BSC 2011 Exam 3 - Ecology Review

define ecology

scientific study of interactions between organisms and their environment

come up with an example of how ecological interactions affect evolutionary processes

the coevolutionary race between rough-skinned newt and common garter snake involving TTX toxin and resistence

• predator-prey interactions lead to escalating adaptations overtime

describe different levels of organization in ecological systems

1. organism: individual living thing

2. population: group of individuals of the same species in the same area

3. community: all populations of diff species living in the same area

4. ecosystem: community of organisms + abiotic factors

5. biosphere: sum of all ecosystems on earth

basic steps in the Scientific Method

1. observation

2. question

3. hypothesis

4. experiment

5. analysis

6. conclusion

Coriolis forces

the curving of moving objects caused by earth’s rotation

• creates prevailing winds from East to West

• objects curve right in the NH and left in the SH

ITCZ

air moving upward at the equator creates the ITCZ

• creates rainforests from the moisture

• creates deserts at 30S and N where cold, dry air descends

• doldrums from convergence of trade winds creating calm winds at equator

Hadley cells

cold air moves toward equator from N and S, then warms and moves upward at the doldrums, creating precipitation at the equator (rainforests) and air becomes cooler and drier as it moves back N and S (deserts)

drivers of regional climate

• sunlight

• movement of the planet

• atmospheric and oceanic circulation

climate vs weather

climate: trends in atmospheric behavior over a relatively long time period

weather: day-to-day variations in the state of the atmosphere

Greenhouses gases and the greenhouse gas effect

greenhouse gases are gases that absorb and emit infrared/heat radiation

• e.g. CO2, CH4, N2O, O3, CFCs, H2O

the increase in these gases causes climate change through warming of the Earth’s surface and lower atmosphere

anthropogenic global warming

the consequences of human activities that contribute to climate change

• increase in extreme weather events

• ocean acidification

• increased water in atmosphere over ocean

• warmer oceans

• melting of sea ice

biome def

a distinct physical environment inhabited by ecologically similar organisms with similar adaptations

factors that determine biomes

• physical environment: soils, substrate, disturbances

• climate and climatic variability: temp, precip, seasonality

interpreting a walter climate diagram

• N hemisphere starts with Jan, S hemisphere starts with Jul

• ecosystems are water limited if temp line exceeds precipitation line

• white zones denote frozen conditions- effective growing seasons must be above 0C

Tropical rainforest

• very consistent high temps and precipitation

• highest species diversity

• very high nutrient cycling

deserts

• found at 30N and 30S

• arid environment- consistent temp and precipitation

• plant thorns, think leaves, cuticle for UV

• no big mammals, little animals burrow

tundra

• 3 types: arctic, antarctic, and alpine

• short growing season, severe winter, permafrost (carbon sink)

• very low consistent temp, low precipitation (falls as snow)

• veg: lichen, moss, heath

Boreal forest

• largest terrestrial biome

• soil is poor and acidic

• severe winter

• lots of precipitation as snow

• abundant conifers

Temperate forest

• distinct winter season (frost and snow) and summer season (warm and moist)

• soil is fertile

Temperate grassland/shrubland

• hot summer and cool winter

• precipitation high in winter, dry in summer

• few trees, lots of grass

Tropical Savannah/Seasonal Forest

• temperature varies little

• distinct wet/dry seasons

• trees and grass condominant

Define a population and population ecology

a group of interbreeding animals of the same species in same area

• study of births, deaths, and dynamics regulating a population

Understand concepts of density and dispersion

• density: number of individuals per unit of area

• dispersion: pattern of spacing among individuals

Estimate population size using mark-recapture formula

1. capture animals

2. mark animals and release

3. recapture

4. do math

#marked x total # captured/ #marked found in second capture

life history

traits making up an organism’s schedule of reproduction

• age at first reproduction

• frequency and duration of reproduction

• total number of offspring produced

• life expectancy

tradeoffs

survivorship types

• type 1: flat at start, drops at older ages

• type 2: intermediate constant mortality over life span

• type 3: drops at start and flattens for few surviving individuals

Describe the processes and basic mathematics underlying exponential population growth

BD model: change in pop. over change in time = b - d

Describe both the exponential and logistic models of population growth and their assumptions

exponential growth is in an idealized environment

• rmax stays same, n increases

logistic growth incorporates carrying capacity

Be able to describe and contrast biotic and abiotic factors that control population size

biotic controls: parasitism, disease, predation, competition

• density dependent

abiotic controls: temp, moisture, storms

• density independent

Describe and identify different types of species interactions

• mutualism: both species benefit

• predation/parasitism/herbivory: one species benefits the other is harmed

• competition: both species are harmed

• commensalism: one species benefits, the other is unaffected

• amensalism: one species is harmed, the other is unaffected

Define competition and competitive exclusion

competition: any use or defense of a limiting resource by an individual that decreases its availability to others

• can use resources differently through partitioning

competitive exclusion: two species cannot coexist indefinitely on the same resource

• can’t occupy same niche