Presentation on theme: "Chapter 6 (pgs. 88-107) Mrs. Paul. All species interact and a change in the relationships may change a population and thus the food web. Relationships:"— Presentation transcript:
Predators: consumers that actively hunt other organisms. Example: praying mantis (predator) eating a dragon fly (prey) Prey: organisms that a predator feeds upon Example: a snake (predator) eating a praying mantis (prey). The size of both populations influence each other
Parasitism: relationship in which one organism feeds on the tissues or body fluids on another. Host: the organism on which the parasite feeds. Parasites are harmful and have the potential to kill their host. Depends on the host for many functions. Examples: fleas, ticks, lice, protists, tapeworms.
Ecological Succession: gradual process of change and replacement of some or all of the species in a community. May take hundreds or thousands of years. Each new community makes it harder for the previous community to survive. Two main types: 1. Primary Succession 2. Secondary Succession
Primary Succession: sequence of communities forming in an originally lifeless habitat. Occurs in habitats without life. Examples: cooled lava field, bare rock after retreating glacier.
1.Formation of soil from exposed rocks as lichen and weather break them down. -Lichen: fungus and alga living in a mutualistic relationship. -Pioneer community: first community to colonize new habitat. 2. Grasses and small plants begin to grow from seeds carried by wind and animals. 3. Growth of non-woody plants with deep roots (shrub community). 4. Growth of pine forest 5. Growth of hardwood forest. -Climax community: community that does not undergo further succession.
Secondary succession: succession that occurs where a community has been cleared by a disturbance that does not destroy the soil. Examples: fires, storms, human disturbances. Frequently disturbed habitats may never reach the climax community. Example: grassland frequently burned by fires.
1. Fast-growing grasses and non-woody plants. 2. Larger shrubs grow. 3. Pine Forest 4. Hardwood Forest
Starts with a body of water that is low in nutrients. Leads to a fertile meadow as the lake fills in with vegetation over time.
Populations of new organisms can adapt quickly to fill new niches or to form new species.
1. How does primary succession differ from secondary succession? 2. What is a climax community? 3. Suppose humans put out all the fires in a large area of grassland over a period of 100 years. What would happen to the grassland community?
If ecosystems are not balanced, they do not survive. Disruptions are normal; they trigger change in the ecosystem. Chaos Theory Suggests that ecosystems may be sensitive to very small changes.
We divide the ecosystems on Earth into several categories. Biome: major type of ecosystem with distinctive temperature, rainfall, and organisms. Terrestrial (land) biomes Type of biome depends on average temperature and amount of precipitation the area receives. Aquatic (water) biomes Determined by water depths, nutrients, and nearness to land.