Chapter 3: The Biosphere What is ecology?

Ecology Ecology – the study of interactions among organisms and between organisms and their environment Interdependence – dependence of every form of life on other living things and natural resources (air, water, land) in its environment

Levels of Organization Biosphere – largest, portions of planet where life exists (land, H 2 O, air) –8 km above to 11 km below Biome – group of ecosystems with same climate (temp. and rainfall) Ecosystem – collection of all organisms in a particular place together with the abiotic (physical) environment.

Levels of Organization Community – groups of different populations that live together in a defined area. Population – groups of individuals of same species in same area. Species – group of organisms so similar that they can mate and produce fertile offspring.

Levels of Organization

Biotic and Abiotic Factors Biotic – living –Plants, Animals,Mold, Fungi, Bacteria, Protist Abiotic – Non living –Sunlight, soil, wind, water, temperature Habitat – the area where an organism lives; includes both biotic and abiotic factors.

3.2 Energy - Autotrophs (producers) Can trap light energy to produce food (organic molecules) –Plants –Some protists –Some bacteria Photosynthesis – captures solar energy and converts it to chemical energy 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Chemosynthesis – Chemical energy used to produce carbohydrates SUN

3.2 Energy - Heterotrophs (consumers) Can’t trap energy directly; must acquire it from other organisms –Herbivores – plants –Carnivores – animals –Omnivores – both –Detritivores – remains of dead plants & animals –Decomposers – break down organic matter

3.3 Energy Flow in Ecosystems Food Chains and Food Webs

3.3 Food Chains and Food Webs SUN AutotrophsHeterotroph 1.Food Chain – energy trapped by producers passed on when organisms eat and are eaten 2.Food Web – relationship more complex than a chain

Trophic Levels and Ecological Pyramids Trophic Levels – each step in a food chain/web Ex: producers, then consumers Ecological Pyramids – shows relative amount of energy at each level (10% rule) Biomass – total amount of living tissue within a trophic level

Trophic Levels and Ecological Pyramids

3.4 Cycles of Matter *Recycle Matter*

Carbon Cycle Photosynthesis – uses CO2 from atmosphere –Happens in the CHLOROPLAST Respiration – returns CO2 to atmosphere –Happens in the MITOCHONDRIA

Carbon Cycle

The Carbon Cycle 1.Volcanoes, respiration, fossil fuels, and decomposition add CO2 to atmosphere. 2.Plants take CO2 and make carbohydrates 3.Plants are eaten by animals and carbohydrates are passed through the food chain. 4.As the animal breathes and eventually dies and decomposes CO2 is return to atmosphere. Decomposing Fox

Water Cycle

1.Water enters the atmosphere by: Evaporation – water changes from a liquid to a gas Transpiration – Evaporation through leaves 2.As water rises it cools condenses into tiny droplets that form clouds. 3.Droplets return to Earth as precipitation. 4.Water enters the rivers, ground water, ocean or plant roots to restart cycle. Making Clouds

Nitrogen Cycle

1.Nitrogen gas makes up 78% of atmosphere 2.Nitrogen Fixation: bacteria take nitrogen gases and turn it into ammonia, nitrite, and nitrate. 3.Plants and animals use nitrate to make amino acids. 4.Animal dies and decomposes returning nitrates to the soil. 5.Denitrification: other bacteria convert nitrates into nitrogen gas. Fertilizer Runoff

Nutrient Limitation Primary Productivity – the rate at which organic molecules are created by producers If nutrients are in short supply, they are called LIMITING NUTRIENTS Ex: Nitrogen is often limiting in water; if there is suddenly as input of N (fertilizer runoff), organisms can grow rapidly (Algal Bloom)

4-2 Niches and Community Interactions

4.2 The Niche Niche – Where and How something lives; its role –Habitat is the organism’s address –Niche is the organism’s occupation

Community Interactions 1.Competition Organisms compete for resources Ex: Food, Mates, Shelter Competitive Exclusion Principle – no 2 organisms occupy same niche at same time. 2.Predation One organism (predator) captures and feeds on another (prey). Battle at Kruger Lake

4.2 Community Interactions 3.Symbiosis Mutualism – both benefit Ex: Flowers & insects Egrets & Alligators Clown Fish & Sea Anemone Commensalism – one benefits, the other is not helped nor harmed Ex: Barnacle & Whale Parasitism – one benefits, other is harmed Ex: tapeworms, fleas, ticks, lice

Keystone Species – essential to the balance of an ecosystem, change in their population can cause a dramatic change in the community. Dung Beetle Otters and Kelp

4.3 Ecological Succession Ecological Succession - change in an ecosystem 1.Primary Succession – no soil (volcanic eruption or bare rock) –first to appear are “pioneer species” Ex: Lichens 2.Secondary Succession – Soil Exists (wild fires, clear cutting, plowed for farming) 3.Succession in a Marine Ecosystem – happens when a large whale dies and sinks to the bottom 4.Climax Community – fairly stable, mature, dominant community established after succession.