Chapter 3 – Communities and Biomes

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!

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

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

Climax Community Pioneer Species

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

Secondary Succession

Section 3.2 - 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)

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

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)

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

Tundra Very cold; little rain; no trees; Average Annual Temperature: -13° C Annual Precipitation: 10-15 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

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

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,

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

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

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

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