Chapter 21: Section 1, pg 705

Chapter 21: Section 1, pg 705• Key concepts: What needs are met by an

organism’s environment?• What are the two parts of an organism’s

habitat with which it interacts? What are the levels of organization within an ecosystem?• Key terms: organism, habitat, biotic factor,

abiotic factor, photosynthesis, species, population, community, ecosystem, ecology

Organisms and habitats• An organism is a living thing. • Organisms need to obtain

food, water, shelter to live

• Habitats are environments that provide areas for organisms to grow and live.

• Organisms live in different habitats because they have different requirements for survival.

Biotic factors

• An organism interacts with both living and nonliving parts of its habitat. • Biotic factors are the living parts, like

animals, plants, and insects.

Abiotic factors• Are the nonliving parts of a habitat. Water, sunlight, oxygen, temperature,

and soil.• Water – all living things need water. • Sunlight – needed for photosynthesis (plants make their own food in

chloroplasts) which fuels plants to grow. Animals then eat the plants.• Oxygen – most living things require oxygen• Temperature – temperatures determine what kind of organisms live there• Soil – mixture of rocks, nutrients, air, water, and decaying remains of

organisms

Levels of organization• Species – group of organisms similar enough to mate and have

offspring that can also reproduce• Population – all the members of one species in a particular area• Communities – all the different populations that live together in an

area• Ecosystems – the community of organisms that live in a particular

area, along with their nonliving surroundings.

In other words:• The smallest level of organization is

a single organism, which belongs to a population that includes other members of its species. The population belongs to a community of different species. The community and abiotic factors form an ecosystem.

And, finally• Ecology – the study of how living things interact with each other and

with their environments.

Please complete:• Section 1 assessment in your notes, 1abc, 2abc, 3abc • I will check it at the start of our next science period.