Populations & Communities Obj: 11B

1. Populations & CommunitiesObj: 11B Investigate and analyze how organisms, populations, and communities respond to external factors.

2. What is an organism? • An individual living thing, such as a bacterium, protist, fungi, plant, or animal.

3. What is a population? • A group of one species of organisms that live together in a certain area. Examples: • Humans living in the city of Houston • Tree frogs living in a forest

5. What is a community? • A group of populations of different species that interact with one another. Example: • Populations of tree frogs, snakes, birds, as well as other animals and plants all living together on a tropical island

7. What is an ecosystem? • Communities in the environment • Includes abiotic (non-living) and biotic (living) factors. Example: the tropical island

9. How do organisms respond to external factors? • When a rabbit senses that a predator is near…

10. It runs away or hides in a burrow

11. When a skunk feels threatened…

12. It sprays its attacker with a foul-smelling liquid

13. When an opossum is attacked…

14. It curls into a ball, and pretends to be dead.

15. Plants that grow as vines, such as pumpkin and ivy, produce tendrils that can wrap around surfaces

16. Roots of plants tend to grow toward wet soil, while the leaves grow toward light

17. How do populations respond to external factors? • Predator & prey relationships • Competition among predators • Invasive species outcompete natives • Disease

18. Predation

19. Competition

20. Invasive species • Asian carp were introduced to Michigan lakes to control algae. • Now introduced species outcompeting native fish for food.

22. Pythons in the Everglades in Florida

25. Disease

29. How do communities respond to external factors? What happens to the snake population when the toad population dies out due to disease?

30. Volcano Explosion

33. Oil Spills

36. The Role Microorganisms 11C: Summarize the role of microorganisms in both maintaining and disrupting the health of both organisms and ecosystems.

37. What is a microorganism? • Any organism that cannot be seen without the aid of a magnifying glass or microscope • Examples – bacteria, protists, fungi • Found in almost every habitat on Earth

39. How can microorganisms maintain the health of other organisms?

40. Mutualistic Relationships • Microorganism gains benefits such as a warm environment to inhabit and gain nutrients • Animal or plant may gain benefits such as protection from other microorganisms or a supply of enzymes they need but cannot produce

41. Example – bacteria living in guts of termites & cows to produce enzymes to digest cellulose • Example - Fungi & plants form relationship called mycorrhizae.

42. The Fungi collect water & minerals and deliver them to plant roots • The Plants provide the fungi with nutrients made through photosynthesis.

44. Example – Plants called legumes contain bacteria of the genus Rhizobium in structures on their roots called nodes. • The Rhizobium fixes atmospheric nitrogen so that is is available for plants to use.

46. How can microorganisms disrupt the health of organisms?

47. Parasitic Relationships • Some microorganisms causes diseases in a host. These microorganisms are called pathogens. • Pathogens cause a disease by killing the host cells, releasing toxins, or interfering with the processes within the host’s body.

48. Lyme Disease • Caused by at least three species of bacteria belonging to the genus Borrelia.

49. Tetanus • Caused by the bacteria Clostridium tetani.

50. Strep Throat • Caused by the bacteria Streptococcus pyogenes.