Ecosystems and Living Organisms

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Ecosystems and Living Organisms
Chapter 4
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Evolution

• Genetic changes in a population through time.
• Occurs through natural selection

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Evolution of the 6 Kingdoms of living organisms
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The origin of species Evolution in Darwins
Finches in the Galapagos Islands
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Biological Communities

• Rotting Log Community

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Biological Communities

• Succession
• How Communities Change over Time
• Primary succession

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Biological Communities

• Succession How Communities Change over Time
• Primary succession

Rocks
Lichens
Mosses
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Biological Communities

• Succession How Communities Change over Time
• Primary succession

Rocks
Lichens
Mosses
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Biological Communities

• Secondary Succession

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Interactions Among Organisms

• Symbiosis
• one species living in or on another species
• results from coevolution

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Symbiosis Three types

• Mutualism Two species living together in a
  relationship in which both benefit from the
  association.
• Commensalism two organisms are associated in a
  relationship in which one benefits from the
  relationship and the other is not affected
• Parasitism The close association of two or more
  dissimilar organisms where the association is
  harmful to at least one.

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No mutualism mo root fungus
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Mutualism both mycorrhizae and plant benefit
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Commensalism epiphytic plants
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Parasitic kites in an insects trachae
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Interactions Among Organisms

• Predation predators consuming prey
• Most common methodPursuit and Ambush

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Interactions Among Organisms

• Animals that consume plants herbivores
• Animals that consume animals carnivores
• (can be further subdivided based on prey type,
  such as an insectivore)

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Interactions Among Organisms

• Defenses against predators
• Plant defenses
• spines, thorns
• leathery leaves
• toxic chemicals

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Interactions Among Organisms

• Defenses against predators
• Animal defenses

• armor, spines
• toxic chemicals
• camouflage

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Many amphibians secrete toxins from their skin
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Dendrobates terribilis is so poisonous that
merely handling an individual can admit enough
poison through the skin to produce symptoms of
poisoning
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The story of Homer and the Toad

• http//www.rotten.com/library/history/nature/invas
  ive-species/cane-toads/

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Interactions Among Organisms

• Competition
• individuals attempting to utilize common
  resources
• Intraspecific competition
• Interspecific competition

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The Ecological Niche

• An organisms adaptations, use of resources,
  lifestyle, and habitat.
• Fundamental vs. Realized Niche
• Example Tale of Two Anoles

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The Ecological Niche

• Fundamental vs. Realized Niche

Overlap
Brown anole out-competes green anole, therefore .
. .
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The Ecological Niche

• Fundamental vs. Realized Niche

Overlap
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The Ecological Niche

• Limiting Resources

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The Ecological Niche

• Competitive Exclusion

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The Ecological Niche

• Competitive Exclusion

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The Ecological Niche

• Competitive Exclusion

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The Ecological Niche

• Resource partitioning

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Keystone Species

• Single species that strongly influences an entire
  community.
• Example figs
• - frugivores depend upon fruit
• - usually avoid figs, but during certain times
  of the year, figs are only species bearing fruit
• - if figs were eliminated, many frugivores would
  die out

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Species Richness

• Number of different species in a community

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Species Richness
Forest
Grassland
ECOTONE
Where edge effect occurs Typically greater
species richness
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Species Richness

• Species Richness and Ecosystem Services

Purify air / water
Forests,Grasslands
Produce / maintain soil
Absorb CO2
Wildlife habitat
Freshwater systems
Moderate water flow
Mitigate flooding
Dilute / remove pollutants
Drinking water
Recreation
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Species Richness

• Species Richness and Community Stability
• Greater the richness Greater the stability