COMMUNITIES

1. COMMUNITIES How do populations of many species interact in a community?

2. Habitat • A habitat can be described as all of the biotic and abiotic factors in the area where an organism lives. Lemurs spend most of their time in trees, with the exception of the ringtail lemur. They are mostly active during the day, and tend to live in groups.

3. Niche • The unique position occupied by a species, both in terms of its physical use of its environment and its function in an ecological community. Beavers live in riparian systems. They keep these systems healthy and in good repair. By cutting down trees, Beavers maintain a reliable pool of water for many species, and they create a small wetland in the process. Clearing out trees allows young trees to grow. Their lower branches give easier access to many species.

4. Niche The Aye Aye is omnivorous. It eats grubs, fruit, leaves, nectar, and fungi. • Food • The type of food a species eats, how a species competes for food, and where it fits in the food web are all part of its niche. • Abiotic Conditions • The range of conditions, such as air temperature and amount or water, that a species can tolerate. • Behavior • The time a day a species is active as well as where and when it reproduces are factors. The Aye Aye lives in Madagascar, preferring canopy of the tropical rainforest. Aye Aye’s are nocturnal, and mostly solitary, though their home ranges (up to 80 acres) often overlap. Aye Ayes are dedicated mothers, and will play ‘peek-a-boo’ with their babies.

5. Niches • Fundamental Niche • The entire range of conditions where an organism or species can survive

6. Niches • Realized Niche • The actual niche a species occupies.

7. Niche Interactions • Competitive Exclusion • Competition between two species that use the same niche. • When resources are scarce--someone has to die or move on. • No two species can occupy the same niche.

8. SYMBIOSIS

9. Symbiosis • The relationship between different species living in close association with one another • There are 5 types of symbiosis • Predation • Parasitism • Competition • Mutualism • Commensalism

10. Predation • When one organism hunts and kills another organism for food. • Predator • captures, kills, and consumes another individual • Prey • the individual that is killed • Wolves Hunting

11. Adaptations for Predators • Rattlesnakes have acute smelling and heat-sensitive pits • Spiders build webs • Carnivores have sharp teeth • Tigers have striped camouflaged coat

12. Adaptations for Animal Prey • Poisonous and warn predators with bright colors • Poison dart frog • Mimicry: a harmless species resembles a poisonous or distasteful one • This similarity can be in appearance, behavior, sound, scent and even location, with the mimics found in similar places to their models • King snake resembles coral snake. • Coral snakes are poisonous. • Red on yellow-kill a fellow. • Red on black-friend of Jack. • Stay in herds; run away • Camouflage • Mimic Octopus King Snake Coral Snake

13. Adaptations of Plants • Physical defenses • Sharp thorns, spines, sticky hairs, tough leaves • Chemical defenses (secondary compounds) • Poisons can be irritating or bad-tasting • Stychnine nicotine (toxic to insects), poison ivy, and poison oak are some examples. • Medicine can be manufactured using these plants. • Morphine, atropine, codeine, taxol, and quinine, all come from plants.

14. Parasitism • One organism is harmed (the host)while the other organism benefits (the parasite) • Usually does not result in death • Two types • Ectoparasites (external) • Endoparasites (internal) • Parasites have many adaptations • Honeyguide Birds--Brood Parasites • Cowbird-Brood Parasite • Zombie Ants • Zombie Snails

15. Competition • Results from fundamental niche overlap • Two or more species use the same limited resource • Competitive exclusion: one species is eliminated from a community • Interspecific competition • Occurs when two different species compete for a limited resource. • Intraspecific competition • When members of the same species compete for limited resource. • Bear vs. Bald Eagle

16. Competition and Community Structure • Resource partitioning • A pattern of resource use in which species reduce their use of shared resources • Many species of warblers eat insects. If two species of warbler lived in the same area, they would compete for the same food, and each population would suffer. To limit competition, one warbler will eat at the top of a tree, and another will eat near the bottom of a tree.

