ecology - bio 152

ecology

scientific study if the interactions of organisms and their environment

abiotic interactions

physical world and organism

biotic interactions

interrelations with members of other species and individuals of the same species

ferdinand magellan

1840-1521, first voyage around globe

alexander von humboldt

17867-1859, first studies of relationships between organisms and their environments

organismal ecology

individual survival and reproduction, unit of natural selection

population ecology

population dynamics, unit of evolution

community ecology

interactions among species

ecosystem ecology

flow of energy and matter

landscape eology

landscape level ecological patterns

global ecology

global processes

charles darwin

1809-1882, population growth and source limitation, heritable variation, differential survival and reproduction as a mechanism for natural selection and biological evolution

ernst haeckel

1834-1919, coined the term oekologie, for the relationship of animals to their environment

sir arthur george transley

1871-1955, coined the term ecosystem and urged a more experimental approach to the study of ecology

compare and contrast: ecology and environmentalism

environmentalism is social and political movement, ecology is a science, ecology can inform environmentalism

what impacts an organisms success in an area?

dispersal, behavior, biotic factors, abiotic factors

rebirth of natural history

recognizing the importance of observation

what is wind caused by?

differential heating of Earth's surface

(the cycle of hot air rising as it expands, then cold air falling, and then cold air heating to continue the cycle)

major determinants of global climate

1. spherical shape of the earth; uneven heating

2. revolution of the earth around the sun on a tilted axis (constant tilt of 23.5 degrees)

what is the single best explanation for what causes seasons on earth?

the earth is tilted on its axis

seasonal variation in daylength is affected by…..

latitude. places near the 0 have the leas variation in day length during the year

lake stratification

when there are layers in temperature depending on the depth in a body of water.

(ie. top of water is 22 degrees, but the layer below is 18 and the layer below that one is 8)

lake turnover

when all of the water from the bottom and top of the water is mixing. this makes the entire body of water a consistent temperature no matter the depth

what allows for most vegetation?

water availability and temperature (more warmth and precipitation, more vegetation/life)

lake zonation

smaller aphotic and pelagic zone, has a littoral and limnetic zone. photic zone is slightly bigger, benthic zone less steep

marine (ocean) zonation

benthic zone steeper, aphotic and pelagic zone much bigger. photic zone slightly smaller. has oceanic, neritic, and intertidal zone. also has abyssal zone and continental shelf

topography

physical features of earths surface contribute to global temperature patterns. (ie. temperature declines with increasing elevation)

evapotranspiration

the sum of evaporation directly from soils and water bodies plus the amount transpired by plants

biome

a large, distinct region of the world that is defined by its similar climate, landscape, and specific communities of plants and animals

tundra biome

cold, short days in winter, close to north pole, very little tundra, temp and precipitation are low, mosses, low shrubs, wolves, foxes

north facing slope

more vegetation, more moisture

south facing slope

less vegetation, more sunlight so more dry and warm, has more drought

alpine biome

similar to tundra but lacks permanent ice and temps range more. has wildflower and grassses, mountain goats, llamas

taiga biome

moist forest, summer brings rain, birds, insects more abundant, elk, moose, caribou, bears, lynx, wolves, foxes

temperate coniferous forest biome

warm summers, mild winters, abundant precipitation in winter, insects abundant, ferns, grasses, red cedar, redwoods,

deciduous forest biome

moderate seasonal temp variation, precipitation all year long, faces most human disturbance, maples, oaks, insects, birds, lizards, snakes

temperate grassland biome

blue stem and buffalo grass, lack of precipitation, bison, horses, ferrets, badgers, foxes

desert biome

little precipitation, lizards, snakes, coyotes, hawks

chaparral biome

a little more precipitation, usually falls in a period of 2-4 months, small trees and shrubs, acacia, olives

savanna biome

tall grass, warm, rain is seasonal, antelope, zebra, hyenas, wild dogs

tropical rainforest

most diverse, has much precipitation and warm, trees grow tall, birds, snakes, lizards, bats

population

individuals of one species simultaneously occupying the same general area, utilizing the same resources, and influenced by similar environmental factors

population ecology

study of how biotic and abiotic factors influence the density, disrtibution, size and age structure of populations

high elevation in land leads to…

more diversity!

rain shadow

as air rises over the mountain, it cools, releasing its moisture as precipitation. once over the mountain, the air descends, warming and taking up more moisture. that is the rain shadow

what habitat is warmer in the northern hemisphere?

