U4L04 Ecological relationships 1

Ecological Relationships

Warm up Questions

Multiple Select

Below is a list of factors in an ecosystem. Select all the abiotic factors.

• Shelter

• Water

• Protists

• Sunlight

• Prokaryotes

Review of Ecological Levels of Organization

Multiple Choice

Which of the following scenario best describes an ecosystem?

• A pack of wolves that live in the same area

• A single protist

• Rabbits hopping around trees burrowing through soil

• Birds, mice, and trees inhabiting the same area

Multiple Choice

An ecosystem is best depicted by which letter?

• A

• B

• C

• D

Carrying Capacity and limiting factors

Carrying Capacity and Limiting Factors

• Carrying capacity (K) - the maximum population size that can be supported in a particular area without destroying the habitat.

• Limiting factors - resources or other factors in the environment that can lower the population growth rate. They determine the carrying capacity of a population.

Examples of Biotic and Abiotic Limiting Factors

- Food

- Nutrients

- Water

- Shelter

- Space

- Mates

- Competition

- Predation

- Disease

- Human Activity

Multiple Choice

What valid conclusion can you draw about the total deer population from the graph shown?

• The total deer population increased gradually over time

• An increase of limiting factors occured in the year 1900

• A decline in food sources occured from years 1750-1900

Types of relationships

Organisms competing for resources.

• Food / Water

• Shelter / Territory / Space

• Mates / Attractions

Competition

​Two organisms that live closely together

• Mutualism

• Commensulism

• Parasitism ​

Symbiosis

​One organisms is a resource for another organsim

• Helps control the size of populations​

Predator / Prey

​

​Types of Relationships

Poll

These types of relationships exist in human populations

• True

• False

Organisms competing for resources.

• Food / Water

• Shelter / Territory / Space

• Mates / Attractions

Competition

​Two organisms that live closely together

• Bacteria in/on our bodies

• Food production (bacteria and bees)​

• ​Tapeworm (parasite)

Symbiosis

​One organisms is a resource for another organsim

• Humans are removed from the food chain, but are predators to many organsims​

Predator / Prey

​

​In human populations:

Multiple Choice

Which type of relationship happens because of limited resources?

• Competition

• Symbiotic relationships

• Predator / Prey

When organisms compete over limited biotic and abiotic resources

• Food / Water / Nutrients

• Shelter / Space / Territory

• Mates ​

Competition

Competition between members of the same species

• Food / Water / Nutrients

• ​Shelter / Space / Territory

• ​Mates

Intraspecies

​

​Competition between members of different species

• Food / water / nutrients

• Shelter / Space / Territory ​

​​Interspecies

​

​Competition between Species

Multiple Choice

Why is competition important?

• Predator and prey relationships help stabilize the food web

• The best competitors are the ones who survive and get to pass on their genes.

• It keeps disease out of ecosystems

• Because energy flows up the food chain and without competition energy wouldn't flow upward

Multiple Choice

Which type of relationship happens to limit populations size?

• Competition

• Symbiotic relationships

• Predator / Prey

Anything that eats another organisms for food. ​

Anything that hunts for it's food. ​

​

​​Predator

​Anything that is eaten by another organism.

Anything that is hunted to be food.

​​Prey

​Predator / Prey

Predator / prey relationships exist to control the population size of other organisms

• Without this relationship populations would grow ​

​

Predator Prey Relationship

​

The number of prey and predators will follow a classic population cycle. There will always be more hares than lynx and the lynx population peak will always come after the population peak for the hares. The population cycle cause and effect so they will be out of phase.

​

​Classic population cycle

Populations increase as food becomes available

Populations decrease as food becomes less available.

​

Population size change from year to year but stay stady over long periods of time. ​

​

Predator Prey Cycle

Multiple Choice

Predator / Prey relationships only keep the prey population in check

• True

• False

Multiple Choice

How is the predator population controlled through a predator prey relationship?

• Predators lose energy as they hunt their prey

• Prey get smarter than the predators so they don't get eaten

• As prey become harder to find, the predator population declines

• Predators find other food sources so they can continue to grow their population

In the next lesson we will look at symbiotic relationships

To do:
Complete the two worksheets