1 / 22

Chapter 46

Chapter 46. Communities & Biodiversity. Communities. Multicelled organism Population Community Ecosystem Biosphere. Communities.

dreama
Download Presentation

Chapter 46

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 46 Communities & Biodiversity

  2. Communities • Multicelled organism • Population • Community • Ecosystem • Biosphere

  3. Communities • An interacting group of various species in a common location. For example, a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community.

  4. Communities • Structure arises from… • Physical & chemical conditions of habitat • Availability of food & resources (type, amount, etc.) • History of habitat & species • Traits that help species survive in habitat • Interactions among species • Physical disturbances

  5. Communities • Niche— “profession” of a species that sets it apart from other species. • Fundamental niche—Would happen even in absence of competitors or other limiting factors. • Realized niche—Actual position taking into account competition & limiting factors; can change over time.

  6. Species Interactions • Commensalism • One species helped, other species not affected • Bird & tree • Barnacles & whales • Remoras & sharks

  7. Species Ineractions • Mutualism • Both species benefit • Ants & aphids • Pollen & insects • Sea anemones & fish • Bacteria & larger organisms • Horses & cecal bacteria • Termites & hindgut bacteria

  8. Species Interactions • Parasitism • One species benefits, other is harmed • Endoparasite—live inside the host • Roundworms • Malaria (Plasmodium) • Ectoparasite—live on the host • Lice • Ticks • Brood parasite—manipulate other animals to raise young • Cuckoos • Cowbirds • Cuckoo bees & wasps

  9. Species Interactions • Parasitism (cont.) • Drain nutrients from host • Using resources that host needs • Weakened hosts more easily preyed upon • Weakened hosts may not be able to forage • Hosts may die

  10. Species Interactions • Predation • One species kills and feeds on another species • Balanced relationship • As prey increases or decreases, so does predator

  11. Predator-Prey Relationship • Predation a strong factor in natural selection • Some modifications in prey make them less likely to be preyed upon • Predators also undergo selection to overcome prey’s defenses

  12. Prey Defenses • Camouflage • Blend into surroundings • Avoid being seen (predator & prey)

  13. Prey Defenses • Chemical Defense • Bad-tasting—Monarch butterfly • Toxic—Poison dart frog, scorpionfish • Venomous—Coral snake • Irritant—Skunk, bombardier beetle • Often have bright coloration or specific behavior as a warning

  14. Prey Defenses • Mimicry • Closely resemble dangerous or unpalatable species • Predator avoids due to perceived danger

  15. Prey Defenses • Physical Defense • Shell, armor—turtles, armadillos • Spines, spikes—porcupines, hedgehogs, lizards • Horns, antlers—rhinocerous, deer

  16. Prey Defenses • Startle/Surprise Defenses • Look fearsome or larger • False eye spots—moths, caterpillars • Neck frills—lizards, birds • “Fluffing” hair or feathers—birds, mammals • Vocal displays—hissing cockroach, cats, growling dogs

  17. Predator Armament • Camouflage (tiger, leopard) • Lures (anglerfish, snapping turtle) • Heat sensors (pythons, vipers) • Pack behavior (wolves, lions)

  18. Community Stability • Communities usually reach stability • Can be upset by new additions or subtractions • Keystone species—species that has disproportionately large effect relative to its abundance • Predators • Sea star experiment • Sea stars prey on several species • Remove sea stars • Mussels take over, crowd out other species • Sea otters & sea urchins

  19. Community Stability • Keystone species (cont.) • Engineers • Change the environment through actions • Grizzly bears—transfer oceanic nutrients (salmon) to forest ecosystem • Up to half of salmon captured ends up on forest floor • Beavers—transform stream to pond or swamp • Elephants—destroy trees, make room for grass

  20. Community Stability • Introduced species • Can upset balance • May not have natural predators • May not have competition • Rabbits in Australia • 24 introduced in 1859 for hunting • By 1869 could kill 2,000,000 without affecting population • Currently over 100 million • Eat native plants, leads to large erosion

  21. Community Stability • Introduced species (cont.) • Zebra mussels • Native to Russia & Caspian Sea • First detected in Great Lakes in 1988 • Suspect were attached to ship ballast, anchors, chains • Invaded waterways • Kill & outcompete native mussels • Damage boats, harbors, power plants

More Related