1 / 19

CHAPTER 36 Communities and Ecosystems

CHAPTER 36 Communities and Ecosystems. Modules 36.1 – 36.4. Dining In. Wasps and Pieris caterpillars form an unusual three-step food chain The 4-mm-long wasp Apanteles glomeratus stabs through the skin of a Pieris rapae caterpillar and lays her eggs

rtiffany
Download Presentation

CHAPTER 36 Communities and Ecosystems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHAPTER 36Communities and Ecosystems Modules 36.1 – 36.4

  2. Dining In • Waspsand Pieris caterpillars form an unusual three-step food chain • The 4-mm-long wasp Apanteles glomeratus stabs through the skin of a Pieris rapae caterpillar and lays her eggs • The caterpillar will be destroyed from within as the wasp larvae hatch and nourish themselves on its internal organs

  3. A female ichneumon will pierce the caterpillar and deposit her own eggs inside of the Apanteles larvae • Ichneumon wasps can detect when a Pieris caterpillar contains Apanteles larvae

  4. Usually, only the chalcids will emerge from the dead husk of the caterpillar • Finally, yet another wasp, a chalcid, may lay its eggs inside the ichneumon larvae

  5. A biological community derives its structure from the interactions and interdependence of the organisms living within it • Ecosystem functioning depends on the complex interactions between its community of organisms and the physical environment

  6. 36.1 A community is all the organisms inhabiting a particular area • All the organisms in a particular area make up a community • A number of factors characterize every community • Biodiversity • The prevalent form of vegetation • Response to disturbances • Trophic structure (feeding relationships) Figure 36.1

  7. Biodiversity has two components • Species richness, or the total number of different species in the community • The relative abundance of different species • Biodiversity is the variety of different kinds of organisms that make up a community

  8. STRUCTURAL FEATURES OF COMMUNITIES 36.2 Competition may occur when a shared resource is limited • Interspecific competition occurs between two populations if they both require the same limited resource • A population's niche is its role in the community • The sum total of its use of the biotic and abiotic resources of its habitat

  9. Populations of two species cannot coexist in a community if their niches are nearly identical • The competitive exclusion principle Hightide Chthamalus Balanus Ocean Lowtide Figure 36.2

  10. One of the populations, using resources more efficiently and having a reproductive advantage, will eventually eliminate the other • Natural selection may lead to resource partitioning • Competition between species with identical niches has two possible outcomes

  11. 36.3 Predation leads to diverse adaptations in both predator and prey • Predation is an interaction where one species eats another • The consumer is called the predator and the food species is known as the prey • Parasitism can be considered a form of predation

  12. This process of reciprocal adaptation is known as coevolution • Example: Heliconius and the passionflower vine • As predators adapt to prey, sometimes natural selection also shapes the prey's defenses Eggs Sugardeposits Figure 36.3A

  13. Mechanical defenses, such as the quills of a porcupine • Prey gain protection against predators through a variety of defense mechanisms

  14. Animals with effective chemical defenses are often brightly colored to warn predators • Example: the poison-arrow frog • Chemical defenses are widespread and very effective Figure 36.3B

  15. Example: the gray tree frog • Camouflage is a very common defense in the animal kingdom Figure 36.3C

  16. Batesian mimicry occurs when a palatable or harmless species mimics an unpalatable or harmful one • The mimicry can even involve behavior • This hawkmoth larva puffs up its head to mimic the head of a snake Figure 36.3D

  17. Müllerian mimicry is when two unpalatable species that inhabit the same community mimic each other • Example: the cuckoo bee and the yellow jacket Figure 36.3E

  18. 36.4 Predation can maintain diversity in a community • A keystone species exerts strong control on community structure because of its ecological role • A keystone predator may maintain community diversity by reducing the numbers of the strongest competitors in a community • This sea star is a keystone predator Figure 36.4A

  19. Predation by killer whales on sea otters, allowing sea urchins to overgraze on kelp • Sea otters represent the keystone species Figure 36.4B

More Related