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Community and Ecosystem Ecology

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Community and Ecosystem Ecology Chapter 20 * * * * * * Figure 20.25 A terrarium ecosystem * * Figure 20.32 The carbon cycle Community Ecology Species living in same ... – PowerPoint PPT presentation

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Title: Community and Ecosystem Ecology


1
Community and Ecosystem Ecology
  • Chapter 20

2
Community Ecology
  • Species living in same vicinity
  • Potential interactions will occur
  • Interspecific interactions
  • Interactions between species
  • Classified according to effect on populations
  • Helpful ()
  • Harmful (-)

3
Community Interactions
  • Occurs in a few ways
  • Competition
  • Mutualism
  • Predation
  • Herbivory
  • Parasites and pathogens

4
1. Competition (-/-)
  • Occurs when members of two different species try
    to utilize the same resource
  • Competitive Exclusion Principle
  • No two species can occupy the same ecological
    niche at the same time

5
Competition Between Two Species of Barnacles
6
Competition
  • Competition can lead to resource partitioning
  • decreases competition between the two species
  • Character displacement is often viewed as
    evidence that competition and resource
    partitioning have taken place

7
2. Mutualism (/)
  • Both members of the association benefit

8
3. Predation (/-)
  • Predator
  • Prey
  • 2 ways this regulates population growth
  • A. Predator-Prey Population Dynamics
  • B. Antipredator Defenses

9
3. Predation
  • A. Predator-Prey Population Dynamics
  • Cycling of predator and prey populations
  • Occurs when either predators overkill prey, or
    when prey overuse resources and their numbers
    crash
  • In either case, predator numbers also decrease
    from a decrease in food source

10
Predatory-Prey Cycling of a Lynx and a Snowshoe
Hare
11
Coevolution
  • Evolutionary change in one species results in an
    evolutionary change in the other
  • Organisms in symbiotic associations are
    especially prone to the process of coevolution
  • Also occurs between predators and prey
  • Example Cheetah sprints forward to catch prey,
    and this behavior might be selective for those
    gazelles that jump high in the air

12
3. Predation
  • B. Antipredator Defenses
  • Cryptic coloration
  • Camouflage
  • Warning coloration
  • Association with undesirable consequences

13
3. Predation
  • B. Antipredator Defenses
  • Mimicry
  • One species resembles another species
  • Can help capture food or avoid being preyed upon
  • Batesian Mimicry
  • A prey that is not harmful mimics another
    species that has a successful antipredator
    defense
  • Warning colorations
  • Mullerian mimicry
  • Species that resemble each other all have
    successful defenses

14
Mimicry Among Insects
Mullerian
Batesian
15
Coral snake vs. Milk snake
http//www.youtube.com/watch?vLU8DDYz68kM
16
4. Herbivory (/-)
  • Consumption of plants by an animal
  • Plant must expend energy to regenerate
  • Evolved defenses

17
5. Parasites Pathogens (/-)
  • Parasite
  • Lives on or in a host
  • Endoparasite
  • Ectoparasite
  • Pathogens
  • Disease-causing microorganisms

18
Trophic Structures
  • Feeding relationships among species in a
    community
  • Determines the passage of energy and nutrients
  • Sequence of food transfer is a food chain
  • Unbranched

19
Trophic Structure
  • Autotrophs (producers)
  • Require an energy source and inorganic nutrients
    to produce organic food molecules
  • Manufacture organic nutrients for all organisms
  • Green plants and algae carry on photosynthesis

20
Trophic Structure
  • Heterotrophs (consumers)
  • Need a preformed source of organic nutrients
  • Herbivores
  • Graze directly on plants or algae
  • Carnivores
  • Feed on other animals
  • Omnivores
  • Feed on both plants and animals

21
Trophic Structure
  • Decomposers
  • Heterotrophic bacteria and fungi
  • Break down nonliving organic matter
  • They release inorganic matter to be used by
    producers
  • Scavengers
  • Feed on dead remains

22
Ecosystem Ecology
  • Possesses both abiotic and biotic components
  • Biotic
  • The various populations of organisms that form a
    community
  • Abiotic
  • Includes resources such as sunlight, inorganic
    nutrients, soil, water, temperature and wind
  • Two major processes sustain all ecosystems
  • Energy flow
  • passage of energy through the components of the
    ecosystem
  • Chemical cycling
  • use and reuse of chemical elements within the
    ecosystem

23
Energy flow
Chemical energy
Light energy
Heat energy
Chemical elements
Bacteria, protists, and fungi
24
Energy Flow
  • Biomass
  • Mass of living organic material in ecosystem
  • Ecological Pyramids
  • only about 10 of the energy of one trophic level
    is available to the next trophic level
  • Producers at the base
  • Most available energy
  • Energy is given off in less usable forms as
    producers are eaten by primary consumers, etc.

25
Chemical Cycling
  • Biogeochemical cycles
  • Biotic and abiotic components of the chemical
    cycles in an ecosystem
  • 3 main cycles
  • Carbon cycle
  • Phosphorus cycle
  • Nitrogen cycle

26
CO2 in atmosphere
Burning
Photosynthesis
Cellular respiration
Higher-level consumers
Plants, algae, cyanobacteria
Primary consumers
Wood and fossil fuels
Decomposition
Wastes death
Plant litter death
Decomposers (soil microbes)
Detritus
Figure 20.32
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