The Simple Bare The Simple Bare Necessities of LifeNecessities of Life

Chapter 2, Section 2Chapter 2, Section 2

pages 40-41pages 40-41

FoodFoodprovides organisms with provides organisms with

the energy and raw the energy and raw materials needed to:materials needed to:– carry on life processescarry on life processes– build and repair cellsbuild and repair cells– build and repair body partsbuild and repair body parts

How organisms get How organisms get their foodtheir food producers - make their own foodproducers - make their own food

– plantsplants use energy from the sun, water, and use energy from the sun, water, and

carbon dioxidecarbon dioxide

– microorganisms in the Movile microorganisms in the Movile CaveCave use chemicals in their environmentuse chemicals in their environment

How organisms get How organisms get their food (cont.)their food (cont.) consumers – must eat (consume) consumers – must eat (consume)

other organisms to get their foodother organisms to get their food– examples – mammals, reptilesexamples – mammals, reptiles

decomposers – must break down decomposers – must break down nutrients in dead organisms or nutrients in dead organisms or animal waste to get their foodanimal waste to get their food– examples – fungi, bacteriaexamples – fungi, bacteria

WaterWater most of the chemical most of the chemical

reactions involved in reactions involved in metabolism require watermetabolism require water– most living cells are 70% most living cells are 70%

waterwater– humans can survive about humans can survive about

three days without waterthree days without water

AirAir mixture of several gasesmixture of several gases

– mostly nitrogen, oxygen, and carbon mostly nitrogen, oxygen, and carbon dioxidedioxide

most living things use oxygen to most living things use oxygen to release energy from foodrelease energy from food

some organisms also need carbon some organisms also need carbon dioxide for photosynthesis (process dioxide for photosynthesis (process of converting energy in sunlight to of converting energy in sunlight to energy in food)energy in food)

A Place to LiveA Place to Live

somewhere to live that contains somewhere to live that contains all the things they need to surviveall the things they need to survive

some organisms require a large some organisms require a large amount of spaceamount of space– elephantelephant

some organisms do not require some organisms do not require very much space at allvery much space at all– bacteriabacteria

A Place to Live (cont.)A Place to Live (cont.)

space on earth is limitedspace on earth is limited–creates competition for creates competition for territoryterritory

Closure QuestionsClosure Questions

1.1. Why are decomposers categorized as Why are decomposers categorized as consumers? How do they differ from consumers? How do they differ from producers?producers?

2.2. Why are most cells 70% water?Why are most cells 70% water?

3.3. Could life as we know it exist on Could life as we know it exist on Earth if air contained only oxygen?Earth if air contained only oxygen?

4.4. How might a cave, an ant, and a lake How might a cave, an ant, and a lake meet the needs of an organism?meet the needs of an organism?