Interactions of Life

Interaction There are three main types of interaction between organisms: Competition Predation Symbiosis

Competition Different species can share the same habitat. Different species can share the same food requirement. If two species share the same niche, the result is competition and one will usually squeeze the other out. Gause’s principle.

Competition Who will be victorious?

Predation An interaction between species in which one kills and eats the other is called predation Predators have adaptations to help them catch prey Prey have adaptations to help them avoid being caught

Predation: Predator-Prey Relationships Exploitative Competition Predator: animals that feed on other animals (can also be applied to herbivores feeding on plants) How is this Harmful to prey? How does this Benefit prey species? What is the Potential Benefit to Biotic Community?

Predation

Predation: Linkage of predator and prey population sizes Decreased predator --> increased prey Increased predator --> decreased prey Decreased predator --> increased prey Increased predator --> decreased prey

Interactions of Predator and Prey

Hydra Preys on Daphnia

Symbiosis A close relationship between two species that benefits at least one of them. 3 types of symbiotic relationships – Mutualism – Commensalism – Parasitism

Mutualism: Symbiotic relationship where both species benefit

Mutualism Butterflyweed provides food for butterflies like pipevine swallowtails. Butterflies like pipevine swallowtails pollinate butterflyweed. Mutualism: a relationship between two species where both benefit.

Example of Mutualism Oxpeckers (aka tickbirds):

Example of Mutualism Acacias and Ants

Example of Mutualism Ants and Aphids coolandunusualinsects/f/an tsandaphids.htm

Mutualism The acacia provides benefits to ants –shelter (hollow thorns) –nectar nectar (secreted near base of leaves) The ant –attacks and removes herbivorous insects –removes vines that might overgrow the acacia –kills the growing shoots of nearby plants that might become competitors. –clears away leaf litter from near the plant protecting the tree from fire damage as well A mutualism between certain ants and a small tree, the acacia.

Examples of Mutualism Clownfish and Sea Anemone: Termites and Protozoans:

Mutualism Lichens grow in the leftover spots of the natural world that are too harsh or limited for most other organisms. They are pioneers on bare rock, desert sand, cleared soil, dead wood, animal bones, rusty metal, and living bark. "Lichens are fungi that have discovered agriculture"-- lichenologist Trevor Goward.

Mutualism Lichens are composite, symbiotic organisms made up from members of as many as three kingdoms. The dominant partner is a fungus. Fungi are incapable of making their own food. They usually provide for themselves as parasites or decomposers. The lichen fungi (kingdom Fungi) cultivate partners that manufacture food by photosynthesis. Sometimes the partners are algae (kingdom Protista), other times cyanobacteria (kingdom Monera), formerly called blue-green algae. Some enterprising fungi exploit both at once.

Commensalism Symbiotic relationship where one species benefits and the other is neither helped nor harmed

Commensalism Commensalism is a relationship between two species in which one species obtains benefit from the other, without harming or benefiting it. The Antarctic scallop may have a bush sponge attached near the shell's peripheral margin. The sponge is seeking the water flow over the scallop shell in order to facilitate its own filter feeding.

Example of Commensalism Epiphytes:

Example of Commensalism Remora

Example of Commensalism Barnacles on Whale

Symbiotic Interactions Symbiosis: close relationship between two species Parasitism: symbiotic relationship where one species benefits and the other is harmed

Parasitism The tomato hornworm feeds on the foliage of the tomato plant The braconid wasp lays eggs in a tomato hornworm. The eggs hatch into a wasp larva that feeds on the internal organs of the hornworm. Pupa of the wasp form on the skin of the hornworm Tomato hornworm with Braconid wasp parasite s (pupae). Tomato hornworm Braconid wasps lay eggs under the skin of the hornworm

Parasitism Mistletoe has solved the problem of water by growing as a parasite on this tree. (photo R.K. McConeghy) Mistletoe is a parasitic plant that grows on trees, particularly hardwood trees like oak and apple. As mistletoe grows on a tree, it sends out its roots right into the tree's bark and takes nutrients from the tree. Sometimes, mistletoe can harm a tree and cause deformities in a tree's branches, but usually it doesn't kill its host. If the host dies, the mistletoe dies. This red mistletoe is growing from the trunk of a tree. Mistletoe is a parasitic plant that grows on trees.

Examples of Parasitism Sea Lampreys:

Examples of Parasitism Poison Ivy:

Human Parasites