1. Competition and predation are two interactions Competition: two organisms fight for the same limited resource. –Intraspecific: between organisms of the same species –Interspecific: between organisms of different species

2. Predation: one organism captures and eats another.

3. SYMBIOSIS: Close relationships between organisms –1) Mutualism: both organisms benefit Ex: Bats and the plants they help pollinate Ex: Clownfish & Sea anemone

4. –2) Commensalism: one organism benefits, the other is unharmed Ex: Tiny mites in our eyelashes don't hurt us and they get food Human Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle. Demodicids Eyelash mites find all they need to survive in the tiny follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. + Organism benefits + Ø Ø Organism is not affected Commensalism

5. –3) Parasitism: one organism benefits, the other is harmed Ectoparasites: outside the body (ex: leeches) Endoparasites: inside the body (ex: hookworms) Organism benefits 0 _ Organism is not affected Hornworm caterpillar The host hornworm will eventually die as its organs are consumed by wasp larvae. Braconid wasp Braconid larvae feed on their host and release themselves shortly before reaching the pupae stage of development. _ Parasitism + 0

6. NOW Practice: Relationships in Ecosystems 1) 2 kangaroos fighting 2) Snake eating a lizard 3) Buffalo with birds on its head 4) Bee on a flower

7. KEY CONCEPT Life in an ecosystem requires a source of energy.

8. Producers provide energy for the other organisms in an ecosystem. Producers get their energy from non-living resources. Also called autotrophs: make their own food.

9. Producers get their energy from different sources Photosynthesis: uses sunlight as an energy source. Chemosynthesis: uses chemicals as an energy source. carbon dioxide + water + hydrogen sulfide + oxygen sugar + sulfuric acid

10. Consumers must obtain their energy – they can not make it Consumers get their energy by eating other living or once- living resources. Also called heterotrophs: they feed off of other things.

11. FOOD CHAIN: a model that shows feeding relationships. Food chains link species by their feeding relationships. Follows the connection between one producer and a chain of consumers within an ecosystem. DESERT COTTONTAILGRAMA GRASSHARRIS’S HAWK

12. FOOD WEB: a more complex model  A food web shows a network of feeding relationships  Emphasizes energy flow  An organism may have multiple feeding relationships in an ecosystem.

13. VOCAB Add the following to your vocab sheets: ABIOTIC – You already know this one! Example sentence: Rocks, water, and soil are all abiotic ORGANIC MATTER – Example sentence: Plants and animals are all made of organic matter