Interaction between organisms

We share our environments with many different species. Some interactions are good while others can be harmful.

Competition

• when two or more individuals or populations try to use the same resource (food, water, shelter, sunlight)

CompetitionCompetition can happen within a population, like these elk who are fighting over the same territory or mate.

Or competition can happen between different populations, like these different species of trees and plants who are competing with each other for sunlight and space.

Predators and Prey – one organism eating the other

• prey – the organism being eaten• predator – the one who eats the prey

When a bird eats a worm, the worm is the prey and the bird is the predator.

Who’s the predator, who’s the prey?Alligator and turtle

Who’s the predator, who’s the prey?

Lion and zebra

Who’s the predator, who’s the prey?Praying mantis and hummingbird

With the predator being so powerful, we start to feel bad for the prey. But nature has given prey a few methods and abilities to help them out.

3 Prey adaptations

Camouflage Defensive Chemicals Warning Coloration

camouflage – blending in with the background

• One way animals avoid being eaten is by being hard to see. Many animals mimic twigs, bark, leaves, stones, or other material in their environment.

A snow fox and a toad are using camouflage to hide.

Can you find me?

A praying mantis

Can you find me?

Two snow grouse

Can you find me?

A flounder

Can you find me?

A leaf mimicking walking stick

Can you find me?

A baby pheasant

Can you find me?

A cicada

Can you find me?

A moth

Can you find me?

A wolf spider

Can you find me?

A weasel

Can you find me?

A wolf

Another prey adaptation is the use of chemicals to defend themselves

• defensive chemicals – inject or spray attackers

Who might do this?

Defensive Chemicals

• The skunk and the bombardier beetle both spray predators with irritating chemicals.

Defensive Chemicals

• Bees, ants, and wasps inject a powerful acid into their attackers.

Defensive Chemicals

• The skin of both the poison arrow frog and a bird called the Hooded Pitohui contain a deadly toxin. Any animal that eats, or tries to eat either of these animals will likely die.

Our last prey adaptation is the use of warning colors

• warning coloration – warn predators that they are dangerous

Predators will avoid any animal that has the colors and patterns they associate with pain, illness, or unpleasant experiences.

The most common warning colors are red, yellow, orange, black, white

Some species have very close interactions with other species

• Symbiosis - close, long-term association between two or more species

Mutualism Commensalism Parasitism

3 main types include:

Mutualism

• both benefit

Mutualism

• Example: good bacteria in your intestines

The bacteria get a meal from you while they help break down food, and you get vitamins that the bacteria produce.

Mutualism

• The aphid and the ant

The ant will protect the

aphid in return for

the honeydew that aphids

produce

Commensalism

• one benefits and other unaffected

Commensalism

• Example: remoras and sharks

Remora fish attach themselvesto sharks to hitch

a ride and eat any scraps left

by the sharks. Sharks are unaffected.

Commensalism

• Clown fish and sea anemone

The clown fish lives among the tentacles of the sea anemone as protection. Seaanemone is unaffected.

Parasitism

• one benefits and the other is harmed

Parasitism

• Parasite – the one that benefits• Host – the one that is harmed

The mosquito is the parasite and the human is the host

Parasitism

• Example: wasp & caterpillar

Wasp lays her eggs on the

caterpillar. When the eggs hatch,

they eat the caterpillar as

food.

Who is the host and who is the parasite?

Parasitism

• In the example of the wasp and the caterpillar, the host dies. Most parasites don’t kill their hosts because parasites depend on their hosts. If a parasite were to kill it’s host, the parasite would have to find another one.

Parasitism

• Roundworms and dogs

Roundworms live inside the dog and feed off its intestinal material, harming the dog.

Who is the host and who is the parasite?

Let’s practice!

Mutualism Commensalism Parasitism

Both benefit One benefitsOther unaffected

One benefitsOther harmed

Mutualism, Commensalism, or Parasitism?

• Barnacles and whales

Barnacles attach themselves to the bodies of whalesand are transported tovast areas where food might be. Whales are unaffected.

Mutualism, Commensalism, or Parasitism?

• Ticks and humans

Ticks suck blood from the human

Mutualism, Commensalism, or Parasitism?

• The Oxpecker and the rhino

The Oxpecker bird eats blood sucking insects off the Rhinos skin.

Mutualism, Commensalism, or Parasitism?

• Cowbirds and dickcissel birdsCowbirds will lay their eggs in the nest of dickcissel birds. When the eggs hatch, the baby cowbirds push out the dickcissel babies and the cowbirds are fed and raised by the dickcissel parents.

Mutualism, Commensalism, or Parasitism?

• The boxer crab and small anemones

The boxer crab will carry small anemones in its claws to scare off predators. In return, the anemones eat any scraps that fall when the crab eats.

Mutualism, Commensalism, or Parasitism?

• Cattle crane and cattle

The cattle crane eats the insects that the cattle stir up as they graze in pastures. Cattle are unaffected.