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Species Interactions

5 Major Types of Species Interactions Symbioses are interactions between species. Predation Parasitism Competition Mutualism Commensalism

Predation

Species Interactions Predation One individual captures, kills, and consumes, another individual (predator-prey). Evolution (natural selection) favors adaptations Helps to regulate populations size

Predation Predators survival depend on their ability to catch prey. The prey’s survival depends on its ability to avoid being captured. What types of defense could prey have to avoid being captured? Possibilities Speed, mimicry, camouflage, bright colors to warn of toxicity (poisonous)

Camouflage

Leaf Mimic Insect

Camfouflage Brookesia superciliaris chameleon in leaf litter.

Mimicry Poison arrow dart frog (below) Mantella Frog (above) resembles the poisonous poison arrow dart frog.

Mimicry

The owl butterfly mimics the eye of a potential predator to scare off an attacking individual.

Plant-herbivore interactions Another Form of Defense Animals that eat plants are considered to be in predator - prey relationships. Some plants synthesize chemicals known as secondary compounds that are poisonous or irritating to the herbivore consuming them. Example: Poison ivy

Parasitism Parisitism is an interaction where one organism benefits and the other organism is harmed. How is this different than predation? Vocabulary Parasite- The individual that benefits. Host – The individual that is harmed.

Parasitism Vocab Cont… Parasites are divided into two categories based on their interaction with the host. Ectoparasites – External parasites that do not enter the hosts body. Endoparasites – Parasites that are internal and live inside the hosts body.

Ectoparasite or Endoparasite? Ascaris Lives in the intestine. May be fatal if the larvae infiltrate vital parts of the body.

Ascaris life cycle Ball of Ascaris passed from a host’s intestine.

Ectoparasite or Endoparasite?

Fleas

Ectoparasite or Endoparasite? Ticks

Ectoparasite or Endoparasite? Leeches

Ectoparasite or Endoparasite? Found in approximately 25% of the world’s population. Larva enter through the skin, find their way into bloodstream and migrate to the lungs and are eventually swallowed, living in the intestines up to 10 years. Cause abdominal pain and iron deficiency. Hookworm

Ectoparasite or Endoparasite? Pinworm –Extremely contagious. Affects 80% of children between ages of 2 and 10. Female lays eggs outside the anus during the night and returns to the colon. Person scratches and then may reingest the eggs or pass them. Female may lay eggs in one night.

Host Defense Against Parasites Examples: Skin, openings such as eyes, mouth, and nose are defended with tears saliva and mucus. Parasites passing through these openings may be attacked by the immune system.

Specialized Parasites Parasites efficiently exploit their hosts without killing the host (in most circumstances) Examples: The tapeworm are so specialized that they have no digestive system. They live in the small intestine and absorb nutrients through the skin.

Competition Competition results from the use of the same limited resources by 2 or more species (niche overlap). The more resources the 2 species share the more intense the competition. Competitive exclusion is when one species is eliminated as a result of competing for the same limited resource. Character displacement according to evolutionists is when competitors evolve niche differences or anatomical differences that lessen the intensity of competition. The difference is often greatest where the competitors overlap.

Competition Resource partitioning is when the similar species coexist but each species only uses part of the available resources.

Mutualism Mutualism is a cooperative relationship in which both species derive some benefit. Some relationships are so close that the individuals may not survive without the other. One of the most important mutualistic relationships is pollination. How does pollination work? Animals that carry pollen are called pollinators.  Examples birds, bees, butterflies, beetles, moths etc…

Pollination is one of the most important mutualistic relationships on earth. Moth collecting nectar.

Many types of organisms are pollinators.

Termites are unable to digest wood so they ingest a bacteria that digests it for them. Termites Bacteria

Lichens Lichens are symbiotic associations of a fungus with a photosynthetic partner (photobiont) that can produce food for the lichen from sunlight. The photobiont is usually either green alga or cyanobacterium.

remarkable 3-way mutualism appears to have evolved between an ant, a butterfly caterpillar, and an acacia in the American southwest. The caterpillars have nectar organs which the ants drink from, and the acacia tolerates the feeding caterpillars. The ants appear to provide some protection for both plant and caterpillar. Research of Diane Wagner, American Museum of Natural History Southwestern Research Station

Egyptian Plover Bird

The Egyptian Plover Bird picks leeches out of the teeth of the crocodile. How does this benefit the crocodile? How does this benefit the Plover Bird

Commensalism Commensalism is a relationship in which one individual benefits and the other is unaffected.

Cape Buffalo and Cattle Egret The egrets feed off of lizards and insects forced out of hiding while the buffalo moves through the grass. Cape buffalo in Tanzania

Barnacles on a Whale

Question? Explain how predators differ from parasites.

Question Some harmless flies resemble bees and wasps. What is this mechanism called? Why is it important?

Question If cattle egrets removed ticks from Cape buffalos would their relationship still be commensalism?

Question? Explain how two similar species of birds are able to inhabit the same area and even nest in the same tree without occupying the same niche.

Question? What is the advantage of character displacement?