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EVOLUTION and ECOLOGY
BIODIVERSITY
Climate zones determine communities
Figure 5-2
Terrestrial biomes
Figure 5-9
Ecological niche
 An organism’s role in its community
 Includes
 what it needs to survive
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Nutrients
Light
Space (habitat)
Oxygen or carbon dioxide
Inorganic compounds
 How it interacts with other species
 The more available niches there are to fill, the
greater the amount of organisms
Niche diversification in
African Rift Lake Cichlids
Model of Cichlid Fish
Diversification
Other examples of ecology
influencing evolution
 Coevolution: two species evolve in response to each
other over time
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Pollinators and flowering plants
Hosts and parasites
Predators and prey
Symbioses
Competition
Hammer orchid
Predation drives evolution of
both predators and prey
 Predators adaptations
 Locate, sneak up on & subdue prey
 Prey adaptations
 elude & defend
horns, speed, coloration
spines, thorns, toxins
Symbiotic interactions
 parasitism (-/+)
 mutualism (+/+)
 lichens (algae & fungus)
 commensalism (+/0)
 barnacles attached
to whale
Competition can affect niches
High tide
Species 1
Low tide
Chthamalus sp.
Species 2
Fundamental Realized
niches
niches
Semibalanus sp.
Ecosystems
Two Necessities for Survival:
Energy Flow and Matter Recycling
Producers: Basic Source of All Food
 Most producers (autotrophs) capture sunlight to
produce carbohydrates by photosynthesis:
Consumers: Eating and
Recycling to Survive
 Consumers get their food by eating or
breaking down all or parts of other organisms
or their remains.
 Herbivores (primary consumers)
 Carnivores
 Omnivores
Respiration: Getting Energy for Survival
 Organisms break down carbohydrates and other
organic compounds in their cells to obtain the
energy for internal reactions.
 This is done through aerobic respiration or
anaerobic respiration.
Decomposers and Detrivores
Energy Flow
 Energy flows through an ecosystem
 Route of energy flow is determined by an
ecosystem’s trophic structure.
 Trophic interactions move energy through an
ecosystem
Simple example:
Humans can impact
natural food webs
 Chemical pollutants
 Invasive species
 Overhunting
~2 months
Energy Flow in an Ecosystem: Losing
Useful Energy in Food Chains and Webs
MATTER CYCLING IN
ECOSYSTEMS
 All organisms are made up of organic molecules
 Carbohydrates
 Proteins
 Lipids
 Nucleic acids
 Essential nutrients are those that are required to make the
organic molecules
 C, H, N, O, P, S
 Organic matter cycles within ecosystems (biogeochemical
cycles)
 Both autotrophs and decomposers play vital roles
Carbon Cycle:
The Nitrogen Cycle:
Bacteria in Action
Phosphorus cycle