Chapter 3Communities and Biomes

Part 1

Ecosystem: interactions among populations in a community

• Consists of:– A community of organisms– The soil, water, and weather– Energy

Biome - a major ecosystem that shares the same type of climate and has similar life forms.

1. Salt water

2. Freshwater

3. Estuary

4. Terrestrial

CLIMATOGRAM - Measures two things:

• Average Temperature • Average Precipitation

TundraPermafrost - permanently frozen groundPlants - short roots; fast growing; perennials. Animals have thick fur / body fat / coloration.

Taiga / Coniferous ForestConifers - cone-bearing trees / bending branches / needles

as leaves. Animals also have thick fur / body fat.

DesertMost desert animals are nocturnal.

Estivation - sleeping during hot days.Plants have waxy leaves / spines.

GrasslandsMost animals have good vision and speed.

Plants have underground stems / survive fires.

Temperate / Deciduous ForestBroad-leaved trees lose their leaves yearly.

Some birds migrate.

Tropical Rain ForestArboreal - tree-dwelling animals

Trees / Plants:1. Canopy 2. Understory 3. Ground

Adaptation: the process by which a species becomes better suited to its environment.

• Migration• Thick fur• Coloration• Speed• Chemical defenses• Hibernation/ Estivation• Size• Thorns and stickers

Chapters 3-4Communities and Biomes /

Population

Part 2

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Succession: changes over time• Primary succession – new land caused by

avalanches, volcanoes, and glaciers

Succession: changes over time• Pioneer species – first species in an area

Succession: changes over time• Climax community – shows little or no change over time• Secondary succession – sequence of life after natural

disasters (ex. Forest fires)

1988 forest fire inYellowstone Nat’l Park

Population Dynamics• Exponential Growth - as a population gets

larger, it also grows faster. (p 97)• Carrying capacity - the maximum number

of organisms that an environment can support (p 98).

Limiting factors: Factors that affect an organism’s ability to survive.

• Density dependent factors:– Disease – Competition – Parasites – Food & water – Space

Density independent factors (abiotic factors):

– Temperature – Storms – Floods – Drought– Habitat disruption (logging,

burning, draining swamps, moving in exotic species)

Demography - human population growth

• Immigration - moving in• Emigration - moving out• Growth rate• Natality - birth rate

• Fatality - death rate