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Ecosystems & Living Organisms: Interactions and Niches.

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Presentation on theme: "Ecosystems & Living Organisms: Interactions and Niches."— Presentation transcript:

1 Ecosystems & Living Organisms: Interactions and Niches

2 Biological Communities Lack defined boundaries  orgs never isolated Intrxns. lead to creation of ecological niches- Each org. has a role in an ecosystem.

3 Competitive Exclusion Two species with similar requirements cannot occupy the same niche (Gause’s Law) P. aurelia P. caudatum

4 Logistic Growth



7 Keystone Species Key members of community –Critical elements –NOT always most abundant – ALWAYS most important KEY to conservation efforts

8 What is Predation? Members of a predator species prey on members of a prey species

9 Stephen Colbert: Snakes and Hamsters /index.jhtml?ml_video=58446 videos/58446/january-31-2006/craziest-f--king-thing-i-ve- ever-heard---snake-and-hamster

10 Structural Natural Weapons: Fangs, claws Flexible bodies and Larger Size Predator Strategies

11 Sharp Talons!!

12 Ambush Techniques: Stalk a victim, Gape & Suck (fish), Keen eyesight, Venom Predator Strategies

13 Prey Strategies Defense Techniques: Inflate, Flee, Fight Back, Stab, Poison

14 Structural advantages: Hard Body, Thorns/Spines, Break away body parts, Nat. Weapons Prey Strategies


16 Predation Feedback Systems Positive feedback (outcome is +) for predator gets to eat prey, can reproduce… Negative feedback (outcome is -) = prey population falls, no food, decrease in predator population

17 Mimicry Batesian mimicry: a harmless species looks like a harmful species Mullerian mimicry: 2 harmful species look like each other Scarlet King Snake Coral Snake Cuckoo Bee Yellow jacket

18 Interactions Among Organisms Symbiosis: relationship b/t 2 species Mutualism (+,+) Commensalism (+,0) Parasitism (+,-)

19 Mutualism Both Species Benefit Rhinos and oxpeckers



22 Mycorrhizae Symbiotic fungus found on plant roots Aids in water retention, mineral uptake (nitrates) W/out MWith M

23 Commensalism One member is helped, the other neither benefits or is harmed Cows and Cattle Egrets

24 Parasiti sm + and - relationship parasite benefits, host loses parasite usually smaller than host Leech Bite, Thailand Lamprey

25 Endoparasites Parasites that live within the body of the host! Ex. Tapeworm…

26 Ectoparasites Parasites that feed on the external surface of the host. Ex: ticks

27 Intraspecific Competition Between SAME species

28 Interspecific Competition Competition between DIFFERENT species

29 Intra or Interspecific Competition?? 3bJq8 3bJq8

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