The study of living organisms in the natural environment How they interact with one another How the interact with their nonliving environment

The study of living organisms in the natural environment How they interact with one another How the interact with their nonliving environment

ENERGY At the core of every organism s interactions with the environment is the need for energy to power life s processes. Energy cannot be created, just used and transferred from different sources.

Energy starts with Autotrophs: Organisms which can make their own complex, energy rich, organic molecules (e.g. photosynthesis) All plants are autotrophs Also known as primary producers

Then it moves to Heterotrophs: organisms who must obtain complex, energy rich, organic compounds from other organisms. All animals are heterotrophs Also known as Consumers: Specifically; herbivores, carnivores, and omnivores

And it is recycled by. Detrivores:Heterotrophic organisms who ingest dead organic matter. (e.g. earthworms, woodlice, millipedes, vulchers) Also known as decomposers

Energy Flow through an Ecosystem Producers Consumers Decomposers Energy is transferred from one trophic level to the next and lost as heat. 10% Rule of Energy transfer: Only about 10% of the energy in one trophic level is transferred to the next level. The rest is lost as heat.

Tertiary Consumers 10 kcal/m²/year Secondary Consumers Primary Consumers Producers 10,000 kcal/m²/year

Food Chain Single pathway of energy

Food Web Interconnecting food chains. Arrows demonstrate the pathway of energy. Arrow must point to the consumer.

Community Interactions Symbiosis: Interaction between two or more organisms

Predator-Prey When one organism (the predator) captures and feeds on another animal (the prey)

Both organisms benefit Mutualism

Parasitism One organism benefits, the other is harmed.

Commensalism One organism benefits other is unharmed. the

Characteristics of Populations Geographic distribution: the area inhabited by a population Example: 1 million square kilometers occupied by migrating whales in the Pacific Ocean Density: the number of individuals per unit area Example: 150 bullfrogs per 3 square kilometers Growth Rate: the rate at which a population changes Example: In some developing countries, a baby is born every 3 seconds.

Population Growth Birth Rate: The rate at which individuals are born into the population Death Rate: the rate at which individuals leave the population by dying.

Calculating Population Growth Birth Rate- Death Rate = Population Growth Ex: 700 turtles born in 1980 350 turtles died in 1980 700 turtles born 350 turtles died= 350 turtles (Population Growth in1980)

The point at which the growth slows or stops is known as the population s carrying capacity or the largest number of individuals that environment can support.

Limits to Growth Limiting factor: something that causes a population growth to decrease.

Density Independent Affect all populations in similar ways, regardless of population size. (Abiotic Factors) Unusual weather, natural disasters, seasonal cycles, and certain human activities- such as damming rivers and clear cutting forests.

Density Dependent A limiting factor that depends on population size. (Biotic Factors) Competition: the more individuals living in an area the fewer available resources Predation: populations are often controlled by the predator-prey relationship. Parasitism and Disease: parasites can limit the growth of a population.

1. A group of organisms of the same species that interbreed and live in the same place a. Community b. Population c. Organism d. Species

2. A collection of interacting populations a. community b. population c. organism d. species

3. Interactions between biotic populations and abiotic factors in a community a. community b. biosphere c. population d. ecosystem

4. A single living thing a. community b. organism c. population d. ecosystem

5. Which is a biotic factor? a. temperature b. water c. soil d. plants

6. Organisms that use energy from the sun to make their own food are a. producers b. consumers c. carnivores d. omnivores

7. Animals that consume autotrophs for their food and energy are a. producers b. carnivores c. herbivores d. omnivores

8. Animals such as foxes that consume other animals for their food and energy a. producers b. herbivores c. omnivores d. carnivores

9. Animals such as bears that consume both plants and other animals for food and energy a. producers b. carnivores c. herbivores d. omnivores

Ecological Succession The replacement of one community by another in a single place over a period of time

Causes for Succession Primary Succession: occurs on a brand new surface that has never seen life. Ex: Island after a volcano eruption Coastal sand dune

Secondary Succession Occurs on previously occupied land after a disturbance (anything that results in the removal of the existing communities) Ex: Fire, flood, deforestation, or competition with another organism

Pioneer Species: first organism to appear in succession. Characterized as fast growing, rapidly reproducing, small in size and easily dispersed. Ex: Lichen- can survive in extreme conditions Late successional species: characterized as slow growing, large in size, and longer lived. Climax Community: stable end community of succession