Community Ecology - PowerPoint PPT Presentation


Title: Community Ecology


1
Community Ecology
Chapter 54
2
Community
  • Def. group of populations (different species)
    that live close enough to interact
  • Interspecific Interactions - How the populations
    in a community interact with the environment
    each other
  • Some of the key relationships in the life of an
    organism are with OTHER species
  • IF the key relationship was with members of the
    same species, then the relationships would be
    called intraspecific interactions

3
Community Interactions
  • Also called interspecific interactions
  • 3 Basic Categories
  • 1. Competition
  • 2. Predation
  • 3. Symbioses
  • a) Parasitism
  • b) Commensalism
  • c) Mutualism

4
Competition
  • Competition harms both species
  • Called a / -- interaction
  • Competition is predicated on 2 concepts
  • Competitive Exclusion Principle
  • When 2 species compete, 1 must lose will be
    eliminated from the environment
  • 1 species will always have an advantage
  • Ecological niche
  • All of the biotic abiotic resources that a
    species uses in its environment

5
Competitive Exclusion Principle
  • Gause studied paramecium
  • Discovered competitive exclusion principle
  • Two (2) species cannot coexist in a community, if
    they occupy the same niche
  • For example, 2 paramecium species were studied,
    and one was more fit than the other
  • The result was that the less fit species was
    driven to extinction
  • Competition between 2 species occupying the same
    niche can lead to 2 other options besides
    extinction, both involve some form of evolution

6
Niche
  • When species compete for resources, it is
    important to understand their niche
  • Niche sum total of a species use of the biotic
    abiotic resources in an environment
  • Think of it as the species place in the
    ecosystem
  • The roles (jobs) it occupies in an ecosystem
  • For example, a lion occupies the niche of
    predating (thinning?) herbivore populations
  • Another HIV occupies the niche

7
2 Results of Competition
  • While extinction is possible, usually we get one
    of 2 situations due to competition for the same
    resource
  • 1. Resource Partitioning One species evolves to
    exploit different resources
  • Different niche, but pretty close to the other
    species
  • 2. Character Displacement divergence in body
    structure (via evolution) enabling access to
    different resources
  • Darwins Finches beaks

8
Resource Partitioning
-- Different Anoles (Lizards) predate the same
populations, but in different parts of a wooded
environment
9
Character Displacement
-- Finches evolved different beak depths, so they
are able to eat different types of seeds
10
Predation
  • 2nd type of interspecific interaction
  • Predatory Defenses include
  • Cryptic coloration
  • Aposematic (warning) coloration
  • Batesian mimicry
  • Mullerian mimicry
  • Herbivorous defenses

11
Anti-Predation Defenses
  • Plants
  • Physical defense mechanisms - spines/thorns
  • Chemicals/Poisons strychnine, mescaline,
    morphine, nicotine
  • Animals
  • Active defenses hiding, fleeing or defending
    themselves
  • Passive defenses Cryptic coloration or
    camouflage
  • Make it difficult for prey to be located

12
Predation Defense Mechanism
13
Predation Defense Mechanism
  • Aposematic Coloration bright coloration
  • Typically orange or red
  • Typically reserved for poisonous animals
  • Visible warning to predator to stay away
  • Batesian Mimicry
  • Copycat coloration
  • Harmless animal copies
  • the coloration of an animal
  • that is poisonous

14
Mullerian Mimicry
  • 2 or more poisonous species resemble each other
    and gain an advantage from their combined numbers
  • Predators quickly learn to avoid anything
    resembling this coloration

15
Symbioses
  • 1. Parasitism (/-)
  • -- Similar to predation (just takes longer)
  • -- Many ecologists link parasitism predation
  • 2. Commensalism (/0)
  • -- Barnacles on a whale underbelly
  • 3. Mutualism (/)
  • -- Bacteria inhabit GI tract produce vitamins

16
Food Chain
  • Def pathway by which food (energy) is
    transferred from one trophic (feeding) level to
    another
  • Energy moves from producers ? herbivores ?
    carnivores
  • 10 of energy at any trophic level is transferred
    to the next level
  • Because of this minority energy transfer, food
    chains are limited to 4 or 5 trophic levels

17
Trophic (food) Pyramid
What of energy is transferred to the next
trophic level?
18
Trophic Pyramid
  • Primary Producers
  • Green Plants
  • Convert light energy to chemical bond energy
  • Greatest biomass
  • Diatoms phytoplankton
  • Primary Consumer
  • Herbivores
  • Eats producers
  • Grasshoppers

19
Trophic Pyramid (Page 2)
  • Secondary Consumers
  • Carnivores
  • Eat primary consumers
  • Frogs small fish
  • Tertiary Consumers
  • Carnivores
  • Eat secondary consumers
  • Top of the food chain
  • Least biomass
  • Hawk, salmon, human

20
Food Chain (Page 2)
  • When considered in interrelation are called food
    webs
  • An animal can occupy one trophic level in one
    food chain, but a different trophic level in a
    different food chain
  • Example, a human is a primary consumer when
    eating vegetables, but a tertiary consumer when
    eating a salmon
  • Decomposers are usually not featured in trophic
    pyramids
  • BUT they are integral to food chains the circle
    of life
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Community Ecology

