560 likes | 931 Views
APES Notes – Chapter 8. Mrs. Sealy. Community Ecology: Structure, Species Interactions, Succession, and Sustainability. General Types of species Native: species that normally live and thrive in a particular ecosystem
E N D
APES Notes – Chapter 8 Mrs. Sealy
Community Ecology: Structure, Species Interactions, Succession, and Sustainability • General Types of species • Native: species that normally live and thrive in a particular ecosystem • Non-native species: species that migrate into an ecosystem or are deliberately or accidentally introduced into an ecosystem by humans. Also known as: exotic, alien species, invasive or introduced
Problems caused by Non-native species: • the non-natives have no natural enemies so they can thrive in the new ecosystem and crowd out the native species: Examples
Indicator Species: • species that serve as early warnings that a community or ecosystem is being damaged or changed: • Birds are good indicators because: Birds are good indicators because: very sensitive to environmental changes • Trout and macro-invertebrates are good indicators of: water quality • Amphibians indicate: chemical pollution
Keystone species: • species that play a pivotal role in the structure, function, and integrity of an ecosystem because • Their strong interactions with other species affect the health and survival of these species • They process material out of proportion to their numbers and biomass • Keystone species: • Pollinate • Scatter seeds • Modify habitats • Predation to control prey populations • Help plants get nutrients • Recycle animal waste • Examples: bees, sharks, alligators, bats, dung beetles, sea otter elephant
Species in an ecosystem who are very important are called… • Keystone species • Indicator species • Non-native species • Exotic species 0 of 20 Answer Now
Species that serve as early warnings for ecosystem imbalance • Keystone species • Indicator species • Non-native species • Exotic species 0 of 20 Answer Now
Which term means the opposite of the others? • Non-native • Exotic • Native • Alien 0 of 20 Answer Now
Species Interactions • Five Types of Interactions: • Competition: Two or more animals competing for the same resources. Two Types: • Intraspecific: competition between members of the same species • Interspecific: competition between members of two different species
Territoriality: • when animals mark an area around their home or nesting area. This has disadvantages because animals exclude other males from breeding and: they expend a lot of energy defending their territory
The more a species niche overlaps, then the more competition • Interference Competition: when one species limits another species access to some resource regardless of its abundance. Examples: • When a larger more established cat interferes with another cat accessing food by swatting at it every time it tries to feed
Exploitation Competition: competing species have roughly equal access to a specific resource, but differ in how fast they exploit it. Examples: • An older more established cat will gobble up all the food before the other animal has a chance to eat
Competitive Exclusion Principle: • No two species can occupy the same niche indefinitely in a habitat where there is not enough of a particular resource to meet the needs of both species.
High Relative population density Low 0 2 4 6 8 10 12 14 16 18 Days Each species grown alone Paramecium aurelia Paramecium caudatum Fig. 8.8a, p. 182
High Paramecium aurelia Relative population density Paramecium caudatum Low 0 2 4 6 8 10 12 14 16 18 Days Both species grown together Fig. 8.8b, p. 182
If one kitty gobbles up all the food so the other does not get any • Interference competition • Interspecific competition • Exploitation competition • Territoriality 18 of 20 Answer Now
Competition between two members of the same species • Interspecific • Intraspecific • Exploitation • Interference 0 of 20 Answer Now
Avoiding Competition: • Resource Partitioning: dividing up of scarce resources so that species with similar needs use them at different times, in different ways, or in different places. “Share the wealth” Examples: being nocturnal or diurnal
Character Displacement: • Species develop characteristics over time through evolution to allow them to exploit different resources Examples: Darwin’s finches each developed a different shaped beak to exploit different food types
Herring gull is a tireless scavenger Brown pelican dives for fish, which it locates from the air Black skimmer seizes small fish at water surface Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Ruddy turnstone searches under shells and pebbles for small invertebrates Flamingo feeds on minute organisms in mud Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Piping plover feeds on insects and tiny crustaceans on sandy beaches Louisiana heron wades into water to seize small fish Fig. 8.9, p. 182
Predator-Prey Interactions: • members of one species feed directly on all or part of a living organism or other species. They do not live on or in the other species. One species is clearly harmed and the other clearly benefits. However predation can be a good thing for the population of prey species as predators often weed out the sick and dying animal thereby reducing competition amongst the prey species.
