chapter 40
ecology
study of homes
population ecology
focuses on factors affecting how many individuals of a species live in an area
community ecology
deals with the whole array of interacting species within a community
ecosystem ecology
emphasizes energy flow and chemical cycling among the various biotic and abiotic components
landscape ecology
deals with arrays of ecosystems and how they are arranged in a geographic region
global ecology
the biggest, examines the influence of energy and materials on organisms across the biosphere
bodies of water effects on climate
ocean currents heating or cooling, coastal regions wetter than inland regions
mountains influence on climate
air flow over land, moisture distribution
biomes
major ecological associations that occupy broad geographic regions of land or water
terrestrial biomes are defined by
vegetation type
aquatic biomes are defined by
physical environment
climate aspects that affect the distribution of biomes
annual mean precipitation
annual mean temperature
climograph shows how these vary to create biomes
general features of terrestrial biomes
vertical layering of vegetation, major physical or climatic features, dominant vegetation
tropical forest features
high temp and precipitation, vertically layered plants compete for light, the highest diversity
desert
can be cold or hot, low precipitation, low widely scattered vegetation, plants developed denfense against herbivores
chaparral
rainy winters dry summers, shrubs small trees fire adapted
temperate grassland
moderate precipitation summers are wet winters are dry, grazers prevent trees, burrowing animals are common
northern coniferous forest
cold winters, large range in annual temperature, some depend on fire to regenerate, plant diversity is low
temperate broadleaf forest
moderae precipitation, humid summers, deciduous trees, birds migrate in winter
tundra
low precipitation and temperature, veg is mostly herbaceous, frost prevents root growth
wetlands
induated by water, highly productive, humans destrpy by drainage, pollution, filling
lakes
light decreses as move deeper, thermocline (warm on top, cold on bottom) nutrient rich, humans destroy by runoff
streams and rivers
clear cold water, downstream is warmer, humans pollute water quality
intertidal zones
submerges twice daily, upper strata experience more exposure to air and greater variations in temp and salinity
coral reefs
aquatic version of rainforest humans destrpy by ocean acidification and pollution
oceanix pelagic zone
covers 70 percent of earth, mixed by wind currents
marine benthic zone
sea floor
interactions between organisms and the environment limit
the distrubtion of species
dispersal
movement of individuals away from centers of high population density or from their area of origin
species transplants
organisms that are intentionally or not relocated from their original distribution
biotic factors that affect the distribution of organisms
interactions with other species, predation, competition
abiotic factors that affect the distribution of organisms
temperature, water and oxygen, salinity, sunlight, rocks and soil
density
the number of individuals per unit area or volume
population
a group of indiviuduals per unit area or volume
dispersion
the pattern of spacing among individuals within the boundaries of the population
mark and recapture method
way of estimating population sizes
density relies on
immigration, emmigration, births, deaths
common patterns of dispersion
clumped, uniform, random
clumped dispersion
individuals aggregate in patches, influenced by resource availibility and behaviour
uniform dispersion
individuals are evenly dispersed, influenced by social interactions such as territoriality
random dispersion
individuals are spread independently, occurs in the absence of strong attractions or repulsions
demography
study of vital stats of a population and how they change over time
survivorship curves 3 types
low death in early years, high in older years
death rate is constant
low death in higher years and high in younger years
reproductive rates focus only on
females
intrinsic rate of increase
rate of reproduction is at its maximum
growth is close to exponential when population is small and resources are plentiufl
true
logistic growth model
per capita rate of increase declines as the carrying capacity is reacahed
population dynamics are heavily influenced by
life history traits and population density
k-selection
selects for life history traits that are sensitive to population density
r-selection
selects for life history traits that maximize reproduction
metapopulation
a regional group of connected populations of a species that fluctuate in size and stability over time