The Simple Bare Necessities of Life

1
The Simple Bare Necessities of Life

• Chapter 2, Section 2
• pages 40-41

2
Food

• provides organisms with the energy and raw
  materials needed to
• carry on life processes
• build and repair cells
• build and repair body parts

3
How organisms get their food

• producers - make their own food
• plants
• use energy from the sun, water, and carbon
  dioxide
• microorganisms in the Movile Cave
• use chemicals in their environment

4
How organisms get their food (cont.)

• consumers must eat (consume) other organisms to
  get their food
• examples mammals, reptiles
• decomposers must break down nutrients in dead
  organisms or animal waste to get their food
• examples fungi, bacteria

5
Water

• most of the chemical reactions involved in
  metabolism require water
• most living cells are 70 water
• humans can survive about three days without water

6
Air

• mixture of several gases
• mostly nitrogen, oxygen, and carbon dioxide
• most living things use oxygen to release energy
  from food
• some organisms also need carbon dioxide for
  photosynthesis (process of converting energy in
  sunlight to energy in food)

7
A Place to Live

• somewhere to live that contains all the things
  they need to survive
• some organisms require a large amount of space
• elephant
• some organisms do not require very much space at
  all
• bacteria

8
A Place to Live (cont.)

• space on earth is limited
• creates competition for territory

9
Closure Questions

1. Why are decomposers categorized as consumers?
   How do they differ from producers?
2. Why are most cells 70 water?
3. Could life as we know it exist on Earth if air
   contained only oxygen?
4. How might a cave, an ant, and a lake meet the
   needs of an organism?