Evolution and Biodiversity: Origins, Niches, and Adaptations

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Evolution and Biodiversity Origins, Niches, and
Adaptations
Origins of Life Evolution and Adaptation Niches
Speciation, Extinction, and Biodiversity
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Rest assured, you are not alone!
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Key Concepts

• Origins of life

• Evolutionary processes

• Ecological niches

• Species formation

• Species extinction

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In the Beginningaccording to Science

• Chemical Evolution- (hypothesis) the first
  organic (life forming) molecules formed from
  inorganic molecules and energy formed protocells
  
• Lightening Heat (geothermal) Radiation (UV-sun)
• Produced by Stanley Miller and Harold Urey
• Biological Evolution-the change in a populations
  genetic make-up through successive generations
  (takes time not on an individual basis)
• Evidence from fossils (comparative anatomy) and
  DNA

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Animation
Stanley Miller's experiment animation.
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(No Transcript)
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Origins of Life
Fig. 5-2 p. 96 Refer to Fig. 5-4 p. 98
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The Theory Evolution

• Evolution Theory- the idea that all species
  descended from earlier, ancestral species
• Explains HOW life has changed and why life is so
  diverse
• Gene Pool- a populations genetic make-up (all
  the genes found in the individuals in a
  population)
• Microevolution- small genetic changes that occur
  in a population
• Macroevolution- long-term, large scale changes
  cause 2 outcomes
• New species are formed from ancestral species
• Other species are lost through extinction

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How Evolution Occurs

• Mutation- a random change in the structure
  (alleles) or number of DNA molecules in a cell
  99 fatal
• Mutagens-radiation (gama, x-ray, UV) or natural
  or man-made chemicals
• Abnormalities- mistakes made during the copy
  process when cells divide or during reproduction
• Natural Selection- the process through which some
  individuals exhibit traits that increase their
  chances of survival and ability to produce
  offspring 3 required conditions
• Variability of trait in species
• Must be heritable, able to be passed from one
  generation to another
• Differential Reproduction- increase the number
  of offspring or survivability of offspring of an
  individual

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Adaptation

• Natural Selections Causes (1) alleles or sets of
  alleles that are beneficial to become more common
  in successive generations and (2) other less
  beneficial alleles to become less common
• Adaptation- the improved ability of an organism
  to survive and reproduce a specific trait that
  increases these chances is called and adaptive
  trait often caused by the environment and do one
  of the following
• Species adapt through natural selection
• Migrate to another area
• Become extinct

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Figure 5-6 (1) Page 102
Directional Natural Selection
Proportion of light-colored snails in population
increases
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Figure 5-6 (2) Page 102
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Figure 5-6 (3) Page 102
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Natural Selection

• Coevolution- the hypothesis that the population
  of two interacting species (over a long-term) can
  cause changes in the gene pool that affect
  changes in the gene pool of the other species

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Ecological Niches and Adaptation

• Ecological niche

• Fundamental niche

• Habitat

• Realized niche

Fig. 5-7 p. 104
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Broad and Narrow Niches

• Generalist species- have broad niche, a
• wide variety to their habitat mice, rats,
• raccoons, coyotes, humans

• Specialist species- have a narrow niche,
• within a single habitat tiger salamander
• spotted owls, giant pandas

Refer to Spotlight p. 105
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Speciation, Extinction, and Biodiversity

• Speciation

• Geographic isolation

• Reproductive isolation

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Extinction

• Background extinction- due to
• environmental changes occurs slowly

• Mass extinction- catastrophic and or
• widespread

• Adaptive radiation- occurs just after a
• mass extinction when many niches are
• available in the changed environment