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Lecture 5.4 ( ch 6) Competition, Symbiosis, Keystone Species. Ecological Niche. Explain this term. Limiting Resources. Any environmental resource that, because it is scarce or at unfavorable levels, restricts the ecological niche of an organism. Explain the Difference. Fundamental niche
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Lecture 5.4 (ch 6) Competition, Symbiosis, Keystone Species
Ecological Niche • Explain this term
Limiting Resources • Any environmental resource that, because it is scarce or at unfavorable levels, restricts the ecological niche of an organism
Explain the Difference • Fundamental niche • Realized niche
Ecological Niche • Green Anole and Brown Anole • Fundamental niches of 2 lizards initially overlapped • Brown anole eventually out-competed the green anole- reduced the green anole’s realized niche
Species Distribution • Related to THREE things: • Fundamental Niche abiotic conditions that it can tolerate • Ability to disperse to a new area • Interactions with other species (symbiosis)
Competition • Interaction among organisms that vie for the same resource in an ecosystem • Intraspecific -v- Interspecific Competition
Gause’s Law of Competitive Exclusion • If two similar species occupy similar niches, one will outcompete the other. • One species excludes another from a portion of the same niche as a result of competition for resources 8
Resource Partitioning (fig 6.16) • Temporal Resource Partitioning (Wolves/Coyotes) • Spatial Resource Partitioning (plants/birds) • Morphological Resource Partitioning (Darwin’s Finches)
Interactions Among Organisms • Symbiosis • An intimate relationship between members of 2 or more species • Participants may be benefited, harmed or unaffected by the relationship • Results of co-evolution Types: Predation, Mutualism, Commensalism
Predation • Predation- the use of one species as a resource by another species. • True predators • Herbivores • Parasites • Parasitoids
Predation True Predators • The consumption of one species by another • Many predator-prey interactions • Most common is pursuit and ambush
PredationParasites • Symbiotic relationship in which one species is benefited and the other is harmed • Parasites rarely kill their hosts • Ex: Varroa mites and honeybees
PredationParasites • Endoparasites –v- ectoparasite Another example: Misletoe
Video: Parasitoids • Catfish & Ciclids in Lake Victoria Africa
Plant Defenses Against Predation • Plants cannot flee predators • Adaptations • Spikes, thorns, leathery leaves, thick wax • Protective chemicals that are poisonous or unpalatable
Animal Defenses Against Predation • Fleeing or running • Mechanical defenses • Living in groups • Camouflage • Chemical defenses • Mimicry
Commensalism (+ 0) • Ex: epiphytes and tropical trees • Mosses • Cattle Egret & Livestock
Mutualism (+ +) Ants & Accacia Trees
Mutualism (+ +) • Plants & Pollinators • Coral/zooxanthellae • Lichens • Micorrhizae
Keystone Species • Elephants (Video: Acacia Trees-v-Savannas) • Pikas(Video) • Sea Stars • Sea Otters • Kangaroo Rat
Ecosystem Engineers • Beavers • Grizzly Bears