Relationships between organisms. Connections between organisms All living things on the earth are connected in some way. This unit we will study these.

Relationships between organisms

Connections between organisms• All living things on the earth

are connected in some way.• This unit we will study these

relationships:– Producer/consumer/decomposer– Predator/Prey– Competition– Symbiosis

Producer/consumer/decomposer

• We’ve already learned that a producer is able to use the sun’s energy to make food.

• We’ve also learned that a consumer has to get food by eating producers (herbivore) or other consumers (carnivore) or both, (omnivore).

Producer/consumer/decomposer

• Producers (autotrophs) capture the energy that all other organisms rely on to survive.

• Without producers, the sun’s energy couldn’t be used by living things.

Producer/consumer/decomposer

• A decomposer is an organism that breaks down waste and dead organisms.

• Decomposers help to recycle nutrients.

• Without decomposers, dead things would pile up, and nutrients would run out.

Producer/consumer/decomposer

• Are each of these organisms a producer, consumer, or decomposer?

Consumers - Predator/Prey

• An organism that kills and eats another organism for food is called a predator.

• An organism that gets killed and eaten by a predator is called the prey.

Predator/Prey

• Predator populations rise and fall in relation to the prey they eat.– (If there is a decrease in

the amount of prey, there will soon be a decrease in the amount of predators).

– (If there is an increase in the amount of prey, there will soon be an increase in the amount of predators).

Predator/Prey

• Example: Voles vs. Birds of Prey in Cache Valley – Christmas Bird Count

2011– Wet Spring led to record

low number of voles– Fewer birds of prey

reported that Christmas.

Competition

• Competition occurs when 2 or more organisms are both trying to use the same limited resource.

Competition

• Competition could occur between producers or consumers

• Competition might occur between organisms of the same species, or different species.

Competition

• Competition might occur because of limited:– Food– Space– Sunlight– Mates– Or any other limited

resource

Carrying capacity

• The maximum amount of individuals of a certain species that an environment can support is called the carrying capacity.

Carrying capacity

• Example: Eurasian Collared Doves in Cache Valley

Limiting factor

• The resource that runs out when a population reaches its carrying capacity is called the limiting factor.

• Limiting factors lead to competition between organisms.

Symbiosis• Symbiosis is when two

different species of organisms live closely together for an extended period of time.– “Sym” = same– “bio” = life

• There are 3 types of symbiosis:– Mutualism– Commensalism– Parasitism

Symbiosis - Mutualism

• Mutualism is when the 2 organisms both benefit from the relationship. (They help each other.)

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Symbiosis – Mutualism - Examples

Symbiosis - Commensalism

• Commensalism is when one of the organisms benefits from the relationship, and the other is not helped or harmed by it.

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Symbiosis – Commensalism - Examples

Symbiosis - Parasitism

• Parasitism is when one organism benefits from the relationship, and the other organism is harmed.

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Symbiosis – Parasitism - examples

Symbiosis - ?

• Why don’t we have a word for a relationship where both organisms are harmed by the relationship?

Symbiosis and you

• What is one example of mutualism that a person might be involved in?

• What is one example of commensalism that a person might be involved in?

• What is one example of parasitism that a person might be involved in?

Symbiosis and you

• Think about your friends.– What would a mutualist

friend be like?– What would a

commensalist friend be like?

– What would a parasitic friend be like?

– What type of friend are you?