Chapter 37: ecosystems and communities. Hippos Hippos (herbivores, hairless) barbels, snails, and...
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Transcript of Chapter 37: ecosystems and communities. Hippos Hippos (herbivores, hairless) barbels, snails, and...
Chapter 37: ecosystems and communities
Hippos
• Hippos (herbivores, hairless)barbels, snails, and shovel-nosed gobis eat the dung crocodiles eat the fish and snails
• Microorganisms also feed on the dung and get nutrients which then go to the trees
Competition
• -/-• Ecological niche: biotic
+ abiotic resources in the environment
• Occurs when 2 species are present and fight for resources
• Decreases carrying capacity
Mutualism
• +/+• Examples: Coral reef
and photosynthetic dinoflagellates
Predators
• +/-• Benefits predator, hurts
prey• Prey uses camoulflage
Herbivory
• +/-• As plants are eaten it
must expend E to replace them
• Defenses: thorns, spines, chemical toxins
• Coevolution: Heliconius and passion flower vine
Parasites
• +/-• Example: aphids and
plants
A food web
Species Diversity
• 2 components– Species richness – Relative abundance
– Species diversity often has consequences for the species living in that community
Keystone species
• A species whose impact on the community has a large impact on its community
• Occupies a niche that holds the community in place
Ecological succession• Disturbances: events that damage biological communities,
remove organisms from them and alter the availability of resources
• Ecological succession: the disturbed area may be colonized by a variety of species which are gradually replaced by a succession of other species
• Primary succession: when ecological succession begins in a virtually lifeless area with no soil (ex: new volcanic islands)
• Secondary succession: where a disturbance has destroyed an existing community but left the soil intact (ex: floods)
Ecological succession
Primary succession Secondary succession
Carbon cycle
Phosphorous Cycle
Nitrogen Cycle