lower elevation, lower latitude, north facing slope

in southern hemisphere, north facing slope gets more sunlight

in northern hemisphere, south facing slope gets more sunlight

northern wisconsin has…

northern mesic forest, northern dry mesic forest, bog, and pine barrens

southern wisconsin has,,,,

southern mesic forest, oak savana, and prairie

population density

number of individuals per unit area or volume

population change is affected by

deaths. emigration, immigration, and births

mark recapture

scientific method used to estimate the size of a population by capturing, marking, and then recapturing individuals. assuming the ratio of marked to unmarked animals in the 2nd sample is the same as marked animals in the 1st sample population size, N. N=(# total caught in recapture (2nd sample))/(# recaptured that have marks (2nd sample))x(# marked (1st sample))

mark recapture assumptions

population has not changed in size between sampling time, which means that there are no or very little births, deaths, immigration, or emigration. usually means short time between sampling

patterns of dispersion in population

random, clustered, uniform

demography

allows us to predict and understand changes in populations. important factors are age structure and sex ratio. important terms are fecundity (birth rate), mortality (death rate), generation time (time from individual birth to generation of offspring), and cohort (a group of the population that shares a common feature, like birth year)

life table

formal demographic analyses of populations arre based on this type of data set, which summarizes vital rates

survivorship curve

type 1 curve is the human curve-high survivorship over time, type 2 curve is straight diagonal and the bird curve-survivorship decreases at a constant rate, type 3 is a plant curve-many die at the beginning of their life

life history traits

traits that affect an organisms schedule of reproduction and survival

semelparity

expend energy in a single large reproductive effort, then die

iteroparity

produce fewer offspring at a time, and do so repeatedly

model

models are simplified representations of the real world that help us understand and predict ecological patterns

conceptual models

diagrams, flow arrows, useful for thinking and hypothesizing

quantitative models

equations, useful for making predictions

why do we use models?

simplify complex systems to focus on key processes, help us test ideas and make predictions, generate hypothesis we can check in nature

parameters for population growth

N=population size

B=number of births

D=number of deaths

delta=change

t=time

population size equation

delta(N)/delta(t)=B-D

per capita birth rate

b=B/N

per capita death rate

d=D/N

whatg is r?

per capita rate of increase

intrinsic rate of increase

when nothing limits the population growth, the population will grow at its maximum possible growth rate

exponential population growth

dN/dt=rN, if r increases, the curve gets steeper, r can be negative in which the population will decrease until it goes extinct

assumptions of the exponential model

no immigration or emmigration, constant r (b-d);which means unlimited resources, no age size or genetic structure (all individuals are functionally equivalent), and continuous growth without time lags

when do populations grow exponentially?

when invading or colonizing a new or highly favorable environment, when rebounding from a massive crash, when they develop a novel adaptation to cope with their environment, or at the beginning of bounded population growth when a population size is low

limitation of exponential growth

exponential growth model forms the cornerstone of population density. even though no population can increase exponentially forever, all populations have the potential for exponential growth

logistic population growth

what happens when resources are limited. K is a number, a particular population size. it represents the maximum number of individuals that could be supported by the local environment in the long term

logistic growth equation

dN/dt=rN((K-N)/K). assumes that the rate of change in N declines as N increases. N=population size, r=per capita intrinsic growth rate (maximum), K=carrying capacity

note that we have been referring to N as the population size

we sometimes work with a number within a given space, this is defined as population density

((K-N)/K)

this feedback term introduces density dependence. the rate of growth of the population is dependent on population density, relative to a carrying capacity

what is the predicted relationship between population size (x-axis) and the feedback term (y-axis)?

a constant negative slope

density dependent growth

when the population gets higher, then the growth rate reduces and then the population reaches a plateu

density dependent regulation

can affect deaths or births or both, predation, inter- and intraspecific competition, disease, and territoriality

density independent regulation

fire, severe weather, earthquakes, volcanic eruption, pollutiion

r-selection/strategist:density independent selection

reproduce early in life, reproduce at rates approaching rmax, many offspring and few live to reproduce, type III curve, in unpredictable environment

k-selection/strategist:density dependent selection

reproduce late in life, few offspring and many live to reproduce, type I curve, in predictable environments close to carrying capacity

in nature, the r/K strategies are a continuom

its a continuum, not two buckets. most organisms dont fit neatly, there is no good or bad strategy, the theory is historically useful but oversimplified

metapopulation

a collection of connected subpopulations with regular or intermittent gene flow between geographically seperate units; population of populations. if a subpopulation dies, migration can restore or establish subpopulations. we no longer focus on the persistence of any particular population; instead we try to understand the fraction of all population sites that are occupied, interaction of sink and source populations

source population

birth rates > than death rates, surplus individuals can migrate to new locations

sink population

birth rates < than death rates, the population would disappear if not replenished by resources

hyperbolic

higher growth rate, higher population size, example of human population over the years

demographic transition

1) birth and death rates are both high, and the population remains at equilibrium. 2) death rate declines, but birth rate remains high, so population growth rate rises. 3) birth rates drop and death rates stabilikze, making the population growth rate drop. 4) both birth and death rates are low, and the population is at equilibrium again. 5) in very high wealth countries, birth rates may rebound

concept of carrying capacity

must consider consumptive habits + changes due to innovation and technology, ecological footprint: the amount of land and water area required by an individual to produce the resources it consumes and to absorb its wastes, including carbon emissions