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Title: Community Ecology


1
Community Ecology
Chapter 54
2
Community
  • Def. group of populations (different species)
    that live close enough to interact
  • Interspecific Interactions - How the populations
    in a community interact with the environment
    each other
  • Some of the key relationships in the life of an
    organism are with OTHER species
  • IF the key relationship was with members of the
    same species, then the relationships would be
    called intraspecific interactions

3
Community Interactions
  • Also called interspecific interactions
  • 3 Basic Categories
  • 1. Competition
  • 2. Predation
  • 3. Symbioses
  • a) Parasitism
  • b) Commensalism
  • c) Mutualism

4
Competition
  • Competition harms both species
  • Called a / -- interaction
  • Competition is predicated on 2 concepts
  • Competitive Exclusion Principle
  • When 2 species compete, 1 must lose will be
    eliminated from the environment
  • 1 species will always have an advantage
  • Ecological niche
  • All of the biotic abiotic resources that a
    species uses in its environment

5
Competitive Exclusion Principle
  • Gause studied paramecium
  • Discovered competitive exclusion principle
  • Two (2) species cannot coexist in a community, if
    they occupy the same niche
  • For example, 2 paramecium species were studied,
    and one was more fit than the other
  • The result was that the less fit species was
    driven to extinction
  • Competition between 2 species occupying the same
    niche can lead to 2 other options besides
    extinction, both involve some form of evolution

6
Niche
  • When species compete for resources, it is
    important to understand their niche
  • Niche sum total of a species use of the biotic
    abiotic resources in an environment
  • Think of it as the species place in the
    ecosystem
  • The roles (jobs) it occupies in an ecosystem
  • For example, a lion occupies the niche of
    predating (thinning?) herbivore populations
  • Another HIV occupies the niche

7
2 Results of Competition
  • While extinction is possible, usually we get one
    of 2 situations due to competition for the same
    resource
  • 1. Resource Partitioning One species evolves to
    exploit different resources
  • Different niche, but pretty close to the other
    species
  • 2. Character Displacement divergence in body
    structure (via evolution) enabling access to
    different resources
  • Darwins Finches beaks

8
Resource Partitioning
-- Different Anoles (Lizards) predate the same
populations, but in different parts of a wooded
environment
9
Character Displacement
-- Finches evolved different beak depths, so they
are able to eat different types of seeds
10
Predation
  • 2nd type of interspecific interaction
  • Predatory Defenses include
  • Cryptic coloration
  • Aposematic (warning) coloration
  • Batesian mimicry
  • Mullerian mimicry
  • Herbivorous defenses

11
Anti-Predation Defenses
  • Plants
  • Physical defense mechanisms - spines/thorns
  • Chemicals/Poisons strychnine, mescaline,
    morphine, nicotine
  • Animals
  • Active defenses hiding, fleeing or defending
    themselves
  • Passive defenses Cryptic coloration or
    camouflage
  • Make it difficult for prey to be located

12
Predation Defense Mechanism
13
Predation Defense Mechanism
  • Aposematic Coloration bright coloration
  • Typically orange or red
  • Typically reserved for poisonous animals
  • Visible warning to predator to stay away
  • Batesian Mimicry
  • Copycat coloration
  • Harmless animal copies
  • the coloration of an animal
  • that is poisonous

14
Mullerian Mimicry
  • 2 or more poisonous species resemble each other
    and gain an advantage from their combined numbers
  • Predators quickly learn to avoid anything
    resembling this coloration

15
Symbioses
  • 1. Parasitism (/-)
  • -- Similar to predation (just takes longer)
  • -- Many ecologists link parasitism predation
  • 2. Commensalism (/0)
  • -- Barnacles on a whale underbelly
  • 3. Mutualism (/)
  • -- Bacteria inhabit GI tract produce vitamins

16
Food Chain
  • Def pathway by which food (energy) is
    transferred from one trophic (feeding) level to
    another
  • Energy moves from producers ? herbivores ?
    carnivores
  • 10 of energy at any trophic level is transferred
    to the next level
  • Because of this minority energy transfer, food
    chains are limited to 4 or 5 trophic levels

17
Trophic (food) Pyramid
What of energy is transferred to the next
trophic level?
18
Trophic Pyramid
  • Primary Producers
  • Green Plants
  • Convert light energy to chemical bond energy
  • Greatest biomass
  • Diatoms phytoplankton
  • Primary Consumer
  • Herbivores
  • Eats producers
  • Grasshoppers

19
Trophic Pyramid (Page 2)
  • Secondary Consumers
  • Carnivores
  • Eat primary consumers
  • Frogs small fish
  • Tertiary Consumers
  • Carnivores
  • Eat secondary consumers
  • Top of the food chain
  • Least biomass
  • Hawk, salmon, human

20
Food Chain (Page 2)
  • When considered in interrelation are called food
    webs
  • An animal can occupy one trophic level in one
    food chain, but a different trophic level in a
    different food chain
  • Example, a human is a primary consumer when
    eating vegetables, but a tertiary consumer when
    eating a salmon
  • Decomposers are usually not featured in trophic
    pyramids
  • BUT they are integral to food chains the circle
    of life
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