Ch 17 Ecosystems

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Ch 17 Ecosystems Interactions
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Ecologists study how ecosystems work

• Nutrient Recycling Abiotic Factors
• 2. Biodiversity
• 3. Food Webs
• 4. Succession
• 5. Energy Pyramids
• 6. Interactions

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What is an Ecosystem?
- living (biotic) nonliving parts (abiotic)
that are interdependent and that interact with
each other

• Biotic
• Plants
• Bacteria
• Animals
• Fungus
• Protists
• All organisms

• Abiotic
• Cycles
• Water
• Carbon
• Nitrogen
• Phosphorus
• Climate
• Soil topography
• etc.

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Ecologists Study Biodiversity
Biodiversity is the variety of different species
in an ecosystem. A healthy, stable ecosystem
has a lot of biodiversity.
Spotted Owl
A frog enjoys a soft pad of moss in the sunlight.
Deer
Chipmunk
Dragon Flies
Ferns
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Ecologists study Food Chains and Food Webs
Food Chain the direct transfer of energy from
one organism to the next
Food Web the complex interaction of any food
chains in a community
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Succession is community wide evolution The slow
replacement of one ecological community by
another. It takes at least 200 years of
succession before a stable, diverse old growth
forest is established.
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Ecologists study energy pyramids
10 Kcal
Energy Pyramids show the flow of energy
through an ecosystem
100 Kcal
1000 Kcal
10,000 Kcal
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Why is it important to study how Ecosystems
Work?
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Like the coniferous forests in the Pacific
Northwest, ecosystems all over the world are
being endangered because of human interaction
with the environment. By studying how
ecosystems work we are better able understand the
the importance of healthy ecosystems and the
effects of habitat destruction.
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Interactions

• Coevolution

• Predation

• Symbiosis

• Competition

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Coevolution

• Back and forth evolutionary adjustment

• Species work together

• Takes a long time

• Caused by natural selection

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How do predators and prey coevolve?

• Prey escape, avoid or fight off predators

• Plants use thorns, spines and prickles

• Secondary compounds

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Symbiotic Relationships
One or more species live together

• Both organisms benefit

• One organism benefits and other is harmed

• One organism benefits and other is unaffected

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Predation

• One organism feeds on another

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Parasitism

• Organism feeds on their prey

• Lives in or on their prey

• Host used for food and place to live

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Commensalism

• One species benefits

• No harm or benefit

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Mutualism

• Both participating species benefit.

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Competition

• Using the same resources
• Could be between same or different species

• Resources can be water, light, food, shelter,
  mates

• Resources must be in short supply

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Niche

• How an organism lives

• Functional role in ecosystem

• Not just a place to live

• Pattern of living

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Fundamental vs Realized Niche

• Where the organism
• CAN live
• Larger area

• Where the organism
• DOES live
• Smaller area

Reduces competion