HMH Unit 3.3 Day Three

HMH Unit 3.3 Day Three

Pgs 205-208

​What Group Are You In?

• ​The living things in an ecosystem interact with one another. Living things live with other organisms and nonliving things in the ecosystem.

Population

• ​A group of organisms of the same kind in an ecosystem, like this herd of elephants, is called a population.  The members of a population interact with one another.  They have very similar needs. They eat the same kind of food and need the same kind of shelter.  They all need water and space to grow and find food.  The members of a population interact as they meet their needs.

​Community

• ​The different populations that share an ecosystem make up a community.  A community consists of all the populations that live and can interact in an area.  The living things in a community might not have all the same needs. Even if they have different needs, the population in a community interact.

​Do the Math

• ​You have been asked to help the owners of a nature preserve decide if they have enough land to support a community of zebra and antelope. In order for the animals to get what they need, 8,000  square meters of land are needed for each zebra, and 2,000 square meters of land is needed for each antelope. The preserve is 1.70 square kilometers in size. The preserve owners would like to have 200 zebra and 60 antelope in the preserve.

• ​Will the preserve have enough space to accommodate all of these animals? If not, how many more acres of land will they need?

​Do the Math

• ​There will not be enough land for these animals, because 200 zebra and 60 antelope will require 1.72 square kilometers of land. The preserve will need to be .02 square kilometers larger for all of the animals to meet their needs.

Multiple Select

What will happen in an ecosystem if there are not enough resources to support all of the populations of living things found there?  Choose all that apply

•  Some living things might move to a new ecosystem

• Many more living things will move into the ecosystem

• Some living things might die

• More resources will be produced to meet the demands of the living things

• Some living things will struggle to get what they need.

​What Would Happen?

​Resources in any ecosystem are limited.  There is only so much space available in an ecosystem.  There are limited amounts of water and of food. Since space, water and food are limited, they may be limiting factors.

Limiting factors limit how many living things of a particular population an ecosystem can support.

​Limited Supplies

​The living things in an ecosystem often have to compete with one another to get what they need to survive.  Individuals and populations that compete successfully will get the resources they need. They will survive.  Individuals and populations that do not compete successfully cannot get what they need.  They will no survive unless they move.  

Food is a resource that all animals need to survive. Look at the pictures on the next slide to see how some animals get the food they need.

Multiple Choice

Grizzly bears eat many types of food. It isn’t uncommon to find them catching and eating salmon in the rivers.  Which is the one eating the food?

• Grizzly Bear

• Salmon

Multiple Choice

Grizzly bears eat many types of food. It isn’t uncommon to find them catching and eating salmon in the rivers.  Which is the one is being eaten?

• Grizzly Bear

• Salmon

Multiple Choice

Some insects eat other animals. This dragonfly is getting food by catching and eating a wasp.  Which one is eating the food?

• Dragonfly

• Wasp

Multiple Choice

Some insects eat other animals. This dragonfly is getting food by catching and eating a wasp.  Which one is being eaten?

• Dragonfly

• Wasp

Multiple Choice

Snakes need to hunt for their food. This snake gets the food it needs by catching and eating mice. Which one eating the food?

• Snake

• Mouse

Multiple Choice

Snakes need to hunt for their food. This snake gets the food it needs by catching and eating mice. Which one is being eaten?

• Snake

• Mouse

​Eat or be Eaten

• ​You’ve read that the living things in an ecosystem interact.  You’ve seen that competition for resources is one way populations interact.  The pictures on the previous slides showed another kind of interaction-the interactions between predators and prey.

​Eat or be Eaten

• ​Predators are animals that hunt, catch, and eat other animals to get food they need.  Prey are the animals they catch and eat.  In an ecosystem, predator and prey populations interact.

• ​Which are the predators and which are the prey in these pictures?

Multiple Select

Which organisms are predators? Choose all that apply

• A wolf that eats a moose

• A rabbit that eats grass

• A mouse that eats seeds

• A bird that eats worms