Ecosystems and Communities Chapter 4. What shapes an ecosystem? Biotic and Abiotic Factors Biotic...
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Transcript of Ecosystems and Communities Chapter 4. What shapes an ecosystem? Biotic and Abiotic Factors Biotic...
Ecosystems and Communities
Chapter 4
What shapes an ecosystem?
Biotic and Abiotic Factors Biotic Factors living things that affect an organism
–biotic factors affecting bullfrog: plants it eats, birds that might eat it, other species that compete for food or space
What shapes an ecosystem?
Abiotic Factors physical, or nonliving factors that affect organisms
–bullfrog affected by availability of water and temperature of air
Habitat includes both biotic and abiotic factors
Biotic and Abiotic Factors
Biotic Factors
ECOSYSTEM
Abiotic Factors
Niche
An organism’s niche includes: Place in food web Range of temperatures organism needs to
survive Type of food it eats How it obtains food Other species that use it as food Physical conditions necessary for survival When and how it reproduces
Niche
Two species cannot share the same niche in the same habitat.
Different species can occupy similar niches. Ex - three species of warblers live in the
same spruce trees but feed at different elevations and in different part of the trees
Warbler Niches
Bay-Breasted WarblerFeeds in the middlepart of the tree
Cape May WarblerFeeds at the tips of branchesnear the top of the tree
Spruce tree
Community Interactions
Competition same or different species attempt to use an ecological resource in the same place at the same timeresource = necessity of life (water,
nutrients, light, food, space)
Community Interactions Competitive Exclusion Principle - no two
species can occupy the same niche in the same habitat at the same timeDirect competition in nature often
results in winner and loser – losing organism fails to survive
Community Interactions Predation - one organism captures and feeds
on another organism Predator – the one killing and eating Prey – the food Studies show that predation can actually
help maintain diversity. Gray wolves were killed out in many parts of North America. What happened to deer and herbivore populations? What happened to many plant species in North American ecosystems?
Community InteractionsMimicry – a harmless species resembles a poisonous or
distasteful species.
Example: Batesian mimicry – a palatable or harmless species mimics the an unpalatable or harmful model.
Community Interactions Müllerian mimicry - two or more unpalatable
species resemble each other.
Community Interactions Camouflage or cryptic coloration – a passive defense
that makes potential prey difficult to spot against its background.
Aposematic coloration – warning coloration; seen in animals with effective chemical defenses.
Symbiosis When two species live close together. Three types:
Parasitism – one is harmed (host), one benefits (parasite)
Mutualism – both benefit Commensalism – one is neutral, one
benefits
Parasitism examples:
Above: Fleas, ticks, mosquitos and tapeworms are parasites too!
Right: Wheat rust is a parasitic fungus
Mutualism examples:Below: the Oxpecker and the zebra - the oxpecker eats ticks and flys away with a warning scream when danger is near. So the oxpecker gets food and the zebra stays safe and doesn’t have ticks.
Above: the butterfly and the flowers – The butterfly gets the nectar (food) and the flowers get pollinated.
Commensalism examples:
Below: Barnacles on whales – they don’t effect the whale but the barnacles are sessile (the don’t move on their own) and they need to travel through water to get their food.
Above: Sea anemones and clownfish – the sea anemones have nematocysts that sting most organisms but the clownfish is not affected by the stings so the clownfish hide in the anemone so predators can’t get to them.
Ecological Succession
Ecosystem constantly changing due to natural and human disturbancesolder organisms die out and new
organisms move in, causing further changes in the community
Ecological Succession Primary succession – occurs in areas
where no life exists Ex – new rock created by volcano, rock
exposed when glaciers melt
Pioneer species – first to populate new landUsually lichens (algae and fungus) that can break up rock to begin soil formation
Succession changes the composition of species found in a community at a specific time by removing some of them or changing the resources available
Ecological Succession Secondary Succession – occurs when
community is destroyed or altered but soil is still there.
Ex – Fire and clear cutting regrows to mature, stable community called climax community.
Forest Fire Regrowth