1. CHAPTER 17
ECOSYSTEMS

2. Ecology- the study of interactions of living organisms with one another and with their physical environment
Habitat- place where a
particular population of
a species lives
Community- the many
different species that
live together in a habitat

3. Ecosystem- includes a community and all the physical aspects of its habitat
Biotic Factors- living
organisms in a habitat
Abiotic Factors- physical
aspects of a habitat

4. Producers- organisms that make energy-storing molecules (plants)
Consumers- organisms that
consume plants or other
organisms to obtain energy
Trophic Level- shows how
energy moves through an ecosystem
Sunproducerconsumerconsumer

5. Food Chain- path of energy through the trophic levels of an ecosystem
Food Web- interconnected group of food chains

6. Food Chains: 1st level 2nd level 3rd level Producers
Herbivores- eat primary producers
3rd level
Carnivores- eat herbivores
Omnivores- both herbivores and carnivores
Detrivores- obtain energy from organic wastes and dead bodies
Decomposers- bacteria and fungi that cause decay

8. BIOLOGICAL COMMUNITIES
CHAPTER 18
BIOLOGICAL COMMUNITIES

9. Predation- the act of one organism feeding on another
Parasitism- one organism feeds
on and usually lives on or in
another organism
Symbiosis- two or more species live together in a close, long-term association

10. Mutualism- a symbiotic relationship in which both participating species benefit
Commensalism- a symbiotic relationship in which one species benefits and the other is neither harmed nor helped
Competition- biological interaction
that occurs when two species use
the same resource

11. Niche- how an organism lives, the “job” it performs within the ecosystem
Climate- prevailing weather conditions in any given area (temperature and moisture)
Biome- a major biological community that occurs over a large area of land

12. 7 Land Biomes

13. Tropical Rain Forests:
cm of rain per year
½ of the Earth’s terrestrial species
(2 million)

14. Deserts:
Fewer than 25cm of rain per year
Vegetation is sparse

15. Savannas: 90-150cm of rain per year
Grasslands found between rain forests and deserts

16. Temperate Deciduous Forests:
75-250cm precipitation per
year
Trees shed their leaves in the fall

17. Temperate Grasslands:
Prairies with fertile soil used for farming in Central United States

18. Taiga:
Cold, wet climates; long winters
Coniferous forests

19. Tundra: Between taiga and permanent ice of the North Pole
Less than 25cm of precipitation per year
Covers 1/5 of the Earth’s land surface

20. Freshwater Communities:
Lakes, ponds, streams and rivers
(2.1% of the Earth’s surface)
Strongly connected to terrestrial habitats

21. Marine Communities: Oceans cover ¾ of the Earth’s surface
Average depth = 3km (1.9 miles)