Organisms and their Relationships

Organisms and Their Relationships Ecology The study of relationships between living organisms and the interaction they have with their environments Ecologists observe, experiment, and model using a variety of tools and methods.

A thin layer around Earth Organisms and Their Relationships Biosphere A thin layer around Earth Extends several kilometers above the Earth’s surface Extends several kilometers below the ocean’s surface The biosphere is the broadest level of ecological study, the global sum of all ecosystems

Organisms and Their Relationships The Biosphere

Living factors in an organism’s environment Organisms and Their Relationships Biotic Factors Living factors in an organism’s environment

Nonliving factors in an organism’s environment Organisms and Their Relationships Abiotic Factors Nonliving factors in an organism’s environment Weather, rocks, sunlight, etc. Organisms adapt to survive in the abiotic factors present in their natural environment.

Levels of Organization Organisms and Their Relationships Levels of Organization Levels increase in complexity as the numbers and interactions between organisms increase. biosphere biome ecosystem community population organism

The lowest level of organization is the individual organism itself. Organisms and Their Relationships The lowest level of organization is the individual organism itself. Organisms of a single species that share the same geographic location at the same time make up a population. A community is a group of interacting populations that occupy the same geographic area at the same time.

Organisms and Their Relationships An ecosystem is a biological community and all of the abiotic factors that affect it. A biome is a large group of ecosystems that share the same climate and have similar types of communities.

Levels of Organization Organisms and Their Relationships Levels of Organization Organism- any single living species Populations – groups of the same species that live in the same area Communities – different populations living together in a defined area Ecosystem – all living (Biotic) and non-living (Abiotic) components Biome – group of ecosystems in a similar climate Biosphere – collection of all biomes

Ecosystem Interactions A habitat is an area where an organism lives. Organisms and Their Relationships Ecosystem Interactions A habitat is an area where an organism lives. Habitat destruction is the main reason that organisms are endangered or extinct (ADD TO NOTES) A niche is the role or position that an organism has in its environment.

Organisms and Their Relationships

Community Interactions Organisms and Their Relationships Community Interactions Competition Occurs when more than one organism uses a resource at the same time Predation Many species get their food by eating other organisms.

Community Interactions Symbiotic Relationships Organisms and Their Relationships Community Interactions Symbiotic Relationships The close relationship that exists when two or more species live together Mutualism Both organisms benefit Possibly the most famous of mutualistic relationships is the lichen. Actually there are hundred of "species" of lichens. A lichen looks like a plant, but is actually a complicated mutualistic association between a species of fungus and a species of either a green algae or a blue-green algae. Although lichens come in a wide variety of forms and structures, all lichens are essentially a sandwich with a layer of fungi on the outside with a filling of an algal species on the inside. The fungus species attaches the lichen structure to the log, rock, or brick wall it lives on and absorbs nutrients from the environment. It addition the fungus forms a protective envelope for the algae preventing the algae from drying out. The algae in its turn uses the nutrients absorbed by the fungus and the carbon dioxide produced to photosynthesize. The sugars and oxygens produced by the algae are, in turn, used for food by the fungus. This highly successful mutualistic relationship between the two species allows lichens to colonize habitats that are hardly survivable by other plant and animal species.

Symbiotic Relationships Organisms and Their Relationships Symbiotic Relationships Commensalism One organism benefits, the other is unaffected Anemonefishes (sometimes called clownfishes) are a beautiful group of tropical, reef fishes from the Pacific and Indian Oceans. Almost all of the species belong to the genus Amphiprion. These fishes are unusual because they have a close relationship with sea anemones. Sea Anemones belong the class Anthozoa which includes the hydras, corals, and jellyfish. The simple structure of the sea anemone consists of a hollow cylinder surrounded by a crown of tentacles. The tentacles are equipped with specialized cells called nematocysts. Nematocysts are shaped and function like small harpoons and contain a poison sufficient to paralyze or kill small fish and other reef inhabitants. The anemonefish lives among the forest of tentacles of an anemone and is protected from potential predators not immune to the sting of the anemone. The anemonefish is protected from the sting of the anomone tentacles by a substance contained in the mucous on its skin. The exact nature of this protective substance is not known, but is believed to be a combination of a partial natural secretion and chemicals the fish harvests by rubbing up against the anemone's tentacles. What ever the case may be, the anemone treats the fish as part of itself and does not sting it. Some consider this relationship to be a case of mutualism, claiming that the anemonefish chases away other fish that might prey on the anemone. However this aspect of the relationship is not well documented. Barnacle are sedentary, highly modified crustaceans resembling conical pyramids. Barnacles live by using long, feathering appendages to sweep the surrounding water for small, free-floating organisms. The critical resource for barnacles is a place to stay. Barnacles attach to rocks, ships, shells, whales, and just about anywhere else they can gain a foothold. In the example on the left the two barnacles are attached to the shell of a scallop. The barnacle gains a place to live and, presumably, the scallop is not harmed by the presence of the barnacles. Therefore the relationship is commensalism.

Symbiotic Relationships Organisms and Their Relationships Symbiotic Relationships Parasitism One organism benefits, the other is harmed Tick, tapeworm, mistletoe

Symbiotic Relationships Read Section 3-1 pgs. 63-65 Read Section 4-2 pgs. 90-93