COMMUNITY-SPECIES-INTERACTION_General Ecology

Community
all the organisms that live together in a place

Community Ecology
study of interactions among all -populations in a common environment

In what ways do populations interact?

Community – all the organisms that live together in one place

Community ecology – study of interactions among all populations in a common environment.

Interspecific interactions – among individuals of the different species.

Intraspecific interactions – among individuals of the same species.

Species Interaction…
-A traditional approach to population interactions has been to consider the direct pair-wise interactions.

1. BIO104 LEC 6 COMMUNITY

2. Community Ecology biosphere ecosystem community population organism

3. Community Ecology Community all the organisms that live together in a place Community Ecology study of interactions among all populations in a common environment Answers the Q: In what ways do populations interact?

4. SPECIES INTERACTION: The HEART of ECOLOGY

5. Definition of terms Community – all the organisms that live together in one place Community ecology – study of interactions among all populations in a common environment. Interspecific interactions – among individuals of the different species. Intraspecific interactions – among individuals of the same species.

6. Species Interaction… A traditional approach to population interactions has been to consider the direct pair wise interactions. Two populations may or may not affect each other; if they do, the influence may be beneficial or adverse.

7. Designations: (-)  detrimental effect (+)  beneficial effect (0)  no effect

8. Types of Population Relationships Interspecific interactions : Competition and Coexistence Predation Mutualism Commensalism How about: Amensalism ? Altruism?

9. Intraspecific Interactions Grasshoppers provide an animal example. Individual grasshoppers deprive their fellow conspecifics of food (exploitation competition ). It is probably a major factor involved in the evolution of plumage patterns in birds. during intraspecific competition, animals will use whatever weapons are available to them and this makes it likely that the nature of the weapons determines the nature and location of patterns.

10. Direct Pairwise Interactions between 2 populations: Competition and Coexistence Predation Mutualism Commensalism ( Amensalism )

11. Competition (-,-) it can be interspecific or intraspecific this takes place when each of two populations affects the other adversely both require the same resource/s that is/ are in short supply.

12. Two Mechanisms of Competition 1.Exploitation competition organisms use up resources directly.  Once used, the resource is no longer available for other species. More common mechanism 2.Interference interaction one organism prevents other organisms from using the resource. can occur, particularly where the resource is " patchy " - only occurring in discrete patches - and thus able to be defended. 

13. Competition… Territorial animals : some individuals actively prevent others from exploiting a given resource. Example: An elephant might be able to prevent other animals from using a water hole, but would be unlikely to be able to chase them away from a river with its long banks.

14. 1.Scramble (resource) competition Organisms compete for a limiting resource Observed in invertebrates No need for individuals to interact directly, as each takes from a common resource Each competitor affects all other competitors by reducing the amount of resource available to others

15. Scramble (resource) competition: 2 types Exploitative -- consumption of the same food item or abiotic resource Preemptive -- taking space on a surface needed for living (rocks for mussels, land for plants, etc.)

16. 2. Contest (interference) competition individuals harm each other by physical force observed in vertebrates

17. What is Competitive Exclusion ? states that two species competing for the same limiting resource in an area cannot coexist. it is rare to find two very closely related species in the same area.  one species or the other will be better at the competition and will displace the other. if they live in the same area, they differ in the way they use the resources often not in apparent way. two species cannot share the same niche. Niche – functional role of an organism in an ecosystem

18. Competitive Exclusion… Example: a series of birds might feed in the same trees for the same insects. However, each species might forage only on a particular part of the tree - such as the top, the bottom, the inner branches, etc. In this way they reduce the competition and are able to co-exist.  nuthatch (works its way UP the trunk) and the brown creeper (forages Down the trunk).

19. Florida's native anole, the Green Anole ( Anolis carolinensis , left) is a direct competitor with the introduced Brown Anole ( Anolis sagrei , right). where the two are found together, the Green Anoles are more common on the vegetation and higher up, while the Brown Anoles tend to occupy the ground and the tree trunks.

20. Competitive Exclusion… One trick that some organisms use to reduce competition within the species is to partition the habitat between the young and the adults. Example: Caterpillars feed on plants while butterflies only sip nectar tadpoles live in the water feeding on algae while the adult frogs are carnivorous

21. Butterflies get nectar from the flower of the plant while caterpillars feed on the plant itself (mostly on leaves).

22. Competition... Lotka - Volterra model 4 results: species 1 extinct, species 2 extinct, species 1 &2 extinct or species 1 & 2 coexist Experiments on competition Gause on Sacccharomyces and Schizosaccharomyces Thomas Park on Tribolium comfusum and Tribolium castaneum

23. Predation (+,-) This occurs when one population affects another adversely but benefits itself from the interaction A biological interaction where a predator (an organism that is hunting) feeds on its prey, the organism that is attacked. the act of predation always results in the death of the prey

24. Predation --- 3 Types: Predator and prey Parasitism Herbivory

25. Predation  Predator & prey a predator kills its prey and consumes part or all of the prey organism some predators kill large prey and chew it prior to eating it, such as a lion, while others may eat their (usually much smaller) prey whole .

