Ecology Ecology is the study of interactions among organisms and between organisms and their environment.

Ecology: Levels of Organization Individual Population Community Ecosystem Biome Biosphere

Ecological Methods Observing: simple or complex; first step in asking ecological questions Experimenting: test hypotheses in a lab or in the field Modeling: gain insight into complex phenomena (global warming)

Ecological Niche Niche defines an animal’s lifestyle… habitat nutrition foraging territory Niche includes everything an animal does or uses in order to survive.

Ecology: Energy Flow Every organism needs energy. Sunlight is the main energy source for life. Less than 1% of sunlight is used by organisms. Where does the rest of the sunlight go? Photograph courtesy philip.greenspun.com

Ecology: Energy Flow photosynthesis: use of light energy to produce carbohydrates autotrophs make their own food. autotrophs are producers Why?

Ecology: Energy Flow sunlight is not available to all organisms chemosynthesis: use of chemical energy to produce carbohydrates most chemotrophs are bacteria and algae are they autotrophs? Deep sea hydrothermal vent worms

Ecology: Energy Flow autotroph: produces its own food heterotroph: acquires energy from other organisms What is a producer? What is a consumer? Are heterotrophs producers or consumers? consumers: primary secondary tertiary quaternary

Ecology: Energy Flow heterotrophs are consumers herbivores eat plants carnivores eat meat omnivores eat plants and meat insectivores eat _____________ detritivores feed on remains decomposers break down organic matter Where are decomposers in a food chain?

Ecology: Feeding Relationships Energy flows through an ecosystem in one direction (arrows) from the sun or inorganic compounds to producers to consumers. Food chain: diagram that shows simple feeding relationships. Trophic level: each step in a food chain All food chains start with a producer.

Feeding Relationships: Food Chain squid (tertiary consumer) small fish (secondary consumer) zooplankton (primary consumer) algae (producer)

Students be careful! Remember: the arrow shows the direction energy flows in an ecosystem. In this example, the Leopard seal eats the penguin and as a result, gets the energy.

Ecology: Feeding Relationships A food web is a network of complex feeding relationships that connects multiple food chains. If one species is lost from a food web, all other species are affected.

Terrestrial Food Web

Aquatic Food Web

My Favorite Food Web Matt Pendley, Buford High School, Buford, GA

Ecology: Community Interactions Competition: when organisms try to use a resource in short supply at the same time and same place.

Ecology: Community Interaction Predation: when one organism captures and eats another organism.

Ecology: Community Interaction Symbiosis: any relationship in which two species live closely together.

Ecology: Symbiosis Mutualism: when both species benefit from the interaction. In this example, the sea anemone is cleaned by the clown fish, who in turn is protected by the anemone’s stinging tentacles.

Ecology: Symbiosis Commensalism: when one species benefits from the interaction and the host species is unaffected. The leafy plant is an epiphyte, growing on another plant only for support.

Ecology: Symbiosis Parasitism: interaction in which one organism benefits and the other organism (host) is harmed. Does the host die as a result? Asian tiger mosquito

Ecological Pyramids: Energy Pyramid (energy flow in a community) each trophic level represents a different group of organisms in a food chain about 10% of the energy available at each trophic level is transferred to organisms at the next trophic level energy is lost as heat and in life processes

Ecological Pyramids: Biomass Pyramid biomass is the total amount of living tissue expressed as grams of organic matter per unit area biomass pyramid represents the potential amount of food available at each trophic level normally the greatest biomass is at the base

Ecological Pyramids: Numbers Pyramid based on the numbers of individuals at each trophic level some number pyramids look like biomass & energy pyramids, some do not in this example, the oak tree has a large amount of energy and biomass, but it is only one organism

Laws of Ecology All things are interconnected. Everything goes somewhere. There’s no such thing as a free lunch. Nature bats last. Ecology: A Pocket Guide by Ernest Callenbach