Review and Limiting Factors

Limiting Factors & Carrying Capacity

Food chains are simple linear sequences showing energy transfer.

Food webs show interconnected interactions between organisms.

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Review

Multiple Choice

The way the arrow faces on a food web is important. It shows the transfer of energy from one organism to what consumes it.

• True

• False

Multiple Choice

One organism benefits while harming the other.

• Mutualism

• Commensalism

• Parasitism

Multiple Choice

Both organisms benefit.

• Mutualism

• Commensalism

• Parasitism

Multiple Choice

A rhino has a type of bird that lives near it called an oxpecker. These birds eat ticks off of rhinos, and rhinos get to have free pest control. What type of symbiotic relationship is this?

• Mutualism

• Commensalism

• Parasitism

Mutualism - Both organisms benefit.
Commensalism - One benefits without harming the other.
Parasitism - One benefits while harming the other.

Symbiotic Relationships

Nonliving factors in the environment.
Rocks. Water. Temperature. Soil. Sunlight.

Abiotic

Living factors in the environment.
Deer. Grass. Trees. Fungi. Animals.

Biotic

Biotic vs Abiotic factors

Multiple Select

Which of these are biotic factors?

• Animals

• Trees

• Sunlight

• Temperature

Multiple Select

Which of these are abiotic factors?

• Rocks

• Fungi

• Temperature

• Whelks

Limiting Factors

An environmental condition that restricts the growth of a population in an ecosystem. This can cause the population to decrease, or stop growing.
Example - A limiting factor is food. If there is not enough food available for all the organisms, they will start to die.

Multiple Select

Which of these are limiting factors?

• Food

• Water

• Shelter

• Disease

Things that just kind of happen.
Natural disasters. Diseases. Carrying capacity. Space.

Natural

Some are caused by humans.
Deforestation. Pollution. Overhunting. Introducing invasive species.

Human

Limiting Factors - Continued

Multiple Choice

A disease spreads quickly throughout trees in a forest, causing them to drop all their leaves. Is this a human limiting factor or is this a natural limiting factor?

• Human limiting factor

• Natural limiting factor

Multiple Choice

A dam was built outside of a town, cutting off water and preventing it from flowing down a mountain. The animals no longer have access to water. Is this human or natural?

• Human

• Natural

Multiple Choice

A dam has burst and all of the water floods the surrounding area resulting in a loss of food for other organisms and a bunch of plants. Is this human or natural?

• Natural

• Human

Open Ended

Humans bring over nonnative species, like birds, and will keep them as pets. During a hurricane, the owners are forced to release them as they cannot take them to a shelter and they sustain damage to their house. The birds are now released into the wild, with no natural predators, and compete with other animals for food. They reproduce quickly, have no natural predators, and are considered invasive. Is this natural, human, or both?

The answer would be both

Yes, humans brought the birds here where they are not native.
A storm caused them to be released into the wild, which is natural.
Now, they have no natural predators here to control the population. They reproduce quickly, so they can take over an area faster. They also compete for the resources, and will take food from others.

Multiple Choice

Are limiting factors always negative?

• Yes

• No

It can help with overpopulation. Help maintain stability. And it can help drive natural selection.

​Example - Pythons released into the Everglades are hunted by people to try to stop the spread of the invasive species.

Limiting factors can be positive.

Multiple Choice

Deer hunting helps prevent overpopulation of deer. If the population is not controlled, there will not be enough food for other organisms. Is it positive or negative that the deer population is controlled?

• Positive

• Negative

Multiple Choice

Farmers release nonnative birds into the wild to try to control the population of different insects on their farm. The birds have no natural predators and go after other organisms than just insects. Is this positive or negative?

• Negative

• Positive

Maximum population that an area can sustain.
If the area only has enough food for 750 organisms, what happens if there's 800 organisms?

Carrying Capacity

Multiple Choice

If deer are removed as a food source for wolves, what will happen to the wolves?

• The population will decrease due to loss of food source.

• The population will increase due to them finding another food source.

• The population will decrease because there will be more deer than wolves.

• They'll ask their mom to take them to McDonald's (yippeee)

Poll

Are you confident in your ability to identify limiting factors and biotic/abiotic factors?

• Yes

• Kind of

• Ehhh

• No, to be honest with you, no I am not sorry