1. Interactions of Living Things
7th Grade Science

2. PART 1

3. Biotic vs. Abiotic
-Biotic – all LIVING parts of environment. -ex: tree, fly, people -Abiotic – all NONLIVING parts of environment. -ex: water, soil, sunlight, temp.

4. Levels of Environmental Organization
Organism
Population – all same species that live in area
Community – all species that live in area
Ecosystem – community plus abiotic factors
5. Biosphere – all ecosystems, anywhere life exists

6. Salt Marsh – page 6
-What are some biotic factors in this marsh? *cordgrass *jellyfish *egret *heron *algae *marsh crab -What are some abiotic factors? *water *sunlight *soil *temperature

7. PART 2
LIVING THINGS NEED ENERGY

8. Players in the Energy Game
-Producers – use sunlight to make food -ex: plants, algae -Consumers – eat other organisms -herbivore – eats only plants -omnivore – eats both plants & animals -carnivore – eats only animals -scavenger – eats dead plants & animals

9. -Decomposers – get energy by breaking down dead organisms -ex: bacteria & fungi -called nature’s recyclers

10. Food Chains
-Diagram that shows energy flow from one organism to another -Why are these rare in nature?

11. Food Webs
-More realistic than chains -Interconnected chains show feeding relationships in ecosystem -Arrows – is eaten by

13. Energy Pyramids
-diagram that shows loss of energy as it passes through food chains
Amount of energy
decreases
as you
move up
the levels
Amount of
toxins
increase
as you
move up
the levels

14. PART 3
TYPES OF INTERACTIONS

15. Limiting Factors
-Scarce resource that limits size population can grow -ex: food becomes a limiting factor when population outgrows amount of food available

16. Carrying Capacity
-Largest population an environment can support at any given time -When a population grows larger than carrying capacity, limiting factors cause individuals to die or leave

17. Competition
-2 or more individuals or populations trying to use the same resource.

18. Predators vs. Prey
-Predator – organism that eats the prey -wide variety of methods & abilities for getting food
A cheetah’s speed gives it an advantage over other predators competing for the same prey

19. Prey Adaptations
-Prey have methods to keep from being eaten: 1. stay in groups 2. camouflage 3. defense (poison, chemical, physical) 4. burrowing

20. Stay in groups or Herds

21. Camouflage

22. Defense

23. Warning Coloration

24. Symbiosis
-Close, long-term association between members of 2 or more species -classified as one of the following: 1. mutualism 2. commensalism 3. parasitism

25. Mutualism
-Both organisms benefit from the interaction. -ex: you & e.coli in your stomach!!!

26. Commensalism
-One organism benefits, the other is unaffected. -ex: sharks & remoras

27. Parasitism
-One organism benefits, the other is harmed. -organism that benefits - parasite -organism harmed - host
-ex: Caterpillar & Wasp eggs