What is a Community

1. What is a Community A Community is any assemblage of populations in an area or habitat. Communities: Populations interacting; Population interactions shape communities. Communities are characterized by the interactions among their component populations. In this scene, vultures wait for whatever will remain of a lion’s zebra kill.

2. Yucca community : A web of Interdependence. The mule deer and sap beetle eat yucca flowers, while the ash-throated flycatcher picks off yucca moths. Below-ground, the yucca roots release a soaplike substance that makes scarce water more available for itself and its nitrogen-fixing neighbors.

3. B A Coevolution between the yucca moth and the yucca plant. (A) A female yucca moth (Tegeticula yuccasella) pushing pollen into the stigma tube of the yucca flower while visiting the flower to deposit her eggs. (B) Yucca moth larvae feeding on seeds in the yucca fruit. http://www.britannica.com/ebc/art/print?id=20&articleTypeId=0

4. Strange Community of Aquatic Organisms Discovered in the Deep-Ocean Abyss. In 1977, scientists discovered an entirely new ecosystem based on the heat energy from hydrothermal vents. The living community in this physical setting included yellow vent mussels, crabs (here, looking like ghostly white spiders), large vent clams, and tube worms with red plumes. These plumes take in oxygen, and the worm’s body contains chemoautotrophic bacteria, which produce fixed carbon compounds in this ecosystem.

5. Characteristics of a Community • Diversity • species richness (total number of different species) • Relative Abundance of different species. • Prevalent form of vegetation. • Stability – communities ability to resist change and recover from disturbance. • Trophic structure

6. Biodiversity • Species Richness vs. Relative abundance

7. A population is a group of organisms of the same species, which live in the same place at the same time, and can interbreed with each other. --- Interacting individuals of the same species A community is the organisms of two or more populations of different species occupying the same geographical area, and the interaction between those species. Interacting populations of different species An ecosystem is the interrelationship between organisms and the environment in which they live. A community of speciesinteracting with their physical environment A habitat is a place where an organisms lives. Home or address The niche is a role, function, or position of an organism in a biological community. Job – how it gets its supply of energy and materials Fundamental niche is the potential range of all environmental conditions under which an organism can thrive. Realized niche is the part of the fundamental niche that a species actually occupies in nature.

8. Ecological Niches • The total of a species’ use of biotic and abiotic resources is called the species’ ecological niche • Ecologically similar species can coexist in a community if there are one or more significant differences in their niches • As a result of competition, a species’ fundamental niche may differ from its realized niche • An organism’s niche is its role in the environment • 2 species cannot coexist if their niches are identical • Resource partitioning – differentiation of niches that enable two similar species to coexist in a community

9. The Ecological Niche The sum total of a species use of the biotic and abiotic resources in its environment Fundamental Niche • The theoretical maximum resources that could be used by a population. Realized Niche • The actual resources that are used by a population. Page 712

10. Niche : An Organism’s Role in the Community. (a) The fundamental niche is the full range of conditions under which a given organism can operate. As depicted here, a forest warbler can catch insects in a tree at any height and on branches any distance from the trunk, and it can nest any time between early June and late July. (b) The realized niche is the part of the fundamental niche that the organism actually occupies. The Cape May warbler catches insects only in the outer branches toward the top of the tree, and it nests only in June. The bay-breasted and myrtle warbles feed in different places and nest at different times, and thus occupy separate realized niches within the boundaries of the fundamental niche.

12. Interspecific Interactions

13. Interspecific Interactions • Competition • Predation • Symbiosis • Parasitism • Mutualism • Commensalism

14. Competition between species for limited resources: Interspecific competition – the use of the same resources by 2 different species, --- one or both competitors have a negative effect on the other’s survival or reproduction Competitive exclusion – a situation where one species eliminates another through competition --Two species cannot indefinitely occupy the same ecological niche. The one that is more efficient in taking advantage of available resources will exclude the other. --Two species cannot coexist when they have identical needs of a limited resource. Page 713 - 714

15. Interactions between Organisms Competition results when organisms require the same limited resource. Competitive exclusion The theory that populations of two species competing for a limited resource can not coexist indefinitely in the same habitat. Example: Lemna polyrhiza grew individually faster than L. gibba. When the two were grown together L. polyrhiza was always replaced by L. gibba. L. gibba – airsacs to float over L polyrhiza, cuttingoff the light.

16. Competition between species for limited resources: Competitive exclusion G. F. Gause, Russian biologist, 1934 – designed a laboratory experiment, Competition between Paramecium species for the same resources (bacterial cells) in the same culture.

