8.11B: Investigate how ecosystems

and populations in an ecosystem

depend on and may compete for

biotic and abiotic factors

Make a new title page: “Ecology”

Glue in a new table of contents after this

title page

An ecosystem is all the living (biotic)

and nonliving (abiotic) things that

interact in an area

What is the difference between an abiotic

factor and a biotic factor?

Abiotic factor are the non-living components of

the environment:

* sunlight, temperature, moisture, wind or

water currents, soil type, and nutrients

Biotic factors are the living components of the

environment:

* plants, animals, fungi, algae, and

bacteria

Can you always tell if it is biotic or abiotic?

Let’s test your knowledge!

Answer Q1-2 now.

Work with a

partner to fill in

the Venn diagram

before time is up

What are your thoughts or questions now?

Abiotic factors are especially important to

the survival of plants that form the base of

the food web for all other organisms.

Common Abiotic factors are:

1. Sunlight

2. Temperature

3. Water

4. Nutrients/elements

5. Space

6. soil

These interactions are important for survival

Ex. Chloroplasts in a plant cell allows them to

interact with sunlight.

Draw a Venn diagram in your notes – base it on

the picture below. What do we title the center?

Marine ecosystems – these organisms depend

on the amount of sunlight, water temperature,

wave action and water pressure at various

levels of the ocean.

It is the original energy source for

almost all ecosystems

Plants capture this energy and put it

into food webs.

In order to survive, plants need

sunlight and space

Many adaptations allow plants to

survive in various amounts of light,

water, temperatures, and soil types.

Kelp adapts to salinity

level, ocean currents,

living under water

cacti adapt to lack of

water, predators, poor

soil conditions

Venus fly trap adapts to

lack of nitrogen (poor

soils in rain forests)

Carrying capacity – the number of individuals

that can obtain food, shelter, and water from

the environment in a given period of time

This applies to both plants and animals

What do you know

about:

White tailed deer

overpopulation in

Texas?

Any area can only sustain a certain amount of individuals before

there is damage!

Limiting factors are

things that prevent a

population from growing

any larger

Food, water, light,

living space,

temperature,

competition, disease,

etc.

What are they?

Tell me your thoughts…

Biotic factors also include food chains and

webs where some organism might share food

sources.

This “sharing” isn’t actually sharing, it’s

competition for resources! We will come

back to this concept later.

There are three major types

of interactions among

organisms in ecosystems:

Competition

Predation

Symbiosis

Competition occurs between

organisms when they try to make

use of the same limited resources

Competition occurs between:

Members of the same species

Among species with similar

niches

How do these examples to the

right compete?

An organism’s particular role, or how it

fits into an ecosystem, is called its niche

A niche is carved out when species

compete

Many organisms are adapted to overcome

competition by resource partitioning:

They feed at different times of day

Or at different levels of the same tree

Resource partitioning - helps competing species

share a resource and develop a niche for

themselves in an ecosystem.

Predation - An interaction in which one

organism hunts and kills another for food

The organism that does the killing – predator

The organism that is caught - prey

Predators have adaptations that help them

catch and kill their prey.

Cheetahs can run very fast to catch prey

Jellyfish have poisonous tentacles to paralyze prey

Owls have big eyes to see at night

Prey have adaptations to help them

avoid being caught

Camouflage

Protective coverings

Warning coloring

Mimicry

False coloring

Predation can have a major effect on

population size

If predators are very effective, the

result is a decrease in the prey

population

In turn, a decrease in the prey

population will result in a decrease in

the predator population

A close relationship between two different species that benefits at least one of the species

There are three types of symbiotic relationships:

Mutualism

Commensalism

Parasitism

Benefits of Symbiosis:

Food

Transportation

Cleaning

Protection/Shelter

Reproduction

One species benefits (+) and the other is unaffected (0)

Commensalism means “at the table together”

Barnacles and whales

Both species benefit

Giraffes and Oxpeckers

One living thing gains (+)

considerably at the expense

(-) of the other

Host – the organism that the

parasite lives on or in – it will

be harmed

Parasite – the organism that

benefits

Maggots in My Head

Reef Symbiosis

In symbiosis, at least one member of the pair benefits from the relationship.

Commensalism Mutualism Parasitism

One benefits

One benefits

One benefits

One is

unaffected

Also benefits

One is harmed

Even humans create personal

territories, even temporary ones

in order to have enough space.

Humans tend to space themselves

out when they are close to others

They establish what we might

call “personal territories”

Even in a temporary spot, people (animals) make space. It makes us feel more secure and protected

Area of Room (m2) = Width (m) X Length (m)

Personal Space (m2) =Area of Room (m2)

Number of Students

Think of the classroom as your ecosystem. The edges of the room define your habitat. Calculate the area of the habitat (classroom).

Determine the number of students that live in the habitat (in the classroom). Divide the area of the room into equal amounts of space for each student.

Area of Room (m2) = Width (m) X Length (m)

Think of the classroom as your ecosystem. The edges of the room define your habitat. Calculate the area of the habitat (classroom).

1. Use meter sticks to measure the length (1/2 of the groups do this).2. The other groups measure the width.3. We will take the average for our calculations.

Personal Space (m2) =Area of Room (m2)

Number of Students

Determine the number of students that live in the habitat (in the classroom). Divide the area of the room into equal amounts of space for each student.

How many students do we have?

How big is the room?

How many students are there?

So how much personal space did

everyone get?

It might look

like this