Chapter 3 The Earth’s Ecosystems
Bellringer • How many of the 7 Land Biomes can you list without looking at your notes or book?
Section 1 Land Biomes • Places that have similar abiotic factors typically have similar biotic factors • A Biome is a large area characterized by its climate and the plants and animals that live in the area. • A biome contains related ecosystems
1. Forests • Are often found in areas that have mild temperatures and plenty of rain. • Type depends on temperatures and rainfall.
There are 3 Types of forest Biomes: • Temperate Deciduous Forests • The word deciduous comes from a Latin word that means “to fall off” • Deciduous trees shed their leaves to save water during the winter or during the dry season • A variety of animals, such as bears, snakes and woodpeckers live in these forests
Coniferous Forests • Most trees in this forest are called conifers • Conifers produce seeds in cones and have special leaves shaped like needles • Leaves have a thick waxy coating with three functions: • Helps leaves from drying out • Protects needles from being damaged by cold weather • Allows them to keep their leaves year round
Trees that stay green all year and do not lose all of the leaves at one time are known as evergreen trees • Common animals are squirrels, insects, finches, porcupines, elk, moose, etc. • Very little light reaches the ground so few large plants can grow beneath the trees.
Tropical Rain Forests • Have more biological diversity than other places on Earth have • More than 100 different kinds of trees may grow in an area about ¼ the size of a football field. • Most animals live in the canopy, or the treetops • Most nutrients in the rainforest are found in the plants • The soil is very thin and poor in nutrition, so many trees grow above-ground roots for extra support.
Grasslands • Have many names, such as steppes, prairies and pampas. • Are found on every continent but Antarctica • Are often flat or have rolling hills.
1) Temperate Grasslands • Plants include grasses and other flowering plants • Have few trees • Fires, drought, and grazing prevent the growth of trees and shrubs • Temperatures support small seed-eating animals and large grass eaters.
2) Savannas • A savanna is a grassland that has scattered clumps of trees and seasonal rains • Are found in parts of Africa, India, and South America • During dry season, savanna grasses dry out and turn yellow, but their deep roots let them survive for many months without water. • Is home to many large herbivores, such as elephants, giraffes, zebras, and wildebeests.
Deserts • Deserts are biomes that are very dry and often very hot • Many plants and animals are found ONLY in deserts
Plant adaptations: • grow far apart • Shallow widespread roots that grow just under the surface • Fleshy stems and leaves to store water • Leaves have a waxy coating that helps prevent water loss
Animal Adaptations • Active only at night • Bury in the ground and are dormant during the dry season • Eat flowers or leaves and store the water under their shells
Tundra • The tundra is a biome that has very cold temperatures and little rainfall
Two types of tundra: • Polar Tundra • Found near the North and South Poles • Permafrost – layer of soil beneath the surface soil that stays frozen all the time • Only the surface soil defrosts during the short, cool summers • Shallow rooted plants such as grasses and small shrubs are common, and mosses and lichens grow beneath these plants • When the soil defrosts it is very muddy and insects lay eggs in the mud • Birds feed on these insects • Other animals include musk oxen, wolves, and caribou
REINDEER POLAR BEARS ALASKAN WILDFLOWERS ARCTIC TUNDRA AND ALASKAN PIPELINE
Alpine Tundra • Also has permafrost • Found at the top of tall mountains • Trees cannot grow on a mountain above an elevation called the tree line • Gets plenty of light and precipitation
Section 2 Marine Ecosystems
Life in the Ocean • Marine ecosystems are shaped by the following abiotic factors: • Water temperature • Water depth • Amount of sunlight that passes into the water
Animals and plants come in all shapes and sizes • Largest animals on Earth – blue whales • Plankton – tiny organisms that float near the surface of the water • Many are producers – use photosynthesis • Form the base of the ocean’s food chain
Temperature • As the water level increases, the temperature of the water decreases (the deeper the water the colder it is) • This temperature change not gradual
Ocean Temperature Zones • Surface Zone • The warm, top layer of ocean water that extends to 300 meters below sea level. • Sunlight heats the top 100 meters of the surface zone • Surface currents mix the heated water with the cooler water below • Temps vary with the times of the year and distance from the equator
Thermocline • A layer of water that extends from 300 meters below sea level to about 700 meters below sea level. • Water temperature drops with increased depth faster than it does in the other two zones
Deep Zone • Bottom layer that extends from the base of the thermocline to the bottom of the ocean. • Temperatures in this zone average a chilling 2⁰ C.