17. Competition between species for limited resources: Competitive exclusion P. caudatum – large celled sp (lcs) and P. aurelia – small celled sp (scs) -- grew each sp in its own container – population growth reflected the standard S-shaped curve -- grew them in the same container – interspecific competition occurred and the smaller celled sp drove the larger celled sp to extinction Reasons: scs 1 was more resistant to bacterial waste products than lcs 2 reproduced more rapidly than lcs

18. Natural causes of Competitive Exclusion 1. Resource (Exploitation) competition = Occurs when use of a resource by one individual/population/species reduces the availability of that resource to other individuals/populations. (Two sp. exploit and have equal access to identical resources) 2. Interference competition = Competition between two individuals/populations/species in which one physically or chemically excludes the other from a portion of habitat and hence from the resources that could be exploited there. (The use of aggressive behavior to keep competitors from a resources) Page 714

19. How have some species reduced or avoided competition • Resource partitioning - dividing up the scarce resources so that species with similar requirements use them at different times, in different ways, or in different places. • Ex. If lions and leopard live in the same area the lions take the bigger prey while the leopards take the smaller Page 715, and Fig. 35.6

20. A. insolitus usually perches on shady branches. A. ricordii A. insolitus A. distichus perches on fence posts and other sunny surfaces. A. aliniger A. christophei A.distichus A. cybotes A. etheridgei Seven species of Anolis lizards live in close proximity at La Palma in the Dominican Republic.

21. Character Displacement Character displacement is a tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species Ex. Anolis lizards split up the territory and occupy a different niche as their hereditary changes in physical and behavior characteristic. Such change is called character displacement. Character displacement is an example of coevolution, heredity changes in two or more species as a consequence of their interactions within a community. Character displacement brings about a partitioning of resources by competing species.

22. Resource Partitioning

23. Interspecific Interactions • Competition • Predation - page 716 • Symbiosis • Parasitism • Mutualism • Commensalism

24. Predation • Animals eating animals • Animals eating Plants - herbivory • Parasitism - parasite feeding on body fluids of host.

25. Interactions between Organisms Predation refers to interaction where one species, the predator, kills and eats the other, the prey. Some feeding adaptations of predators are claws, teeth, fangs, stingers, and poison Predators that pursue their prey are selected for speed and intelligence. Carnivores store information about the prey’s escape strategies and must make quick choice while in pursuit Predation and parasitism directly benefit one species (the predator or parasite) and directly harm the other (the prey or host).

26. Predator Adaptations • Acute Senses - Smell, Eyesight, Hearing.

27. Interactions between organisms Predation: Predator and Prey Genetic changes in response to natural selection resulting in a grand co-evolution race, with predators evolving more efficient ways to catch prey and prey evolving ways to escape. Predator needs a way to catch its food – pursuit and ambush Predator-Prey and Parasite-Host Coevolution: The relationships between predator and prey, and parasites and hosts, have coevolved over long periods of time.

28. Predation Predation- when an organism captures and feeds on another organism. Predators tend to be larger than their prey, and consume many prey during their lifetimes. Predator- hunter; Prey- hunted

29. Prey and Defense (page 719) Prey species have various forms of protection. They can run, jump, swim or fly. Some have developed keen eyesight or sense of smell that alerts them to the presence of predators Prey display various defensive adaptations Behavioral defenses include hiding, fleeing, self-defense, and alarm calls Animals also have morphological and physiological defense adaptations

30. Plant Defenses Against Herbivores • Chemicals, Crystals, Thorns.

31. Animal Adaptations against Predators • Passive defenses - hiding • Active defenses - running away

32. Insect Camouflage and Mimicry are adaptations Self - Protection: Camouflage and Mimicry Avoiding Predation -- minimize the risk of being preyed upon Camouflage comes from the French word camouflager which means to "blind or veil". Camouflage, called cryptic coloration – an outcome of an organism’s form, patterning, color or behavior that helps it blend with its surroundings and escape detection. An animal that uses camouflage looks like things in its environment. It might look like a leaf, a twig, or a rock. Mimicry – the evolution of similar appearance in two or more species, which often gives one or all protection. Animals that use mimicry use colors and markings to look like another animal.

33. WARNING AND MIMICRY • Predator deterrent evolves • Warning • color of bees & wasps • coral snakes • monarch butterflies • Convergence in warning – Mullerian Mimicry • Copy the warning without the deterrent Batesian Mimicry • moths & flies • king snakes • viceroy butterfly

34. Defensive Mechanisms • Batesian Mimicry - Harmless species evolve characteristics that mimic unpalatable, dangerous or poisonous species • Viceroy and Monarch butterfly • Mullerian Mimicry - Two unpalatable species evolve to look alike • Bees and Wasps • Camouflage • Advertising and warning (coral snake) • Attracting prey, pollinators, mates, etc.

