chapter 53 community ecology
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Chapter 53 Community Ecology. Community Ecology. The study of the interactions between the species in an area. Succession-good link for review . http://www.restoringearth.co.uk/education/science/geography/ecology/succession/succession.shtm. chameleons. - PowerPoint PPT PresentationTRANSCRIPT
Community Ecology The study of the interactions
between the species in an area.
Succession-good link for review
http://www.restoringearth.co.uk/education/science/geography/ecology/succession/succession.shtm
chameleons Almost half of the world’s
chameleon species live on the island of Madagascar.
Go to pbs. org
Type in chameleons and find out why they really change color!
Community Hypothesis
1. Individualistic2. Interactive
Individualistic Hypothesis
H.A. Gleason Community as a chance
assemblage of species because of similar abiotic requirements.
Interactive Hypothesis F.E. Clements Community as a linked
assemblage of species that function as an integrated whole.
Predictions Individualistic - fuzzy borders Interactive - sharp borders Robert Whittaker – tested the
two ideas against each other.
Results If abiotic factors form a
continuum, then borders are fuzzy.
Individualistic Hypothesis is correct.
Comment Abiotic factors may form
sharp borders. Ex: soil types Result – the Community may
look very much like the Interactive Hypothesis.
Interspecific Interactions
Interaction between species. May be positive, negative, or neutral. Ex:
1. Coevolution2. Predation3. Mimicry4. Competition5. Symbiosis
Coevolution When two
species have reciprocal evolution to each other.
Ex: Flowers and
their pollinators.
Predation (+/-) Predator and
prey relationships.
Ex – Lynx and Hares
Predation Often results in interesting
defenses or adaptations. Ex:
Plant defenses Cryptic coloration Aposematic coloration
Cryptic Coloration A passive defense where the
prey is camouflaged against its environment.
Aposematic Coloration The use of
conspicuous colors in toxic or unpalatable organisms to warn off predators.
poison arrow frogs
Homework Reading – Chapters 53, 55 Chapter 52 - today Chapter 52 – Fri. 4/25 Aquatic Productivity – wait until
data is posted
Mimicry Defense mechanism where the
mimic has a resemblance to another species, the model.
Types: Batesian Mullerian
Batesian Mimicry Palatable species mimics an
unpalatable model.Hawk moth larva Snake
Mullerian Mimicry Two unpalatable species
resemble each other.
Cuckoo Bee Yellow Jacket
Competition When two species rely on the
same limiting resource. Intraspecific competition
usually more severe than Interspecific competition.
Why?
Competitive Exclusion Principle
Predicts that two species with the same requirement can not co-exist in the same community.
One species will survive and the second will go extinct.
Ecological Niche The n-hyperspace of requirements
for a species. How a species “fits into” an
ecosystem. Species can not have niche
overlap, the Competitive Exclusion Principle
Niche Types
1. Fundamental - what a species is theoretically capable of using.
2. Realized - what a species can actually use.
Resource Partitioning A way that species avoid
niche overlap by splitting up the available resources.
Ex: Anolis lizards
A. distichus A. insolitus
Symbiosis When two different species
live together in direct contact. Types:
1. Parasitism2. Commensalism3. Mutualism
Parasitism (+/-) Parasite harms the host. Parasites may be external or
internal. Well adapted parasites don't
kill the host.
Parasitic behavior: A female Nasonia vitripennis laying a clutch of eggs into
the pupa of a blowfly (Phormia regina)
Commensalism (+/o) One partner
benefits while the other is unchanged.
Ex. – Cattle and Egrets
Mutualism (+/+) Both partners
benefit from the interaction.
Ex: Pollinators and flowers
Acacia Tree and Ants
Succession Changes in
species composition over time.
Succession Stages Sere: unstable stage usually
replaced by another community.
Climax: stable stage, self-reproducing.
Succession Types
1. Primary2. Secondary
Primary Succession Building a community from a
lifeless area. Ex: volcanic islands
glaciated areas road cuts
Comment The first example of primary
succession was worked out on the Indiana Dunes.
Stages: Open Beach Beach Grasses Conifers (Junipers and Pines) Oaks Beech-Maple forest (Climax)
Secondary Succession Where a community has been
disturbed and the soil is mostly intact.
Ex: Cutting down a forest Blow-outs on the Dunes
Causes of Succession
1. Autogenic Factors2. Allogenic Factors
Autogenic Factors Changes introduced by the
organisms themselves. Ex: toxins
acids
Allogenic Factors Outside
disturbances Ex: Fire
Floods
Prairie Restoration Project Upland, IN
Biogeography Study of the past and present
distributions of individual species and communities.
Range Limitations
1. Lack of dispersion.2. Failure to survive in new
areas.3. Retraction from former
range area.
Proof Fossil Evidence Pollen Studies Transplant Experiments
Islands Special cases in
Biogeography. Must be colonized from other
areas.
Island Species Factors Island size. Distance from mainland.
Island Size Small islands hold few
species. Why? Fewer niches available for
species to occupy.
Distance from Mainland Closer islands have more
species. Why? Easier for colonization.
Comment Islands tend to have high
numbers of Endemic species Why? Adaptive Radiation and
Evolution of new species.
Summary Know the two hypothesis of
community structure. Know the various types of
interspecific interactions. Know the Competitive
Exclusion Principle and Niche Concept.
Summary Know some examples and
causes of succession. Know how island
communities are shaped.