honors biology 2010-2011. what is ecology? eco comes from greek word “oikos” – house -logy...
TRANSCRIPT
Chapter 13: Principles of Ecology
Honors Biology 2010-2011
What is Ecology?Eco comes from Greek word “oikos” –
house -logy comes from “logos” – study of Ecology means “study of the house” as
coined by Ernst Haeckel
Ecology – the study of interactions among organisms (plants and animals) and their environment
Levels of Organization (page 397 Figure 13.2)From individual to global: Organism—individual living thing (ex.
Lion)
Levels of OrganizationPopulation—group of same species that live in
one area (ex. Pride of lions)
Levels of OrganizationCommunity—collection of interacting
populations (ex. Lions, antelope, zebras, elephants, grasses, etc…)
Levels of OrganizationEcosystem—interactions of biotic and
abiotic factors in an areaBiotic factors—living or once living
things (ex. Animals, plants, microorganisms, etc…)
Abiotic factors—nonliving things (ex. Sunlight, temperature, soil, etc…)
Levels of OrganizationBiome—regional or global community of
organisms which is usually characterized by the climate conditions and plant communities that thrive there
Section 13.2In an ecosystem, each living thing depends
on an array of biotic factors and abiotic factors in the ultimate web of life.
A single change in that web can lead to minor or major changes.
A keystone species is one that has an unusually large effect on its ecosystem. (ex. Beaver) (ex. Killing too many deer during hunting season)
Section 13.3 Energy in Ecosystems (page 406)Autotrophs—“self feeder”Heterotrophs—“different feeder”
Producers —obtain energy from the sun (by photosynthesis pg 407) or chemicals (by chemosynthesis pg 407) and convert it to a useable form of energy (like food, sugar, carbohydrates)
What kind of feeders are these?
Section 13.3*All ecosystems depend on producers,
because they provide the basis for the ecosystem’s energy.
Consumers—get their energy by eating other living or once-living organisms (like autotrophs and/or other heterotrophs)
What kind of feeders are these?
Types of consumers: (page 409)Herbivores—obtain energy from eating
plantsOmnivores—obtain energy from eating
plants and animalsCarnivores—obtain energy from eating
animals
Types of ConsumersDetritivores—obtain energy from eating
detritus or dead organic material (ex. Earthworm)
Decomposers—obtain energy from breaking down organic matter (dead) into simpler molecules that can be more easily absorbed by decomposers and by other organisms
Why would they by important? Important in an ecosystem to return vital
nutrients back into the environment
Section 13.4 Food Chains and Food WebsTo show energy transfer between different
species, a food chain can be constructed. A food chain is a linear sequence that links
species by their feeding relationships. Matter and energy move through an ecosystem
by use of arrowsExample:
autotroph→heterotroph→decomposer*Heat energy is lost in each step
Trophic LevelsTrophic levels are the levels of nourishment
in a food chainExample: producer→herbivore→carnivore
Chain has 3 trophic levels
1st trophic level producer (base)2nd trophic level primary (1’) consumer
(herbivore), first order3rd trophic level secondary (2’) consumer
(omnivore/carnivore), second order4th trophic level tertiary (3’) consumer
(omnivore/ mostly carnivore), third order (top level)
Energy flows through an ecosystem in ONE direction
Food web- links all the food chains in an ecosystem
The stability of any food web depends on the presence of producers, as they form the base of the food web
Section 13.6 Pyramid ModelsEach level in the food chain contains much
less energy than the level below it. The sun continually pumps new energy into the system to continue life.
Only about 10% of the available energy is transferred to the next trophic level. Maximum number of organisms in a food chain is 5 because of energy loss.
Where does the rest of the energy go?
An energy pyramid compares energy used by producers, primary consumers, and other trophic levels (in units of kilocalories, kcal) see figure 13.17 on page 418
A biomass pyramid provides a picture of the mass of producers needed to support primary consumers, the mass of primary consumers required to support secondary consumers, and so on.
A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem.
Biomass pyramids and pyramids of numbers may occur in an inverted, or upside down formation. What might this indicate about that ecosystem?