1. Chapter 3 – Communities and Biomes

2. Limiting Factors
A LIMITING FACTOR is any biotic or abiotic factor that limits a population’s growth
E.g. Sunlight, climate, temperature, water, nutrients/food, fire, space, predators
Limiting Factors in
Oregon Trail!

3. Succession
The orderly, natural changes in species in a community is called SUCCESSION
Two Types of Succession:
Primary Succession
Secondary Succession

4. Primary Succession
The colonization of completely barren land is called PRIMARY SUCCESSION
E.g. Volcanic eruption covers an area with fresh rock
The first organisms to colonize barren land are called PIONEER SPECIES
Lichens, mosses
A stable unchanging community is called a CLIMAX COMMUNITY
Lichen

5. Climax
Community
Pioneer Species

7. Secondary Succession
The changes that take place after an existing community is severely disrupted in some way is called SECONDARY SUCCESSION
Fire is the most common natural occurrence that will result in secondary succession
Floods, storms, human destruction

8. Secondary Succession

10. Section Biomes
A large group of ecosystems that share the same type of climax community is called a BIOME
Terrestrial biomes: on land
Aquatic biomes: in water
Freshwater
Saltwater
Estuaries (mixed water)

11. Aquatic Biomes
Most of the BIOMASS (organic matter) of the ocean is plankton
Plankton are microscopic plants and animals floating in the oceans

12. Photic vs. Aphotic Zone of Aquatic Biomes
PHOTIC ZONE – portion of a body of water that is penetrated by sunlight
(0 – 200 meters)
APHOTIC ZONE – portion of a body of water that sunlight cannot penetrate
(+200 meters)

15. Latitude Affects Climate
The equator gets direct sunlight all year
The poles get indirect sunlight for only part of the year
Equator = Hot
Poles = Cold
Areas around 30° north or south of the equator are deserts

17. Tundra Very cold; little rain; no trees;
Average Annual Temperature: -13° C
Annual Precipitation: cm
Permafrost: layer of permanently frozen soil
Common Plants: shallow rooted grasses, shrubs, small plants
Common Animals: lemmings, weasels, arctic foxes, hares, snowy owls, hawks, caribou, and reindeer

22. Taiga Cold; conifer trees; largest biome
Average Annual Temperature: 0° C
Annual Rainfall: 100 cm
Common Plants: Fir, hemlock, spruce trees
Common Animals: lynxes, snowshoe hares, caribou, red squirrels, voles, elk, red deer, moose, bears
Also called Boreal Forest or Coniferous Forest

28. Desert
Driest biome; very hot days, cold nights; very little plant life
Annual precipitation: less than 25cm
Average temperature: 25° C
Plants have adaptations to survive the dry climate: waxy coatings, small or reduced leaves, etc.
Common plants: cacti, small bushes and shrubs
Common animals: tortoises, snakes, lizards, scorpians, small rodents, coyotes, hawks, owls, roadrunners,

34. Grassland Few trees; fertile soil; large grazing mammals
Annual precipitation: 25 – 75cm
Average Temperature: 15° C
Common plants: grasses, wildflowers
Common animals: large grazing mammals, prairie dogs, jack rabbits, deer, elk
Sometimes called the “breadbaskets” of the world because the fertile soil is good for growing grains like oats, wheat, and rye

39. Temperate Deciduous Forest
We live here; 4 seasons; trees lose leaves in winter
Annual Precipitation: 70 – 150cm
Average Temperature: 10° C
Common Plants: maple, oak, birch, elm, ash, pine, cedar
Common Animals: squirrels, mice, rabbits , deer, bears, blue jays, cardinals, owls, hawks

45. Rain Forest
Greatest biodiversity (50% of all species); no seasons (hot and wet all the time);
Annual Precipitation: more than 200cm
Average Temperature: 25° C
Common plants: Trees, ferns, fungi*, vines
Common animals: insects, large cats, snakes, frogs, snails, lizards, birds, etc

49. Lakes and Oceans Aquatic; covers 75% of the Earth’s surface
Tides are caused by gravity from the moon and sun
Land in between high tide and low tide is called the INTERTIDAL ZONE
Plankton are at the bottom of the aquatic food chain