Parasites and Mutualists

Parasites and Mutualists:

In most feeding relationships the predator kills and eats it's prey. Parasitism is a feeding relationship in which two organisms live together in which one is feeding off the other. The organisms that feeds is called a parasite and the organisms it feeds on is the host.

Some parasites live outside a host's body e.g. Headlice. Others live inside. The tapeworm live in the intestines of vertebrates. Tapeworms eggs live the host's body through it's faeces. Their eggs are then swallowed by other animals and tapeworms grow inside them.

Parasites harm their hosts. Tapeworms take nutrients from the host's gut. This can cause the host to lose weight.

European mistletoe is a parasite plant. It's leaves photosynthesis but its roots grow into the veins of a host tree and absorb its mineral salts.

Mutualism is when two organisms live together but both organisms benefit. One such pair are oxpeckers and large herbivores in Africa. Oxpeckers eat parasitic insects that live on the herbivore . The herbivore carrier around the oxpecker on its head.

Another such example is when cleaner fish eat parasites from the skin of larger fish while the larger fish carry them around.

Some organisms live in mutualistic relationships inside other organisms. Nitrogen-fixing bacteria is a bacteria that can turn nitrogen in the air into nitrogen compounds. Some live in the roots of legumes (plants that produce pods). The bacteria gains chemical substances from the plant which they use as food. The plant gains nitrogen compounds so it can grow well.

Chemosynthetic bacteria are producers who get their energy from chemical substances rather then light. Some live inside tubeworms. Tubeworms get chemicals the bacteria needs and tubeworms feed on substances made by bacteria.


Key Words:

Prey 
Predator
Parasitism
Parasite
Host
Mutualism
Cleaner fish
Nitrogen-fixing bacteria
Legumes
Chemosynthetic bacteria


Questions:

1. How do headlice benefit from parasitism
2. How can a tapeworm kill its host?
3. How do both the oxpecker and herbivore benefit from mutualistic relationship?
4. What is the difference between parasitic and mutualistic relationships?


What you should Know:

How the survival of some organisms may depend on the presence of another species:
a. Parasitism including:
i. fleas
ii. head lice
iii. tapeworms
iv. mistletoe
b. Mutualism including:
i. oxpeckers
ii. cleaner fish
iii. nitrogen-fixing bacteria in legumes
iv. Chemosynthtic bacteria in tube worms in deep-sea vents.