Interactions and Relationships in an Ecosystem

How Energy Flows

Nutritional Relationships

Involve the transfer of nutrients from one organism to another within an ecosystem

AUTOTROPHS

Organisms that can make organic molecules (food) from inorganic molecules (using sun—usually)

Aka producers Can be photosynthetic (sun) or

chemosynthetic

(chemicals in ocean

vents)

HETEROTROPHS

Cannot make organic molecules (food)

Aka consumers Five types

Herbivores Carnivores Omnivores Scavengers Decomposers

HETEROTROPHS cont.

Types of heterotrophs Herbivores

Only eat producers Aka primary (1st level) consumer

Carnivores Only eat other animals Aka secondary or tertiary (2nd or 3rd

level) consumer

HETEROTROPHS cont.

Types of heterotrophs Omnivores

Eat anything Can be 1st, 2nd or 3rd level consumer

Scavengers Eat only other animals after they are

already killed Usually 2nd or 3rd level consumer

HETEROTROPHS cont.

Decomposers Live on dead matter Aka saprophytes Include plants, fungi and bacteria

Stop and Jot

STOP-AND JOT: How do you get your energy? Finish the sentence below:

I am a ____________________________________________________________

Keystone Quiz The red wolf is an endangered species in the

southeastern part of the United States. These animals are carnivores and eat deer, rodents, and small mammals. Which change in the environment would most likely threaten the population of red wolves?

A.Release of a large number of deer into the wolf range

B. Extensive loss of habitat due to deforestation

C. An abnormally wet summer

D.An abnormally warm fall

Food ChainsFood Chain: shows the pathway of energy

from one organism to the next in a direct line

Always starts with producers

Autotroph herbivore carnivores

Algae krill cod leopard seal

Arrow goes into the mouth! (you put your food into your mouth)

STOP-AND JOT: write underneath each organism what it eats. Then write if it is a producer, herbivore, omnivore or carnivore

1st trophic level

2nd trophic level

3rd trophic level

4th trophic level

5th trophic level

Stop and JotSTOP-AND-JOT: write underneath each organism what trophic level (number) it “sits in”. Then write what type/level of producer or consumer it is. (primary, secondary, tertiary, quaternary and

producer or consumer)

Food WebShows the

interactions and interconnections among the different food chains of a community

Shows more than one energy

pathway

Stop and Jot

What are some differences between a food chain and a food web?

Stop and Jot:Here is another example of a food web. Label each organism using the following abbreviations: Producer (P); Herbivore (H); Omnivore (O); Carnivore (C)

Keystone Quiz

Food webs and food chains are two different ways that ecologists illustrate the interrelatedness of organisms in an ecosystem. What is the relationship between a food web and food chain?

A. Food chains are only used to illustrate organisms that consume only one kind of organism rather than multiple kinds of organisms, as illustrated in a food web.

B. Food webs illustrate all the organisms in an ecosystem dependent on one food chain.

C. Food chains illustrate only one tropic level of a food web.

D. Food webs illustrate multiple interrelated food chains.

Energy PyramidsAt each step of the food web/chain, energy

is transferred to the next higher levelSun plant rabbit snake hawkThis energy transfer is NOT EFFICIENTOnly 10%10% of the energy passed to the next

generation is usable; most energy is lost maintaining homeostasis and as heat

The amount of usable energy decreases at each higher feeding level

Keystone Review Quiz1. All living organisms use energy. They also grow and

reproduce. What is another characteristic of all living organisms?

A. All living organisms consist of many cells with specialized organelles

B. All living organisms are complsed of one or more cells.

C. All living organisms must consume food in order to acquire nutrition.

D. All living organisms can produce glucose through photosynthesis

Keystone Review Quiz2. A(n)________is a tentative, testable statement about the natural world that is capable of being supported or refuted by scientific evidence, whereas a(n) _________ is a well-established and highly-reliable explanation of a natural phenomenon.

A.theory; hypothesis

B.Opinion; theory

C.Hypothesis; theory

D.Hypothesis; opinion