Ch. 17 & 18 notes

Ch. 17 & 18 “Biological Communities & The Environment

I. How Organisms Interact in CommunitiesA. Coevolution –back and forth evolutionary

adjustments between interacting members of an ecosystem. Ex: plants and the animals who pollinate them.

B. Predation-act of one organism killing another for food. Ex: Lion eating zebras, snakes eating mice1. plant defenses against animals include

thorns, sticky hairs, tough leaves, prickles, and chemicals.

C. Symbiosis-two or more species live together in a close relationship.1. Parasitism-symbiosis that is harmful to the

host organism. Ex: tapeworm in a dog or tick on a human.

2. Mutualism-symbiotic relationship in which both participating species benefit. Ex: Ant on acacia tree

3. Commensalism-symbiotic relationship in which one species benefits and the other is neither harmed or helped. Ex: Clown fish that lives in the sea anemone.

II. How Competition Shapes CommunitiesA. Competition-when two species use the

same resources. Species compete for resources such as food, nesting site, living space, light, minerals, water.

B. Niche-how an organism lives; its way of life.

C. Biodiversity-the variety of living organisms in a community.

III. Major Biological CommunititesA. Climate-the weather conditions in any

given area. This determines where species live. The two most important elements of climate are temperature and moisture. The farther away from the equator, temperature and moisture decrease; closer to the equator, temperature and moisture increase.

B. Biome-a major biological community that occurs over a large area of land.

C. Seven major terrestrial biomes include:

Tropical rainforest-the most diverse biome home to half the Earth’s living organisms, located along the equator

Savanna

Taiga - Russia

Tundra

Desert

Temperate Grassland- most of the central part of the U.S. is temperate grassland

Temperate Forest

D. Three major marine biomes include:Shallow ocean water, open sea surface, deep

sea waters.

IV. Global ChangeA. Acid Rain-caused by airborne pollutants

that lower the pH of the rain. Thousands of lakes are “dying” due to low pH levels and forests are being destroyed.

B. Ozone layer-being destroyed by chemical called CFC’s.

C. Greenhouse Effect-caused by gases such as CO2 that trap heat in the earth’s atmosphere.

D. Global Warming-overall increase in earth’s temperature.

V. Effects on EcosystemA. Biological Magnification-the accumulation

of increasingly large amounts of toxic chemicals within each level of the food chain.

B. Three non-replaceable resources are being consumed or destroyed at a rapid rate:1. species of living things2. topsoil3. ground water- water trapped beneath the

soil in porous rocks

C. Rapid growth of the human population places stress on the Earth’s ecosystem.The human population growth has caused faster extinction of animal and plant species due to:

Destruction of rainforest for lumberOverhuntingPollution

VI. Solving Environmental ProblemsA. Methods to reduce pollution include:

laws and stricter standards, taxes on polluterseducation of the public.

B. Each individual can help by: recycling, using alternative means of transportation, help educate people.

C. Two success stories of solving environmental include:1. the Nashua River

Massachusetts Clean Water Act of 1966

2. Lake Washington