproduction- produce few but well-cared-for offspring- fits larger terrestrial vertebrates

B. Density1. number of individuals per unit area2. density-independent effects on population growth

a. affect growth rateb. effects are independent of population size

- weather, natural disaster

3. density-dependent effects:- mainly due to increased competition as population grows

3. density-dependent effects:- mainly due to increased competition as population grows- behavioral changes, migration

3. density-dependent effects:- mainly due to increased competition as population grows- behavioral changes, migration- spreading of disease through a dense population

C. Dispersion patterns1. scatter of organisms in the “range” area2. clumped pattern (most common in nature)3. uniform pattern (territoriality)4. random pattern (scatter by currents)

II. Competition (Chap 37.1-3)A. Niche

1. how an organism uses its available resources2. an organism’s “biological role”

B. Habitat (the place where an organism lives)C. Intraspecific competition

- between individuals of the same species

D. Interspecific competition 1. different species competing for the same resources2. competitive exclusion principle:

- two very similar species competing for the same resources cannot coexist in the same place- one will be slightly more efficient and out-reproduce the other

III. Coevolution and Symbiosis (Chap 37.4-5)- life relationship between different kinds or organisms- lichens, mycorrhizae, N2-fixing bacteriaA. Commensalism

1. one species benefits, with benign effect2. barnacles growing on whales3. birds and cows

B. Mutualism 1. both species benefit2. flowering plants and pollinators

B. Mutualism 1. both species benefit2. flowering plants and pollinators3. carpenter ants and aphids

C. Parasitism 1. parasite benefits while host can ultimately be harmed2. lice, internal parasites3. brood parasitism

IV. Predator-Prey Interactions (Chap 37.5)A. Chemical defenses

1. plants- toxins- bad aromas or tastes- some animals have adapted

2. animals - venoms and toxins- some maintain toxic plant compounds in their tissues

(Monarch caterpillar)

B. Coloration1. warning (aposematic)

- found on many poisonous animals- on many insects that eat toxic plants (Monarch)

2. cryptic coloration (camouflage)

C. Mimicry1. fake warning coloration (Batesian)

- Viceroy and Monarch

Viceroy Monarch

Batesian mimicry

2. resemblance among unrelated poisonous species (Müllerian)- common marking pattern or coloration