Chapter 2 Principles of Ecology

Organisms and their Environment What is Ecology? Definition - Scientific study of interactions among organisms and their environment Combines information and techniques from many scientific fields… chemistry, physics, geology, mathematics, among others.

Levels of Organization in Ecology Organism Population Communities Ecosystems Biosphere (Biome)

Organism An organism is an individual living thing, such as an alligator. An organism is an individual living thing, such as an alligator.

Organism Population A population is a group of the same species that lives in one area.

Organism Population Community A community is a group of different species that live together in one area.

Organism Population Community Ecosystem An An ecosystem includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area.l as the climate, soil, water, rocks and other nonliving things in a given area.

Organism Population Community Ecosystem Biome A biome is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there.

Biotic factors are living things. Biotic factors are living things. – plants – animals – fungi – bacteria An ecosystem includes both biotic and abiotic factors.

Abiotic factors are nonliving things. Abiotic factors are nonliving things. –moisture –temperature –wind –sunlight –Soil

Changing one factor in an ecosystem can affect many other factors. Changing one factor in an ecosystem can affect many other factors. Biodiversity is the assortment, or variety, of living things in an ecosystem. Biodiversity is the assortment, or variety, of living things in an ecosystem. Rain forests have more biodiversity than other locations in the world, but are threatened by human activities. Rain forests have more biodiversity than other locations in the world, but are threatened by human activities. – Only 7% of the world’s surface – 50% of the world’s plant and animal species

Habitat The place where an organism lives out its life It can find food, shelter, protection, and mates for reproduction It is not necessarily a geographic area; for instance a viruses’ habitat is the body of its host.

Niche Role or position a species has in its environment – this includes all its interactions with the biotic and abiotic environment – – How it survives – – Food & shelter – – Reproduction

Living Relationships Symbiosis – a relationship in which there is a close and permanent association among organisms of different species

Commensalism A symbiotic relationship in which one species benefits and the other is neither harmed nor benefited

Mutualism A symbiotic relationship in which both species benefit – – Hummingbird & foxglove – – Ants and acacia tree m4 m4

Parasitism A symbiotic relationship in which one organism benefits at the other’s expense – – Tomato worm – – Tick/mosquito – – Tapeworm

Nutrition and Energy Flow Producers provide energy for other organisms in an ecosystem. Producers provide energy for other organisms in an ecosystem. Producers - energy from non-living resources. Producers - energy from non-living resources. Producers are also called autotrophs… why ? Producers are also called autotrophs… why ? Basis for EVERY ecosystem! Basis for EVERY ecosystem!

The Producers Autotrophs – Can make their own food; they do it by using energy from the sun or energy stored in chemical compounds – – They do not need a living source of energy – – Can reduce CO2 to make organic compounds for biosynthesis and create a store of chemical energy

The Consumers Heterotrophs – can not make their own food so must feed on other organisms Include organisms that feed only on autotrophs, organisms that feed solely on other heterotrophs, and organisms that feed on both autotrophs and heterotrophs

Scavengers Heterotroph They don’t kill their food Eat animals that have already died

The Decomposers Break down the complex compounds of dead and decaying plants and animals into simpler molecules that can be more easily absorbed

Consumers are not all alike. Consumers are not all alike. –Herbivores eat only plants. –Carnivores eat only animals. –Omnivores eat both plants and animals. –Detritivores eat dead organic matter. –Decomposers are detritivores that break down organic matter into simpler compounds. carnivore decomposer

Food chains and food webs model the flow of energy in an ecosystem.

Food Web Expresses all the possible feeding relationships at each step in a community More realistic model than food chain because most organisms depend upon more than one species for food

A food chain is a model that shows a sequence of feeding relationships. A food chain links species by their feeding relationships. A food chain links species by their feeding relationships. A food chain follows the connection between one producer and a single chain of consumers within an ecosystem. A food chain follows the connection between one producer and a single chain of consumers within an ecosystem. REMEMBER…Arrows show the direction the ENERGY moves!! REMEMBER…Arrows show the direction the ENERGY moves!! DESERT COTTONTAILGRAMA GRASSHARRIS’S HAWK

The Water Cycle

Life depends upon water, its cycled through stages; constantly moving between atmosphere and Earth Water vapor in air condenses in the air and forms clouds and when clouds are full it rains filling oceans/streams/lakes and evaporation starts

The Carbon Cycle

CO 2 forms in the air

The Nitrogen Cycle

The Phosphorous Cycle