26. Predation… Predator & Prey Some predation entails venom which subdues a prey creature before the predator ingests the prey by killing, which the box jellyfish does, or disabling it, found in the behavior of the cone shell. In some cases the venom, as in rattlesnakes and some spiders, contributes to the digestion of the prey item even before the predator begins eating. In other cases, the prey organism may die in the mouth or digestive system of the predator. Baleen whales, for example, eat millions of microscopic plankton at once and being broken down well after entering the whale. A predator serves a role, but they result in the death of the prey.

27. Predation  Parasitism (+,-) is a type of symbiotic relationship between two different organisms where one organism, the parasite, takes from the host, sometimes for a prolonged time essentially identical to predation except that the host is usually not killed outright but is exploited over some period of time. “weak” form of predation parasites don’t actually kill their victims, but they do cause harm.

28. Classification of Parasites (based on their interactions with their hosts and lifecycles) ectoparasites (e.g. some mites) - those that live on its surface. epiparasite - is one that feeds on another parasite. This relationship is also sometimes referred to as hyperparasitism which may be exemplified by a protozoan (the hyperparasite ) living in the digestive tract of a flea living on a dog. endoparasites (e.g. hookworms) - those that live inside the host. can exist in 2 forms: intercellular (inhabiting spaces in the host’s body) intracellular (inhabiting cells in the host’s body)

29. What is a parasitoid? an organism that spends a significant portion of its life history attached to within a single host which it ultimately kills (often consumes). term coined by O.M. Reuter

30. Parasitoid, an example: Tachinid fly (Family Tachinidae )

31. All Tachinid flies have evolved different ways of infecting their hosts: Some stick eggs directly on the host Some deposit eggs on foliage of host food plants to be ingested by the host. Some species lay their eggs their hosts, when hatch, those larvae move towards their host and get into their body through the soft part of the host skin. Females of some other species that attack bugs and adult beetles have piercing ovipositors that insert their eggs into the body of their hosts Some species, instead of laying eggs, they lay live larvae and apply them onto the host using either one of the about methods.

32. Predation  Herbivory is a form of predation in which an organism, known as an herbivore , consumes principally autotrophs such as plants, algae and photosynthesizing bacteria however, it is generally restricted to animals eating plants herbivores form an important link in the food chain as they consume plants in order to receive the carbohydrates produced by a plant from photosynthesis.

33. Mutualism (+,+) interaction between individuals of two different species where individuals derive a fitness benefits, for example, increased survivorship. mostly observed in mutualistic pollination systems. Ex. Male euglossine bees visit flowers for floral fragrance

34. Mutualism… Dispersal systems Ex. Calvaria major in Mauritius (left) cannot propagate unless seeds eaten by dodo (right)

35. Mutualism Protection system Ex. Ants and aphids Aphids secrete honeydew which is being eaten by the ants while ants protect aphids from predators

36. Commensalism (+,0) The norm in a community One population benefits while the other is unaffected Phoresy : association involves passive and more-temporary transport of one organism by the other Ex. Anemones on hermit crab shells

37. A small frog seems to be hiding in the middle of the water lily waiting for its prey to be ambushed.

38. Amensalism (-,0) said to occur when one population is affected adversely by another but the second is unaffected. this is not a type of symbiosis since it does not exhibit an intimate relationship among organisms involved this usually this occurs when one organism exudes a chemical compound as part of its normal metabolism that is detrimental to another organism

39. Amensalism … Allelopathy - the inhibition of growth of a plant due to biomolecules released by another. Examples: Common bread mold, penicillium secrete penicillin (0), a chemical that kills bacteria (-). the black walnut tree ( Juglans nigra ), which secrete juglone , a chemical that harms or kills some species of neighboring plants, from its roots

40. Altruism?

41. ALTRUISM 1.  Loving others as oneself.   2. promotes the survival chances of others at a cost to ones own. 3. Self-sacrifice for the benefit of others –Auguste Comte coined the word  altruis me   Zoology.  Instinctive behavior that is detrimental to the individual but favors the survival or spread of that individual's genes, as by benefiting its relatives.

42. wolves and wild dogs bring meat back to members of the pack that were not present at the kill

43. sacrificing one’s chances of reproducing

44. vampire bats regurgitate blood to those that were not able to hunt Buddy system ( Wilkinson,G.)

45. male Golden orb-weaving spiders self-destruct after mating while still intact to the female

46. The altruistic gene causes an organism to behave in a way which reduces its own fitness but boosts the fitness of its relatives — who have a greater than average chance of carrying the gene themselves.

47. overall effect :increase the number of copies of the altruistic gene found in the next generation, and thus the incidence of the altruistic behavior itself.

48. When thinking about Community Ecology Keep in mind: the Food Pyramid (The Trophic Levels) the Biogeochemical Cycles