Download community ecology - Fall River Public Schools

COMMUNITY ECOLOGY
Honors Biology
OBJECTIVES
• Describe and give examples for all species
interactions and arrange in a graphic organizer
• Contrast species richness and diversity
• Describe stages of succession
• Community are species interacting in a given
area
SPECIES INTERACTIONS
• Symbioses:
– Close interactions among species
– Five types
•
•
•
•
•
Predation
Parasitism
Competition
Mutualism
Commensalism
PREDATION
• Predator captures, kills and consumes prey
• Natural Selection:
– Predators: find, capture and consume prey
– Prey: avoid being captured
• Flee
• Hide and camouflage
PREDATION
• Mimicry:
– Harmless species resembles poisonous species
– Poisonous resembles other poisonous
• Herbivores eat plants
– Plant adaptations:
• Physical: sharp thorns, spines, tough leaves
• Chemical defenses: bad tasting, irritating, poisonous
(secondary compounds)
PARASITISM
• Species interaction where one species is
harmed and the other benefits
• No killing and consuming
• Parasite and host
• Ectoparasite: live on body; ticks
• Endoparasite: live in body: tapeworm
PARASITISM
• Evolution:
– Defense mechanisms: skin, chemical protection in
openings
– Parasites: tapeworms absorb through skin
COMPETITION
• Fundamental niche overlap – use of same
resource
• Competitive exclusion: one species is
eliminated from community because of
competition for resources
COMPETITION
• Character Displacement:
– Differences between competitors
– Beaks on finches
• Resource Partitioning
– Each use part of resources
– Time partitioning
MUTUALISM
• Both species benefit
• Ants in the acacia plant
• Flowers and pollinators
COMMENSALISM
• One species benefits and other is not affected
• May not be any true cases
• Egrets feeding on buffalo
SPECIES RICHNESS AND DIVERSITY
• Species Richness
– Number of species in a community
– Closer to equator: greater richness
– Larger areas have more species: species area
effect
• Species Diversity
– Relative abundance of each species in a
community
SUCCESSION
• Disturbances can trigger a sequence of
changes in the composition of a community
• New species come right in  new species
• Gradual sequential regrowth of species in an
area
• Pioneer Species: small, fast growing, fast
reproducing
PRIMARY SUCCESSION
• Development where life was never supported
• Slowly – minerals needed for growth are
unavailable
SECONDARY SUCCESSION
• Replacement of species in area following
disruption from natural disaster or human
activity
• Cleared by agriculture or natural disaster
• Soil intact
• About 100 years for original return; stages
• Annual Grasses  Perennial Grasses  shrubs
 trees
COMPLEXITY
• Succession until climax community
• Organisms alter environment to make it
favorable for next organisms