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Topic 6:

Ecology

I. Parts of an Ecosystem

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study of how organisms INTERACT with living and non-

living things in their environment

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Ecological Levels of the Organization of Life

1. Collectively all of the Earth’s

ecosystems make up the biosphere.

2. Ecosystem - populations (biotic

factors) in a community and the

abiotic factors with which they

interact (ex. Biomes)

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3. All the different populations are

combined to form a community

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4. All the organisms of a species that live in the same

area, produce fertile offspring, and compete with

each other for resources (food, mates, shelter, etc.)

make up a population.

•The specific environment in which organisms

live is their habitat.

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5. Organism - any unicellular or

multicellular form exhibiting all of the

characteristics of life, an individual.

•The lowest level of organization

•REMINDER: organisms die, species go extinct

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Ecological Levels

• BIOSPHERE

• ECOSYSTEM

• COMMUNITY

• POPULATION

• ORGANISM

Decreasing

amount of

biotic and

abiotic

factors

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Watch video (pass and user name :bfms

Ecosystems Brainpop (1:39))

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Biotic Factors

ECOSYSTEM

Abiotic Factors

ECOSYSTEM

What makes up an

ecosystem?

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1. BIOTIC FACTORS

• “Bio” means living

• LIVING things in an

ecosystem

• ie.PLANTS, ANIMALS,

BACTERIA

• Can you list the living

things that could live

in this ecosystem?

• Frogs, insects, fish,

hawks, grasses,

bacteria, etc……..

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2. ABIOTIC FACTORS

• When you put “a” in front

of a word it negates it

• Means “NON-LIVING”

factors

• Can you list some non-

living factors that affect

the pond ecosystem?

• WATER, LIGHT,

TEMPERATURE, acidity,

oxygen and nitrogen

levels

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Watch video (pass and user name :bfms

Population Growth Brain Pop Video

(2:27)

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What affects population sizes in an ecosystem?

1. COMPETITION!• Struggle for RESOURCES among organisms

• If no competition, populations would grow INFINITELY(no limit!)

• Competition maintains FINITE (limited) pop’n sizes

• Finite populations limited by LIMITING FACTORS

• CAN BE ABIOTIC OR BIOTIC

INFINITE

GROWTH

FINITE

GROWTH

Comparing Finite and Infinite Populations

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A) ABIOTIC LIMITING FACTORS

✓ Amount and intensity of LIGHT, amount of

WATER, amount of dissolved OXYGEN (lakes,

rivers, etc), ACID level, TEMPERATURE range,

MINERALS available

B) BIOTIC LIMITING FACTORS

•PREDATOR/PREY relationships

• Predators LIMIT prey population sizes by eating them

•Prey limit predator population sizes by dying/being killed

• If too many killed, predators STARVE

• Adapting (SURVIVAL OF THE BEST ADAPTED/FITNESS)

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Let’s take a look…. Effects of Predator/Prey Relationship

AS PREY POPULATION (DECREASES, THE

PREDATOR’S POPULATION DECREASES (THIS

IS A Direct relationship)

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WHAT DO WE CALL IT WHEN A SPECIES REACHES ITS LIMIT?

• EVERY population in an ecosystem has a CARRYING

CAPACITY (K)

• THE # OF ORGANISMS OF A SINGLE SPECIES AN

ECOSYSTEM CAN SUPPORT

• Determined by BIOTIC and ABIOTIC factors

• EX: a fox population is affected by how much it has to eat

(biotic) and also temperature (abiotic)

• Once K is reached, population will remain STABLE

unless major changes in biotic and abiotic factors

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Review Book Worksheet Packet Answers:

pg 1-2

pages 98-106

1) 3

2) 1

3) 3

4) 2

5) 1

6) 1

7) 2

8) 4

9) 2