Predators • Predators have characteristics that help them catch prey, such as: • Running fast, ex. jaguar • Good eyesight, Ex. hawk • Hunting in packs, ex. coyote • Camouflage for ambush, ex. frog
Prey • Prey have characteristics that help them escape predators, such as: • Run fast • Good sense of smell and eyesight to alert them to the presence of predators • Protective shell • Spines • Camouflage • Chemical warfare like poisonous skin • Foul smells • Bad tasting • Warning coloration • Mimicking a predator • Examples:
African stoneplants Canyon tree frog Bombardier beetle Poison dart frog Foul tasting monarch butterfly Viceroy butterfly mimics monarch butterfly Hind wings of io moth resemble eyes of a much larger animal When touched, the snake caterpillar changes shape to look like the head of a snake Fig. 8.12, p. 186
Symbiosis: • a long lasting relationship in which species live together in an intimate association. • Parasitism: when one species feeds on part of another organism (host) by living on or in the host. In this relationship the host is harmed and the parasite benefits. Example:
Which of the following predators avoid competition by being active at different times? • Snakes and hawks • Lions and tigers • Owls and hawks • Zebras and antelopes 0 of 20 Answer Now
The obvious relationship illustrated by a food chain is.. • Predation • Parasitism • Mutualism • Commensalism 0 of 20 Answer Now
Prey are least likely to defend themselves against predators by.. • Camouflage • Acute senses of smell and hearing • Protective shells • Pursuit and ambush 0 of 20 Answer Now
Mutualism: • symbiotic relationship in which both species involved benefit from the relationship. Ways in which this happens are pollination, providing food, and providing shelter. Examples: Fig. 8.13, p. 187
Commensalism: • a symbiotic relationship in which one species benefits and the other species is neither helped nor harmed. For example: epiphytes
The Win-Win relationship in nature. • Commensalism • Parasitism • Competition • Mutualism 0 of 20 Answer Now
A relationship in which one organism feeds in or on another • Parasitism • Mutualism • Commensalism 0 of 20 Answer Now
Ecological Succession • Succession: One characteristic of all ecosystems is that they change over time. This is called ecological succession. There are two types of succession: Primary and secondary.
Primary Succession: • Succession that starts with an essentially lifeless area where there is no soil or bottom sediment in an aquatic area. Examples include new lava or an abandoned parking lot. Succession happens in stages: • Pioneer species move in and make soil: Ex. Lichens and mosses • When enough soil is made and spread out then plants that are small and close to the ground move in. These plants can live under harsh conditions and usually have short lives. They are called early successional species. Examples: heath and shrubs • After hundreds of years there is enough soil for Mid-successional species. Examples: pine trees • As the Mid-successional plants grow they create enough shelter for Late successional species such as: spruce and fir trees
Exposed rocks Lichens and mosses Balsam fir, paper birch, and white spruce climax community Jack pine, black spruce, and aspen Heath mat Small herbs and shrubs Time Fig. 8.15, p. 188
Secondary Succession: • begins in an area where the natural community of organisms has been disturbed or destroyed, but the soil remains. For example abandoned farms, burned or cut forests, and heavily polluted streams. Secondary succession occurs in the same way as primary starting with pioneer species and ending with late successional species.
