Interactions

Interactions

Sunday, March 24, 13

The three major types of interaction among organisms in an ecosystem are

competition

predationsymbiosis

• Resources are the things that organisms obtain from their environment in order to survive.

• They include food, water and shelter.

• Some resources are limited.


Limiting Factors• Anything that restricts or controls the number of

individuals in a population• Includes biotic (living) and abiotic (nonliving)

features of the ecosystem


• All living things compete for– Food and Water– Habitat – Reproduction

• Competition limits population growth• Competition caused by population growth affects

many organisms, including humans

the struggle between organisms that attempt to use the same limited resources

Competition


Predator - PreyPredators are consumers that capture and eat other consumers, called prey

generally have traits that enhance their ability to capture prey, such as fast speed, keen eyesight, and sharp teeth.


Predators


Prey

• Prey have traits that help them avoid being captured, such as the

• ability to escape quickly or to hide in the environment.


PreyAny animal which is hunted and killed by

another animal for food is prey.











Predator






Predator






Predator

Prey






Predator

Prey




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Hares and Lynx PopulationsN

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Hares (x1000) Lynx(x1000)


Which one is the predator and which one is the prey?

lionesszebraSunday, March 24, 13


lionesszebraSunday, March 24, 13


foxhareSunday, March 24, 13


foxhareSunday, March 24, 13


ospreyfishSunday, March 24, 13

Food Chains


Food Chains• The energy flow from one trophic level to

the other is know as a food chain



the other is know as a food chain• A food chain is simple and direct



the other is know as a food chain• A food chain is simple and direct• It involves one organism at each trophic

level




level– Primary Consumers – eat producers




level– Primary Consumers – eat producers– Secondary Consumers – eat the

primary consumers





primary consumers– Tertiary Consumers – eat the

secondary consumers





primary consumers– Tertiary Consumers – eat the

secondary consumers– Decomposers – bacteria and fungi that

break down dead organisms and recycle the material back into the environment


Food Chains - a Reminder


Food Chains - a Reminder• A food chain shows which animals eat

other animals or plants.



other animals or plants.• Plants don’t eat things.



other animals or plants.• Plants don’t eat things.• A food chain starts with what gets

eaten and the arrows point towards what does the eating.



other animals or plants.• Plants don’t eat things.• A food chain starts with what gets

eaten and the arrows point towards what does the eating.

• Food chains only go in one direction.


Food Web

• Notice that the direction the arrow points, the arrow points in the direction of the energy transfer, NOT “what ate what”

Most organisms eat more the JUST one organism

When more organism are involved it is know as a FOOD WEB

Food webs are more complex and involve lots of organisms


Food WebsIn the wild, animals may eat more than one thing, so they belong to more than one food chain.

To get the food they need, small herbivores may eat lots of different plants, and carnivores may eat many different animals.



Breaking the Chain


Breaking the Chain• Organisms living in a habitat depend on each other.


Breaking the Chain• Organisms living in a habitat depend on each other.• If one part of a food chain dies out or is greatly reduced, the

consumers have to find alternative food, move away, or starve.


Breaking the Chain• Organisms living in a habitat depend on each other.• If one part of a food chain dies out or is greatly reduced, the

consumers have to find alternative food, move away, or starve.• This then affects more consumers in the same way.


SymbiosisLiving Together


SymbiosisA close and permanent association between

organisms of different species


Symbiosis

– Mutualism – – a relationship in which both organisms benefit from

each otherExample: Birds eating pest off a rhino’s back

A close and permanent association between organisms of different species


Symbiosis

– Mutualism – – a relationship in which both organisms benefit from

each otherExample: Birds eating pest off a rhino’s back



Mutualism

Cleaner fish

Pollination

Lichens: algae + fungus


MutualismBoth organisms benefit from the relationship

Cleaner fish

Pollination




Otters and Kelp

Cleaner fish

Pollination




The otters help the kelp by eating the sea urchins which endanger it. The kelp provides and anchor for the otters while they sleep.

Otters and Kelp

Cleaner fish

Pollination






Symbiosis

– Commensalism – – a relationship in which one organism benefits and the

other is not affectedExample: Barnacles on a whale



Symbiosis

– Commensalism – – a relationship in which one organism benefits and the

other is not affectedExample: Barnacles on a whale



Barnacles on whalewww.cbu.edu

• A relationship in which one species benefits and the other is neither helped nor harmed

Commensalism

Barnacles and Whales

• Barnacles need a place to anchor. They must wait for food to come their way. Some barnacles hitch a ride on unsuspecting whales who deliver them to a food source. This does not effect the whale in any way.

Cattle with cattle egrets

Cattle stir up insects as they eat grass.Egrets hang around and eat insects.


http://www.cbu.edu/

http://www.cbu.edu/




Symbiosis

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

is harmed• Example: Ticks on a dog



Symbiosis

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

is harmed• Example: Ticks on a dog



Parasitism

Bedbugs are small, nocturnal parasites that come out of hiding at night to feed on unsuspecting humans. They feed exclusively on blood! Their bites often result in an allergic reaction.


Parasitism• One species benefits while the other is harmed



Parasitism• One species benefits while the other is harmed

Mistletoe is an aerial parasite that has no roots of its own and lives off the tree that it attaches itself to. Without that tree it would die. It slowly chokes out the life of the host tree.



Endangered or Extinct?



• The number of people in the world is growing at an alarming rate.




• But this is not true for all animals.




• But this is not true for all animals.• In some cases, there are only a few of one type

of animal left in the wild.





of animal left in the wild.• These animals are endangered.





of animal left in the wild.• These animals are endangered.• If they die out completely, they become

extinct.


Interactions

Documents

prey prey

food chainssunday

food chainsunday

predator prey predators

ability tocapture prey

byanother animal

producers secondary

energy flow