13.1 Ecologists Study Relationships

Review Vocab:

• Organism• Population

New Vocab:• Ecology• Communit

y• Ecosystem• Biome

KEY CONCEPT Ecology is the study of the relationships among organisms and their environment.

13.1 Ecologists Study Relationships

Main Idea 1: Ecologists study environments at different levels of organization.

• Ecology is the study of the interactions (relationships) among living things, and between living things and their surroundings.– Studying how life interacts within the

biosphere.• Scientists used to study each organism

separatelyas if they existed in isolation.

13.1 Ecologists Study Relationships

Levels of Organization(There are 5 levels)

However, now scientists study nature on different levels, from

local to a global scale. This organization reveals the complex

relationships found in nature.

13.1 Ecologists Study Relationships

OrganismOrganism

First level:• An organism is an individual

living thing, such as an alligator.

13.1 Ecologists Study Relationships

OrganismOrganism

Population

Population

Second level:• A population is a group of the

same species that lives in one area.• What can cause populations

to change?

13.1 Ecologists Study Relationships

Limiting Factors of Limiting Factors of PopulationsPopulations– Birth & death rates

eventually balanceFactors: Disease,

food, predators, climate, space, mates

• Carrying Capacity: Greatest number of individuals that a population can sustain– What stage is the human

population in?

13.1 Ecologists Study Relationships

Human Population: Fast Growth Stage • How have

humans extended our carrying capacity?

• Farming• Medical

innovations• Clean

water• Public

assistance

13.1 Ecologists Study Relationships

OrganismOrganism

Population

Population

Community

Community

Third level:• A community is a group of

different species that live together in one area.

13.1 Ecologists Study Relationships

OrganismOrganism

Population

Population

Community

Community

Ecosystem

Ecosystem

Fourth level:• An ecosystem includes all of the

organisms as well as the climate, soil, water, rocks and other nonliving things in a given area.

13.1 Ecologists Study Relationships

OrganismOrganism

Population

Population

Community

Community

Ecosystem

Ecosystem

BiomeFifth level:• A biome is a major regional or

global community of organisms characterized by the climate conditions and plant communities that

thrive there.

13.1 Ecologists Study Relationships

• Climate factors that affect biomes: sun, rain, topography• Climate

determines life.

Basically, a biome is a large area with distinct climate, plant, and animal life.

13.1 Ecologists Study Relationships

KEY CONCEPT Every ecosystem includes both living and nonliving factors.

New Vocab:• Biotic• Abiotic• Biodiversit

y• Keystone

Species

13.1 Ecologists Study Relationships

Main Idea 1:An ecosystem includes both biotic and abiotic factors.

• Biotic factors are living things, like:

– plants– animals– fungi– Bacteria• Bio = Life

•If something has life, then it is living.

plants

13.1 Ecologists Study Relationships

• Abiotic factors are nonliving things, like: – moisture– temperature– wind– sunlight – soil– rocks

moisture

sunlight

•A = Without Bio = Life

•If something does not have life, then it is not living.

•The balance of these factors determines what can live in a particular environment.

13.1 Ecologists Study Relationships

Main Idea 2:Changing one factor in an ecosystem can affect many other factors.

An ecosystem is a complex web of connected biotic and abiotic factors.

• Biodiversity is the assortment, or variety, of living things in an ecosystem.– The amount of biodiversity in an ecosystem

depends on many factors.– Rain forests have more biodiversity than other

locations in the world, but are threatened by human activities.

– Why is this?

13.1 Ecologists Study Relationships

• A keystone species is a species that has an unusually large effect on its ecosystem.– Because there are complex relationships

within an ecosystem, a single change (a few broken strings in a web) in biotic or abiotic factors could have a variety of effects.

keystone

What would happen if the keystone in the arc was missing?

13.1 Ecologists Study Relationships

• Here is an example of a Keystone species and how they form and maintain a complex web of life.

creation ofwetlandecosystem

increased waterfowlPopulation

increased fishpopulation

nesting sites for birds

keystone species