Bio 104 6/3/96

Dr. Barstow began the class by discussing overpopulation. He gave many examples of how we as human beings are killing the planet. Our biggest enemy is sex. I don't know what if any of his examples are testable, but do know that overpopulation is a major problem. The way to solve this is by using birth control or abstaining. You choose.

One thing Dr. Barstow said was: "If you took all the men that died in every war involving the United States (Rev.-Vietnam), they would be replaced in two days by new births"

Just go to the BLC and watch the video for more fun and happy facts just like that.

• community is a group of populations within an ecosystem composed of the plants, animals, and microorganisms that comprise it
• trophic levels:
  • almost all organisms are dependant on photosynthesis
  • Plants are the primary producers
    • photosynthesis
    • 100 billion tons of organic material a year is produced
    • organisms that eat plants are primary consumers -cows
    • secondary consumers are the organisms that eat primary consumers -us
• tertiary consumers -carnivores

• interactions include plants
• organisms may compete for same resource (competitive exclusion)
• if 2 species are competing for the same limited resource, one species will out-compete or eliminate the other
  • greatest among organisms on the same trophic level
• Niche- the role an organism plays in an ecosystem
  • 2 organisms cannot occupy the same niche
• Competition: balance between predator and prey; ensures survival of both

• Defense against predators:
  • Physical defenses of plants
  • thorns
  • spines
  • hairs that are sticky
• Chemical defenses of plants
  • limit one of the essential (12) amino acids

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