Mature oak-hickory forest Young pine forest Shrubs Perennial weeds and grasses Annual weeds Time Fig. 8.16, p. 189
Succession • Descriptions of succession usually focus on plants, but animals also change with succession as different types of plants become available for food and shelter. • Early successional species: • Mid-successional species: • Late successional species: • Wilderness species:
Early Successional Species Rabbit Quail Ringneck pheasant Dove Bobolink Pocket gopher Midsuccessional Species Elk Moose Deer Ruffled grouse Snowshoe hare Bluebird Late Successional Species Turkey Martin Hammond’s Flycatcher Gray squirrel Wilderness Species Grizzly bear Wolf Caribou Bighorn sheep California condor Great horned owl Ecological succession Fig. 8.17, p. 190
Disturbances can Affect Succession • Some disturbances can be beneficial in the long run like fire, because they increase biodiversity, clear out excess brush, renew nutrients and encourage other species to grow • Some catastrophic disturbances can convert the ecosystem back to a lower level of succession • We used to think that succession was predictable and that it would continue until a stable climax community was reached. We now know that is false. We cannot predict the course of a given succession or view it as preordained progress toward an ideally adapted climax community. Succession is an ongoing struggle.
The stability of an ecosystem depends on three things: • Inertia: the ability of species to resist change • Constancy: the ability of a population to keep its numbers within the limits imposed by availability of natural resources. • Resilience: the ability of a living system to bounce back after a disturbance
Species diversity 0 100 Percentage disturbance Fig. 8.18, p. 192
Populations with more biodiversity are more stable. More biodiversity means greater primary productivity and more resilience. Examples: Don’t put all your eggs in one basket
Grizzly bear NORTH AMERICA St. Lawrence beluga whale Eastern cougar Humpback whale More than 60% of the Pacific Northwest coastal forest has been cut down Spotted owl Fish catch in the north-west Atlantic has fallen 42% since its peak in 1973 Black footed ferret 40% of North America’s range and cropland has lost productivity Florida panther Chesapeake Bay is overfished and polluted California condor Manatee Kemp’s ridley turtle Much of Everglades National Park has dried out and lost 90% of it’s wading birds Hawaiian monk seal Golden toad Coral reef destruction Half of the forest in Honduras and Nicaragua has disappeared Every year 14,000 Square kilometers of Rain forest is destroyed in the Amazon Basin Columbia has lost one-third of its forest Mangroves cleared in Equador for shrimp ponds Black lion tamarin PACIFIC OCEAN SOUTH AMERICA Little of Brazil’s Atlantic forest remains ATLANTIC OCEAN Southern Chile’s rain forest is threatened Environmental degradation Vanishing biodiversity Endangered species Fig. 8.19a, p. 194 6.0 or more children per woman
Many parts of former Soviet Union are polluted with industrial and radio- active waste ASIA Poland is one of the world’s most polluted countries Central Asia from the Middle East of China has lost 72% of range and cropland Giant panda Imperial eagle EUROPE Japanese timber imports are responsible for much of the world’s tropical deforestation Area of Aral Sea has Shrunk 46% Mediterranean 640,000 square kilometers south of the Sahara have surned to desert since 1940 Saudi Arabia Deforestation in the Himalaya causes flooding in Bangladesh Asian elephant Liberia Oman Kouprey Eritrea AFRICA Mali Yemen 90% of the coral reefs are threatened in the Philippines. All virgin forest will be gone by 2010 India and Sri Lanka have almost no rain forest left Burkina Faso Niger Benin Ethiopia Chad Golden tamarin Sierra Leone Nigeria Togo Congo Rwanda Burundi Uganda Sao Tome Somalia In peninsular Malaysia almost all forests have been cut 68% of the Congo’s rain forest is slated for cleaning Queen Alexandra’s Birdwing butterfly Angola Indonesia’s Coral reefs are threatened and mangrove forests have been cut in half Zambia Nail-tailed wallaby INDIAN OCEAN Aye-aye Fish catches in Southeast Atlantic has dropped by more than 50% since 1973 AUSTALIA Black rhinoceros Madagascar has lost 66% of its tropical forest Much of Australia’s Range and Cropland has turned to desert Blue whale A thinning of the ozone layer occurs over Antarctica during summer Fig. 8.19b, p. 195 ANTARCTICA