TA symbiosis.notebook
1 April 12, 2016
Apr 1111:25
Symbiosis.
Apr 1113:26
Interactions Within Communities
1. What are the three types of symbiotic relationships?
2. Describe the three symbiotic relationships.
3. Describe an example of a symbiotic relationship involving humans.
4. Describe a symbiotic relationship involving plants and insects.
5 Define mutualism and commensalism.
6. Give examples of mutualism.
7 Explain why most parasites do not kill their host. Why is it in their own best interest to keep their host alive?
Homework. For next Tuesday.
Apr 1112:12
Symbiosis We are learning:
Different kinds of organisms can live together to promote the survival of one or both creatures.
To define symbiosis.
To compare and contrast mutualism, commensalism, and parasitism.
Symbiosis is a close relationship between 2 organisms in which at least one organism benefits. For the other species, the relationship may be positive, negative or neutral.
There are 3 types of symbiosis. Commensalism, (neutral) Parasitism (negative) and Mutualism (positive)
Apr 1111:31
Symbiosis in flowering plants and pollinators.
Apr 1209:39
Symbiosis in Mycorrhiza
A mycorrhiza can be defined as a mutualistic association between a fungus and a root or other underground organ of a plant.
Typically, the fungus penetrates the root tissues and obtains at least part of its carbon requirements from the plant, while the plant benefits by enhanced uptake of mineral nutrients via the fungal hyphae that grow through the soil.
Mycorrhizal associations are found in more than 70% of vascular plants (angiosperms and gymnosperms) as well as many ferns.
Mycorrhizal associations developed early in the history of land plants,as shown by fossils and have been maintained to this day.
The relatively few nonmycorrhizal plants tend to grow in open habitats, where competition for soil nutrients may not be a major problem, but mycorrhizas are normal in closed plant communities.
Apr 1112:56
Commensalism bringing neither benefit nor harm.
Do interactions between species always result in a negative or positive effect?
A commensal shrimp sits on another sea organism, a sea slug. As a commensal shrimp, it neither brings a benefit nor has a negative effect on its host.
Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. One species typically uses the other for a purpose other than food. For example, mites attach themselves to larger flying insects to get a “free ride.” Hermit crabs use the shells of dead snails for homes.
TA symbiosis.notebook
2 April 12, 2016
Apr 1113:05
Mutualism both species benefit from the relationship.
Mutualism
Mutualism is a symbiotic relationship in which both species benefit. An example of mutualism involves goby fish and shrimp (see picture above). The nearly blind shrimp and the fish spend most of their time together.
The shrimp maintains a burrow in the sand in which both the fish and shrimp live. When a predator comes near, the fish touches the shrimp with its tail as a warning.
Then, both fish and shrimp retreat to the burrow until the predator is gone. From their relationship, the shrimp gets a warning of approaching danger. The fish gets a safe retreat and a place to lay its eggs.
A mycorrhiza can be defined as a mutualistic association between a fungus and a root or other underground organ of a plant. Typically, the fungus penetrates the root tissues and obtains at least part of its carbon requirements from the plant, while the plant benefits by enhanced uptake of mineral nutrients via the fungal hyphae that grow through the soil. But there are exceptions, explained later.
Mycorrhizal associations are found in more than 70% of vascular plants (angiosperms and gymnosperms) as well as many pteridophytes (ferns and their allies) and some bryophytes (especially liverworts). Indeed, structures resembling some of today's mycorrhizas have been found in plant fossils from the Devonian period. So, mycorrhizal associations developed early in the history of land plants, and have been maintained to this day. The relatively few nonmycorrhizal plants tend to grow in open habitats, where competition for soil nutrients may not be a major problem, but mycorrhizas are the norm in closed plant communities.
Apr 1113:15
Parasitism
Parasitism is a symbiotic relationship in which one species (the parasite ) benefits while the other species (the host ) is harmed. Many species of animals are parasites, at least during some stage of their life. Most species are also hosts to one or more parasites.
Some parasites live on the surface of their host. Others live inside their host. They may enter the host through a break in the skin or in food or water. For example, roundworms are parasites of mammals, including humans, cats, and dogs (see picture above). The worms produce huge numbers of eggs, which are passed in the host’s feces to the environment. Other individuals may be infected by swallowing the eggs in contaminated food or water.
Parasitism one organism benefits positively, while the other organism is harmed
Some parasites kill their host, but most do not. It’s easy to see why. If a parasite kills its host, the parasite is also likely to die. Instead, parasites usually cause relatively minor damage to their host.
Apr 1209:57
Symbiosis in corals.
Coral lives a symbiotic life. Inside the sac of each coral polyp lives a onecelled algae called zooxanthellae (zoozanthely). The algae gives off oxygen and other nutrients that the coral polyp needs to live and in return the polyp gives the algae carbon dioxide and other substances the algae needs. That is why coral reefs grow so near the surface of the water where it is the sunniestthe algae need sunshine for photosynthesis.
Apr 1113:24
Summary
· Symbiosis is a close relationship between two species in which at least one species benefits.
· Mutualism is a symbiotic relationship in which both species benefit.
· Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected.
· Parasitism is a symbiotic relationship in which one species (the parasite) benefit while the other species (the host) is harmed.
Coral seas. The blue planet. Attenbourgh.
