Big Idea 17: InterdependenceDescription   A. Plants and animals, including humans, interact with and depend upon each other and their environment to satisfy their basic needs. B. Both human activities and natural events can have major impacts on the environment. C. Energy flows from the sun through producers to consumers.

Benchmark Number& Descriptor

SC.7.L.17.1 Explain and illustrate the roles of and relationships among

producers, consumers, and decomposers in the process of energy transfer in a food web.

SC.7.L.17.2 Compare and contrast the relationships among organisms

such as mutualism, predation, parasitism, competition, and commensalism.

SC.7.L.17.3 Describe and investigate various limiting factors in the

local ecosystem and their impact on native populations, including food, shelter, water, space, disease, parasitism, predation, and nesting sites.

Ecosystems include… Organisms that live in a particular area

physical surroundings

Organisms interacting with each other

by sharing and competing for resources

Organisms interacting with their physical environment

Bottom Line: Ecosystems can be found wherever organisms are

living and interacting!

HABITAT & NICHE ENVIRONMENTAL FACTORS

ECOLOGICAL RELATIONSHIPS

Habitat – An organism’s habitat is where it lives in an ecosystem.

Niche – a certain role that each population has in its environment (ex. Both eagles and owls feed on mice, but owls hunt at night while eagles hunt during the day.)

In a healthy ecosystem, populations are interdependent – they depend on each other for survival!

The environment determines the type

of ecosystem that will develop in an area.

Factors include:

Soil conditions

Temperature

Rainfall

Plant Life

Amount of Food

1. A single organism in an environment is called an _______.

2. In a healthy ecosystem, each population contributes to the ______ of the other populations.

3. The amount of food is a ________ that affects population density.

4. A ______ is a place where a population lives in an ecosystem.

5. A population has a role or _______ in its environment.

6. The sizes of animal populations are determined by the kinds and numbers of __________ in an ecosystem.

Word Bank:

niche plants

individual habitat

limiting factor survival

KNOWLEDGE CHECK

1. A single organism in an environment is called an individual.

2. In a healthy ecosystem, each population contributes to the survival of the other populations.

3. The amount of food is a limiting factor that affects population density.

4. A habitat is a place where a population lives in an ecosystem.

5. A population has a role or niche in its environment.

6. The sizes of animal populations are determined by the kinds and numbers of plants in an ecosystem.

KNOWLEDGE CHECK

How Energy Is Transferred in an Ecosystem

The sun provides the energy for almost every ecosystem on Earth. Producers use the sunlight to make food they need from carbon dioxide and water (ex. plants).

Consumers – all the animals in a community (ex. all the animals that are eating)

Food Chains Food chains show how consumers,

producers, and decomposers are

related for survival.

Begins with producers (usually

plants)

Next level contains herbivores –

animals that eat only plants.

They are eaten by the next level of

animals on the food chain – the

carnivores (meat eaters).

The chain continues with more

levels of carnivores that eat one

another.

The chain ends with decomposers

such as bacteria which breaks down

the tissues of dead organisms.

Whatever is left over returns to the

soil and helps start the cycle over

again by giving nutrients to the

producers!

EXAMPLES of PRODUCERS AND CONSUMERS

Both land and marine

EXAMPLES of FOOD CHAIN RELATIONSHIPS

GRASSES(producers)

Zebras and GazellesPrimary Consumers Herbivores

Insects, Birds, Hyenas, WormsSecondary and Tertiary consumersCarnivores, Omnivores

LionsPredator

Energy from the grass is both used and stored by the animals who eat the grass

directly and by those who eat those animals.

KNOWLEDGE CHECK1. Where are ecosystems found?

2. What are the three links in the food chain?

3. Give an example of each link in the food chain.

KNOWLEDGE CHECK1. Where are ecosystems found?

Ecosystems can be found wherever organisms are living and interacting!

2. What are the three links in the food chain?Producer, Consumer, Decomposer

3. Give an example of each link in the food chain. Producer = Plants

Consumer = BearDecomposer = Bacterial

ECOLOGICAL RELATIONSHIPS

COMPETITION Resources in ecosystems

may be limiting; therefore, competition for these resources may occur.

Resources under competition may include food, water, sunlight, or shelter

The more needs that are in common, the more intense the competition.

If an organism competes successfully for resources, it is more likely to survive and reproduce!

This is why there are PREDATORS and PREY!

ECOLOGICAL RELATIONSHIPS

Symbiosis: A close relationship between organisms of different species

4 types of symbiosis:

Commensalism

Mutualism

Parasitism

Mimicry

ECOLOGICAL RELATIONSHIPS

Commensalism- A relationship in which one organism benefits and the other is not affected

Mutualism – A relationship in which both organisms benefit from each other

Parasitism – A relationship in which one organism benefits and the other is harmed

Mimicry – When species mimic colors, patterns, or behavior of another species in order to get closer to unsuspecting prey or to gain protection by imitating a predator

Imperial shrimp hitching a ride on a sea-cucumber

Clownfish in host sea anemone

Parasitic Isopod on fish

Two of these are Bumblebees(with stingers)

and two are Robber Flies (which also make a sound

similar to a bee).

KNOWLEDGE CHECKLiving on the Serengeti Plain are

herds of lions, zebras, hyenas, birds, ticks, and fleas. Using this information, list the ecological relationships in terms of competition and symbiosis.

KNOWLEDGE CHECK Living on the Serengeti Plain are herds of lions,

zebras, hyenas, birds, ticks, and fleas. Using this information, list the ecological relationships in terms of competition and symbiosis.

SYMBIOSIS COMPETITION

Mutualism: Zebra and Bird Zebra and Hyena

Commensalism: Lion and Hyena (Both eat grass).

Parasitism: Flea and Lion

LIMITING FACTORS Limiting factors are

things that prevent a population from growing any larger.

If any of the limiting factors change, animal and plant populations change, too.

Limiting factors include:

Water

Food

Shelter

Space

Predation

Disease

SHELTER/SPACE

Limiting FactorsFOOD/WATER If there is limited food

for a population, the species will not survive.

Lack of food or water can create competition among populations and species.

Without proper nutrition, species cannot thrive and survive.

SHELTER: is a prime factor. Without proper shelter, predators can diminish a population quickly.

SPACE: Humans can impact animal and plant populations. When humans develop land for houses and buildings, they cut down trees and change animal and plant habitats.

Limiting Factors Limiting factors are very closely tied to carrying capacity.

Many kinds of animals can increase in numbers very quickly and may temporarily exceed the carrying capacity of their habitat.

This results in stress, starvation, disease, predation, and parasites, poor reproductive success and damage to the habitat.

For example, multiplying muskrats can very quickly eat all the vegetation in a marsh. With the vegetation gone, food becomes the limiting factor, and the muskrats may starve or move to another area. The marsh now has a reduced carrying capacity for muskrats until the vegetation grows back again.

http://homestudy.ihea.com/wildlife/09limits.htm

KNOWLEDGE CHECKLiving on the Serengeti Plain are

herds of lions, zebras, hyenas, birds, ticks, and fleas. Using this information, what is/are the limiting factor(s) of this ecosystem?

KNOWLEDGE CHECKLiving on the Serengeti Plain are herds

of lions, zebras, hyenas, birds, ticks, and fleas. Using this information, what is/are the limiting factor(s) of this ecosystem?

Grass and water. Without these, the bottom of the food pyramid would disappear, creating a chain reaction to the top.