Ecology: Biosphere, Ecosystems, and Biotic Factors

• During photosynthesis, plants store energy in the form of sugar.

Biosphere

• The biosphere is the region of the Earth that includes all living organisms, including plants, animals, and bacteria.

Ecosystem

• An ecosystem is a community of living organisms (biotic factors) interacting with the physical environment (abiotic factors).

Population

• A population is a group of organisms of the same species living in the same geographic area at the same time.

Community

• A community contains animals, plants, fungi, and bacteria interacting with each other in a variety of ways.

Biotic

• Biotic refers to living or once-living organisms within an ecosystem.

Abiotic

• Abiotic refers to non-living components or factors within an ecosystem.

Producer

• A producer is an organism that produces its own food using simple inorganic molecules and a source of energy, such as sunlight or chemical energy.

Consumer

• A consumer is an organism that cannot produce its own food and must eat other plants or animals to get energy.

Herbivore

• A herbivore is an organism that only eats plants, e.g., wombats, koalas.

Omnivore

• An omnivore is an organism that eats both plants and animals, e.g., humans, pigs.

Carnivore

• A carnivore is an organism that only eats animals, e.g., Tasmanian devils, tiger snakes.

Decomposer

• Decomposers are fungi or bacteria that break down dead organisms and return matter and nutrients to the abiotic components of the ecosystem.

Detritivore

• Detritivores are scavengers that eat dead organisms, e.g., vultures and earthworms.

Parasites

• Parasites feed on other organisms without necessarily killing them, e.g., ticks, leeches, and fungi that cause tinea.

Trophic Levels

• Understand the difference between trophic levels and levels of consumers.
• 1st trophic level = Producer
• 2nd trophic level = Primary consumer
• 3rd trophic level = Secondary consumer
• 4th trophic level = Tertiary consumer
• 5th trophic level = Quaternary consumer
• Food chains typically have no more than 4-5 trophic levels because only 10% of the available energy is passed on at each stage, and the energy taken in is too small for the animals to survive.

Pyramid of Numbers

• In a pyramid of numbers, each level represents the number of individual organisms consumed by the level above it.

Pyramid of Biomass

• In a pyramid of biomass, each level represents the amount of biomass consumed by the level above it.

Symbiotic Relationships

• Mutualism: Bees populate flowers and get food at the same time.
• Commensalism: Birds nest in trees.
• Parasitism: Mosquitoes and humans.
• Predation: Lions and the hare.