35. Cryptic Coloration(camouflage) Occurrence of shapes, colors, patterns or even behaviors that enable organisms to blend in with their background. One defense strategy avoids confrontation through camouflage.

36. Cryptic Coloration, making a potential prey difficult to spot against its background. Cryptic Katydids: Katydids camouflage to a wide variety of environments. Can you find the katydid in each picture? http://www.thewildones.org/Animals/camo.html

37. The motionless twig caterpillar complete with "buds" and "lenticels" escapes detection by birds (but pays for its cleverness by occasionally having some other insect lay eggs on it by mistake). Walking sticks have adapted to resemble their surroundings. Most of the time, their predators pass them by as they would a real twig. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mimicry.html

38. Phyllium bioculatum Aretaon asperrimus.  This appears to be a moss and lichen mimic, and blends in well, if you don't already know something is there http://www.bugsincyberspace.com/mimicry_and_camouflage.html http://www.bugsincyberspace.com/mimicry_and_camouflage.html

39. Deceptive coloration Another form of adaptive coloration, large fake eye or false head can apparently deceive predators momentarily, allowing the prey to escape. Large eye spots that make them look like scary animals and frighten predators away. Eyespots: Common BuckeyeJunonia coenia Eyespots: Io Moth (Automeris io) http://www.fieldmuseum.org/butterfly/thumb10.htm

40. Sometimes harmless insects look ferocious, frightening their enemies. Hickory horned devil, large caterpillar scares away its enemies by its appearance

41. Aposematic Coloration, Warning colors Animals with effective physical or chemical defense often exhibit bright warning coloration, called aposematic coloration. Poisonous prey species usually evolve brightly colored patterns, enabling the experienced predator to recognize and avoid them.

42. Mimicry is a different type of camouflage. Animals do not try to blend in with their surroundings, but instead mimic a different type of animal. Many nonpoisonous prey species masquerade as poisonous species. Ex. A number of harmless snakes have evolved very similar coloration to highly poisonous snakes. Many types of harmless, stingless flies have evolved a very similar appearance to bees and wasps.

43. Aposematic coloration Monarch butterfly Danaus plexippus Bright warning coloration and mimicry occur in many groups of butterflies. The monarch caterpillar feeds on milkweed, which makes the adult butterfly bitter and poisonous to birds. Birds learn quickly to avoid its bright orange and black pattern.

44. Batesian mimicry • Monarch Butterfly – Toxic model • Viceroy Butterfly – Harmless mimic.

45. Batesian mimicry, a palatable species mimics an unpalatable model. ViceroyLimenitis archippus MonarchDanaus plexippus The viceroy butterfly, on the other hand, is better tasting, but still unpleasant. Because its orange color and black stripes are like the colors of the monarch, birds learn to avoid both at once -- butterflies of both species and the birds benefit! http://www.fieldmuseum.org/butterfly/thumb5.htm

46. Batesian mimicry Many animals that eat spiders find ants distasteful. The ant-mimic spider is more likely to survive because it resembles its two less-edible ant companions.

47. Batesian Mimicry A palatable or harmless species mimics an unpalatable or harmful model. Hawk Moth Mimicry: This moth caterpillar defends itself by mimicing a snake. The back of the hawk moth caterpillar actually looks like a snake head, a frightening visage for most predators the moth would come across.

48. Mullerian Mimicry • Two or more unpalatable species resemble each other

49. Aggressive Mimicry Some carnivores have evolved devices with which they mimic the prey (or potential mate) of other (usually smaller) predators. They use these devices as lures. The angler fish (Antennarius) displays a lure resembling a small fish. The lure is a development of the spine of the first dorsal fin. This species of anglerfish, which was found in the Philippines, is 9.5 cm long. Note its use of camouflage: its texture (and color) closely resemble the sponge- and algae-encrusted rocks found in its habitat. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mimicry.html

50. Chemical warfare The beetle emits an evil-smelling fluid from its abdomen, as a defence mechanism. This fluid rapidly evaporates into a gas, which appears like a minute jet of smoke when in contact with air, and blinds the predator about to attack. ClassificationBombardier beetles in genus Brachinus, family Carabidae, order Coleoptera, class Insecta, phylum Arthropoda. Bombardier beetle http://www.talkorigins.org/faqs/bombardier.html Page 721 http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0063590.html