2. Ch. 2: Interactions Within Ecosystems GROUPS OF LIVING THINGS INTERACT WITHIN ECOSYSTEMS ORGANISMS CAN INTERACT IN DIFFERENT WAYS ECOSYSTEMS ARE ALWAYS CHANGING

3. Groups of Living Things Interact Within Ecosystems ORGANISMS OCCUPY SPECIFIC LIVING AREAS THE ENVIRONMENT CAN BE ORGANIZED INTO FIVE LEVELS PATTERNS EXIST IN POPULATIONS

4. SPECIFIC LIVING AREAS Scientists group living things according to shared characteristics; smallest grouping is SPECIES: so similar can produce offspring that also can produce offspring. POPULATIONS: group of same species living in particular area; populations of many different species may live in same area.

5. SPECIFIC LIVING AREAS HABITAT & NICHE: habitat = physical location filled with different species, each depending on habitat’s resources to meet it’s needs. Different populations interact with each other. Each organism has a role to play in the habitat, called it’s niche. (plants give food & nesting sites for animals, which leave fertilizing droppings and spread plants seeds). Usually no 2 species will fill the exact same niche. (We all have our unique abilities & purposes to fill!) COMMUNITIES: a group of populations that live in a particular area & interact with one another. The Galapagos Island community includes Cacti, iguanas, & crabs.

6. SPECIFIC LIVING AREAS

7. Environments can be Organized into 5 Levels BIOME: very generally describes climate & types of plants found in similar places around the world. ECOSYSTEM: many ecosystems found in each biome; includes organisms & their local environment; living & non-living factors interact to form stable system. COMMUNITY: the living parts of an ecosystem. Different plants, animals, & other organisms interact with each other within a community. POPULATION: a group of organisms of the same species living in the same area. ORGANISM: a single individual animal, plant, fungus, or other living thing.

9. Patterns in Living Space Certain plants & animals keep specific distances apart from each other (Mojave desert bushes, bluebirds-100m). Distribution of organisms in a habitat is often based on how they meet their needs. Herring swim in schools & wildebeests roam African grasslands in herds. Rely on grouping for their safety, so better chance of survival.

10. Patterns in Time Yellow jackets rarely seen in spring, but often in fall. (Queen lays eggs in spring and keeps doing this all summer as population grows, many by fall; in winter, all die except for Queen to continue next year). Many birds migrate south in winter for more food, so population changes from season to season. Some Cicadas appear only every 17 years. No other species can rely on them as food source, so they survive long enough to lay eggs when they do appear.