Temperature affects the animals that live in marine ecosystems • Some have adaptations for the temperatures • Some migrate from cold to warm areas of the ocean to reproduce • Affects whether some animals can eat • Sudden changes in temperature can cause some marine animals to die
Depth and Sunlight – The Four Oceanic Zones • The Intertidal Zone • Where the ocean meets the land • Exposed to the air for part of the day • Waves are always crashing on rock and sand • Animals that live here have adaptations to survive exposure to air and to keep from being washed away by the waves
The Neritic Zone • Water becomes deeper • Ocean floor starts to slope downward • Water is warm and receives a lot of sunlight • Many interesting plants and animals, such as corals, sea turtles, fishes, and dolphins live in this zone.
The Oceanic Zone • The sea floor drops sharply • Contains the deep water of the open ocean • Plankton at the water surface • Animals like fishes, whales, and sharks are found here • Ocean_Floors__Life_in_the_Neritic_and_Transition_Zones.asf
The Benthic Zone • The ocean floor • Deepest parts get no sunlight and are very cold • Many organisms get food from what sinks from above • Some get chemicals that escape thermal vents • Ocean_Floors__Life_in_the_Deep_Zone_BenthicZone.asf
Intertidal Areas • Found near the shore • Include: • Mudflats – worms and crabs live there • Sandy beaches – worms, clams, crabs, and plankton • Rocky shores – adaptations prevent them from being washed away • Rocky_Shore_Zones__Intertidal_Zone.asf
Coral Reefs • Found in warm, shallow areas of the neritic zone • Made up of small animals called corals • When corals die they leave their skeletons behind and layers of them form the reef • Home for many plants and animals including algae, fish, sponges, sea stars and sea urchins
Estuaries • This is an area where fresh water from streams and rivers spills into the ocean • The waters are always mixing so the salt content changes • Plants and animals must be able to survive these changing conditions • Fresh water is very nutrient rich so estuaries support large numbers of plankton, which then provide food for many other animals • estuaries.asf
The Sargasso Sea • Found in the middle of the Atlantic Ocean • Contains floating rafts of algae called sargassums
Polar Ice • The Arctic Ocean and ocean around Antarctica • Rich in nutrients and support large numbers of plankton • Animals such as polar bears and penguins live on the polar ice
Section 3 Freshwater Ecosystems
Stream and River Ecosystems • Water flows from melting ice and snow, or from a spring • Each stream of water that joins a larger stream is called a tributary • A very strong, wide stream is called a river • An important abiotic factor is how fast the water flows • Plants like the edges, fish live in open waters, and clams and snails live in muddy bottoms • Some producers like algae and moss are attached to rocks • Consumers suction to rocks or live under them
Pond and Lake Ecosystems • Life near Shore • Area closest to the edge of lake or pond is called the littoral zone • Sunlight reaches the bottom making it possible for plants and algae to grow • Plants become home to small animals such as snails and insects • Clams and worms bury in the mud • Frogs, salamanders, turtles, fish and snakes also live in this zone
Life Away from Shore • The Open-water zone extends from the littoral zone across the top of the water • Goes as deep as sunlight can reach • Home to bass, lake trout, and other fishes • Many photosynthetic plankton also live there Large mouth bass Lake trout
Beneath the open-water zone is the deep-water zone, where no sunlight reaches • Catfish, carp, worms, crustaceans, fungi, and bacteria live here • Often feed on dead organisms that sink from above CARP CATFISH CRUSTACEANS
Wetland Ecosystems • An area of land that is sometimes underwater or whose soil contains a great deal of moisture is called a wetland • Play important roles in flood control • Help to replenish underground water supplies
Marshes • Treeless wetland ecosystem where plants, such as grasses grow • Often found in shallow areas along the shores of lakes, ponds, rivers, and streams
Swamps • A wetland ecosystem in which trees and vines grow • Found in low-lying areas and beside slow-moving rivers • Essential_and_Endangered__Wetland_Biomes.asf (25:00)
From a Lake to a Forest • Over time, ponds and lakes fill with sediment • Plants grow in the new soil • Shallow areas fill in first and plants slowly grow closer and closer to the center of the pond or lake • What is left becomes a wetland, and eventually a forest