17. Competition and Community Structure • Character displacement • Evolution of anatomical differences that reduce competition between similar species • Example: Beak size in finches

18. Competition and Community Structure • Ecological Equivalents • These are species that occupy the same niche, but live in different geographical regions. • Ex. Poison Frogs • Mantella Frog of Madagascar • Poison Dart Frog of South America • Both have brightly colored skin that secretes a highly poisonous toxin to ward off predators. • Both prey on similar insects, and live in similar habitats. Poison Dart Frog Mantella Frog

19. Mutualism • Cooperative relationship in which both species derive some benefit For the bees, the pollen and nectar from many flowers is an important source of fats, proteins, vitamins, and minerals. The nectar is a source of energy. As bees travel from one blossom to another, pollen clings to their fuzzy bodies. It is then transferred to the other flowers of the same species. This pollinates or fertilizes the plant. Plants then can produce their own fruits and seeds. Mutualism The acacias provide shelter for ants in the thorns and nectar in extrafloral nectaries for their symbiotic ants. In turn, the ants protect the plant by attacking large mammalian herbivores and stem-boring beetles that damage the plant.

20. Commensalism • Interaction in which one species benefits; the other is neither helped nor harmed • Crocodile and Hippo The Cattle Egret feeds on a wide range of prey, particularly insects, especially grasshoppers, crickets, flies (adults and maggots), and moths, as well as spiders, frogs, and earthworms. The species is usually found with cattle, in this case cape buffalo, and other large grazing and browsing animals, and catches small creatures disturbed by the mammals

21. Ecosystem Resiliency How do species vary in richness and diversity? And how does that help ecosystems survive disaster?

22. Species Richness and Diversity • Species richness • the number of species a community contains

23. Species Richness and Diversity • Species diversity • an index combining the number and relative abundance of different species in a community • Interactions between organisms and the number of species in an ecosystems add to the resiliency of an ecosystem.

24. Patterns of Species Richness • Species richness varies with latitude (distance from the equator) • The closer a community is to the equator, the more species it will contain • Why? • Tropical habitats are older (not disturbed by the ice ages) • More light for photosynthesis

25. Species Richness

26. Species Richness

27. The Species-Area Effect • Larger areas usually contain more species than smaller areas • Why? • Larger areas usually contain a greater diversity of habitats • So, reducing the size of a habitat reduces the number of species it can support • Most often applied to islands

28. Species Interactions and Species Richness • Interactions among species sometimes promote species richness • Predators can prevent competitive exclusion from occurring among their prey • Mussles are fierce competitors that take over space and exclude all other species. Sea stars eat mussels and allow a variety of other species to live in intertidal zones.

29. Sea Stars eating Mussels

30. Keystone Species • Keystone species • a species that is critical to an ecosystem • Affects the survival and number of many other organisms in a community • Grizzly Bears • Salmon come into the rivers from the oceans. • Grizzly bears eat the salmon. • Grizzly bears poo nutrient rich poo and leave behind partially eaten carcasses in the forest. • This feeds the forest.

31. Community Stability • How a community responds to a disturbance (like drought or insect pests) • Species richness improves a community’s stability

32. Succession What happens after a disturbance like a fire or landslide?

33. Succession • Succession: • the gradual, sequential re-growth of species in an area • There are 2 types of succession • Primary succession • Secondary succession • Primary and Secondary Succession

34. Pioneer Species • Pioneer species • the first species to colonize a new habitat • What adaptations would such species have? • Tend to be small, fast-growing, and fast-reproducing • Good at dispersing seeds

35. Primary Succession • Primary succession • development of a community in an area that has not previously supported life • Bare rock, a sand dune, a new island formed from volcanic eruptions • Proceeds slowly because the minerals needed by plants are not available—NO SOIL • What makes soil? • Repeated freezing and thawing • Lichens

36. Primary Succession

37. Secondary Succession • Secondary succession • occurs where an existing community has been cleared by a disturbance (like agriculture), but the soil has been left intact • Well-defined stages • Annual grasses (mustards, dandelions) • Perennial grasses and shrubs • Trees like dogwood • Deciduous forest

38. Secondary Succession

39. Succession

40. The Complexity of Succession • Climax community • the final stage of succession. • Populations of plants and animals remain stable and exist in balance with each other and their environment. • Complex picture emerges • Climax communities are not always stable and continue to change • Succession may be “reset” as new disturbances happen