UNIT 14
ECOLOGY
ECOLOGY
A. Overview 1. Ecology
a. “The investigation of the total relations of the animal both to its inorganic and organic environment.”
b. how living things and nonliving things affect one another c. it’s roles:
1. to study the relationships between organisms and their environment
2. predict what would happen if some factors were changed 3. recommend steps to change an environment or the
ECOLOGY
2. Ecosystem
a. all the living things and nonliving factors and their interactions within
a limited area b. 2 different parts:
1. abiotic factors
a. all the non-living factors in an ecosystem (that affect life) b. radiation – heat, light
c. winds (land) or currents (aquatic) d. soil
e. topography
ECOLOGY
2. biotic factors (how living things are organized)
a. all the living factors in an ecosystem b. levels:
1. individual – a single organism
2. population – all the members of the same type of living thing within an area
3. community – different populations living together
4. ecosystem – total system of interactions between living organisms and nonliving things and factors within a limited area
ECOLOGY
3. Food Chains and Food Webs (how living things interact with one another)
a. food chain
1. nutritional relationships between organisms in an ecosystem b. food web
ECOLOGY
c. trophic levels:
1. all energy comes from the sun / geothermal vents 100%
2. primary producers – harness energy(autotrophs) 10% 3. primary consumers – eat producers (heterotrophs) 1%
4. secondary consumers – eat primary consumers (heterotrophs) .1%
5. tertiary consumers – eat secondary consumers (heterotrophs) .01%
6. quaternary consumers – eat tertiary consumers (heterotrophs) .001%
ECOLOGY
d. at each trophic level, 10% of energy is lost thru heat e. detritivores – break down dead organic material
ECOLOGY
4. species interactions a. neutralism
1. no direct relationship between species, no connection. b. competition
1. two populations that inhibit each other because they depend on the
same limited resource. c. *predation
ECOLOGY
d. amensalism
1. when one population is inhibited or harmed by a second population
and the second population is not affected by the first. e. *parasitism
1. a parasite depends on its host and often causes it harm. f. *commensalism
1. if one population benefits from a second population and the second
population is neither harmed nor helped. g. *mutualism
1. both populations benefit from their relationship.
ECOLOGY
B. The Biosphere
1. biosphere – thin shell around the earth in which all known physically living
things exist
a. as deep as 4,000 m below the earth’s surface – bacteria found there
b. 9.7 km (6 miles) in ocean trenches – some species are found
c. some species fly high in the sky, others live on top of mountains
2. interactions in the biosphere
a. habitat – the area where a type of organism lives
1. the physical environment and the biotic community in which
ECOLOGY
b. niche – how the organism affects the ecosystem
1. what an organism does and how it fits into and affects its habitat
2. includes both the biotic and abiotic factors
c. habitat an organisms address, its niche its occupation 3. matter and energy in an ecosystem
a. the quantity of available energy lessens with each level of a food chain
b. biogeochemical cycles
ECOLOGY
4. limiting factors
a. factors that in some way limit the growth or existence of an organism
b. sunlight, CO2, nutrients, temperature, food shortage, lack of space, disease,
predators, habitat destruction, etc… 5. population changes
a. birthrate and death rate impact a population’s size b. immigration – movement of individuals into an area c. emigration – movement of individuals out of an area
6. carrying capacity – the maximum population size that can be sustained in a given
ECOLOGY
7. population growth – birth + immigration > death + emigration
a. exponential growth – occurs when a population increases by a constant
ECOLOGY
7. logistic growth – grows nearly exponentially at first but then stabilizes at the
maximum population size that can be supported indefinitely by the environment
ECOLOGY
C. Changes in the Biosphere
1. All living things constantly change to maintain the homeostasis necessary
for their living conditions
2. ecological succession – predictable changes that occur in a biotic
community over a period of time
a. primary succession – an ecosystem develops gradually from bare
rock
b. secondary succession – the progression of biotic communities in
which soil and plants are already in place
1. example – grasses, clovers grass, shrubs trees
D. Major Biomes of the World
Biome Wate
r Temperature Soil Plants Animals
Desert Almost
None Hot or cold Poor Sparse – succulents (cactus), sage brush
Sparse – insects,
arachnids, reptiles and birds (often nocturnal) Tundra Dry Cold Permafrost
(frozen soil) Lichens and mosses Migrating animals Taiga
(coniferous forest)
Adequat
e Cool year-round Poor, rocky soil Conifers Many mammals, birds, insects, arachnids, etc. Temperate
deciduous forest
Adequat
e Cool season and warm season
Fertile soil Deciduous trees Many mammals, birds, reptiles, insects, arachnids, etc. Grassland Wet season, dry season
Warm to hot (often with a cold season)
Fertile soil Grasses (few or
no trees) Many mammals, birds, insects, arachnids, etc. Tropical
rain forest Very wet Always warm Poor, thin soil Many plants Many animals Swamp Very wet Warm
MAN IN THE BIOSPHERE
A. Pollution
1. man’s placing into the environment substances, that because of either
their nature or their abundance, make a significant negative change in
the environment.
MAN IN THE BIOSPHERE
a. biodegradable
1. pollutants that the environment can break down and return to the
normal cycling of substances a. sewage
b. paper
MAN IN THE BIOSPHERE
a. nonbiodegradable
1. pollutants that stay in their original form and cannot be broken apart in the environment
a. glass b. metal
c. many chemicals
MAN IN THE BIOSPHERE
B. Climate’s Large Effect on Biosphere
1. climate – average or typical weather for a given area over a relatively long period
of time
2. weather – the state of the atmosphere
3. incoming solar radiation – sunlight strikes Earth directly at the Equator, but at angles near N & S pole
a. tropical regions receive 2.5 times as much radiation as polar regions b. results in increased productivity in tropical regions
1. productivity – measure of energy that producers are able to store
MAN IN THE BIOSPHERE
Man’s Ecological Future
MAN IN THE BIOSPHERE
What would you like to do about how you affect the environment?
