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Ecosystems Continually Change Over Time

Ecosystems Continually Change Over Time. Chapter 3 (pages 106 -161). Galapagos Islands. Volcanic island; distributed around the equator in the Pacific Ocean (isolated) 2 seasons: worm and dry Finches (birds): There are 13 species on the island  primary food source: seeds.

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Ecosystems Continually Change Over Time

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  1. Ecosystems Continually Change Over Time Chapter 3 (pages 106 -161)

  2. Galapagos Islands • Volcanic island; distributed around the equator in the Pacific Ocean (isolated) • 2 seasons: worm and dry • Finches (birds): There are 13 species on the island  primary food source: seeds

  3. 3.1 How Changes Occur Naturally in Ecosystems A. How Organism Change Q: How do these changes occur? Adaptation Characteristics that allow organisms to better survive and reproduce (3 types, chapter 1) Q: What if there is new environment? (eg. Forest fire)? • Speciation or extinction • Natural selection Evolution The process in which, over time, the best-adapted members of a species will survive and reproduce

  4. All the species are descended fromonefinch species on the mainland. • Each species has unique characteristics that allows them to thrive in their own niche, and not compete with other finches for resources. • Adaptive radiation: a form of natural selection when many different species appear from one original species.

  5. Activity 3.1A • 5 min • Page 109. DO “What to do”- “Mouth” and “eyes” • Match structural adaptation with correct advantage to the environment.

  6. Ecological Succession • Question: Which is more rapid: • Change from bare rock to a mature forest or • A burned down forest to an established forest? • Why? • Ecological succession: changes that take place over time in the types of organisms that live in an area

  7. Primary Succession • Occurs in an area where no soil exists such as bare rock • Takes a long time to complete ->up to several hundred years

  8. 1) Steps of Primary Succession • Starts with bare rock. • Wind carries spores of lichens that can survive on bare rock. • Weathering breaks down rock  soil begins to form

  9. d. Pioneer species make/improve soil; Insects and microorganism move in when soil forms • Pioneer Species are the first organisms to survive and reproduce. • Examples: Lichens and mosses

  10. As soil builds, other plants can grow (wildflowers and shrubs take root); More types of insects and microorganisms move in

  11. f. animals appear; tree seeds are transported to the area by birds or other animals Trees must be tolerant of lots of sunlight eg. Deciduous forest.

  12. g. Trees such as coniferous trees germinate and eventually shade out the deciduous trees I. A mature community form(stable and grows slowly.)

  13. 2. Secondary Succession: • when an area already has soil, but has had a disturbance like a forest fire or clearcut. • Happens more quickly than primary because there are already seeds, insects, worms etc. in the soil.

  14. Read page 115-117 • Complete “How natural events affect ecosystem” check at the end of the class HW. • Read page 3.2 complete “Human influence Ecosystem handout” • Pg 121 Q 2-5, 6, 9,11,

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