Changing Ecosystems
What do you call the normal, gradual changes that occur in the types of species that live in an area? (p.150)
Succession
What do we call the large geographic areas that have similar climates and ecosystems? (p.154)
Biomes
Which biome is characterized by four distinct seasons each year? (p.156)
Temperate deciduous forests have an annual precipitation between 75cm and 150cm per year, temperatures that range from below freezing in winter to 30°C (86°F) or more in the summer, and climax communities of deciduous trees that lose their leaves in the autumn.
In North America, common animal species: white-tailed deer, raccoons, opossums, porcupines, red foxes, as well as hawks, owls, cardinals, woodpeckers, etc.
What is an example of a flowing fresh water ecosystem? (p.163)
Rivers, as well as streams, brooks, etc.
Naturally fast-flowing streams usually have clearer water and higher oxygen content than slow-flowing streams.
Most nutrients that support life in flowing-water ecosystems are washed into the water from land. In areas where water movement slows, debris settles at the bottom. These environments tend to have higher nutrient levels and more plant growth.
How many zones are there in a tropical rain forest? (p.158-159)
There are four zones.
1. The forest floor is home to many insects and the largest mammals in the rainforest generally live here.
2. The understory is a dark, cool environment under the canopy leaves but above the ground. Many insects, reptiles, and amphibians live here.
3. The canopy includes the upper parts of the trees. It's full of life -- insects, birds, reptiles, and mammals.
4. The emergents are giant trees that are much higher than the average canopy tree. Birds, such as the macaw, and insects are found here.
What type of succession occurs in a place that was previously without any plants, such as a newly formed volcanic island? (p.150)
Primary Succession
The land portion of Earth can be divided into how many major biomes? (p.154)
There are seven major biomes:
1. Desert
2. Grassland
3. Tropical Rain Forest
4. Temperate Rain Forest
5. Temperate Deciduous Forest
6. Taiga
7. Tundra
Which biome is the most biologically diverse (has the largest variety of different plant and animal species)? (p.158)
The tropical rain forest has an average temperature of 25°C (77°F), and receives between 200cm and 600cm of precipitation each year.
Common animal species: insects, reptiles, amphibians, jaguar, gorillas, chimpanzees, sloths, macaw, toucans, etc.
What is an example of a standing fresh water ecosystem? (p.163-164)
Lakes, ponds, and wetlands.
Pond and lake water hardly moves. It contains more plants than flowing water environments contain.
Lakes are larger and deeper than ponds. They have more open water because most plant growth is limited to shallow areas along the shoreline. Organisms found in the shallow shoreline area are similar to those found in ponds.
Ponds are shallow, and filled with animal and plant life. Sunlight usually penetrates to the bottom. Because of the lush growth in pond environments, they tend to be high in nutrients.
The arrival of what begins primary succession? (p.150)
Pioneer species such as lichens.
What type of succession begins in a place that already has soil, and was once the home of living organisms, such as after a forest fire? (p.151)
Secondary Succession
What are the two most important climatic factors that affect life in an area? (p.154)
Temperature and precipitation
Which biome has between 200cm and 400cm of precipitation each year, average temperatures between 9°C to 12°C (48°F to 53°F), and forests dominated by trees with needlelike leaves? (p.157)
Temperate rain forests can be found in New Zealand, southern Chile, the Pacific Northwest of the United States, and elsewhere around the world. Trees including the Douglas fir, western red cedar, and spruce are found there.
Common animal species: black bear, wolf, cougar, bobcat, northern spotted owl, salamanders, etc.
What is a region of land that is wet for all or most of the year? (p.165)
Wetlands are found in regions that lie between landmasses and water. Other names for wetlands include swamps, bogs, marshes, and fens.
They are fertile ecosystems, but only plants that are adapted to water-logged soil survive there. Wetlands provide flood control, clean water, and are home to lots of wildlife.
Common animal species: beavers, muskrats, alligators, bog turtles; and migratory birds use wetlands for breeding grounds.
Why might you find similar trees on the top of a mountain in the southern United States as the ones that exist in the taiga in northern Canada? (p.156)
There are similar climates at high altitudes (on top of mountains) and at extreme northern latitudes.
What do we call the first living things that inhabit an area? (p.150)
Pioneer Species, such as lichens, survive drought, extreme heat and cold, and other harsh conditions, and often start the soil-building process.
Which biome can be found just south of the north pole, or at high elevations? (p.155)
The tundra is a cold, treeless biome with less than 25cm of precipitation each year. It has a short growing season, permafrost, and winters that can be six months long. The average daily temperature is about -12°C (only about 10°F).
The arctic tundra is the biome that encircles the Earth just south of ice-covered seas in the Northern Hemisphere.
The alpine tundra is the biome at high mountain altitudes, which vegetation and climate are similar to those of the artic tundra (although there is no permafrost).
Which biome is the driest on Earth, and has plants and animals that are adapted to survive extreme conditions? (p.160)
The desert receives less than 25cm of rain each year, and supports little plant life. Some desert areas receive no rain for years. When rain comes, it quickly drains away, and any water that remains evaporates quickly.
Common animal species: scorpions, meerkat, kangaroo rat, camels
What saltwater ecosystem is formed from the calcium carbonate shells secreted by certain species of aquatic animals? (p.167)
Coral reefs are made of the skeletal remains of corals. They are diverse ecosystems that are homes to colorful fish and a large variety of other organisms.
Reefs do not adapt well to long-term stress. Runoff from fields, sewage, and increased sedimentation from cleared land harm reef ecosystems.
Do rivers or lakes support more species? (p.163-164)
Lakes contain more plants than flowing-water environments like streams contain. The population of organisms in the shallow waters of a lake are high, and there are fewer types of organisms that live in the deeper water.
Lakes have standing water, lower oxygen levels, and rich plant growth in the shallow water. Rivers have swift moving water, high oxygen levels (atmospheric air gets mixed in from its tumbling and splashing), and a rocky bottom with very little plant life.
How do pioneer species, such as lichens, contribute to the formation of new soil? (p.151)
Lichens help break down rock along with weather and erosion. When lichens die, they decay, and add small amounts of organic matter to the rock.
Plants such as mosses and ferns can then grow in this new soil, and add more organic material when they die. As the soil layer thickens, more types of plants (grasses, flowers, shrubs, trees) can start to grow, and then insects, animals and birds move into the area.
Which biome is the world's largest, located south of the tundra between the latitudes of 50°N and 60°N? (p.156)
The taiga has long, cold winters. Precipitation there is between 35cm and 100cm each year. Dense forests of cone-bearing evergreen trees are common. Although the winter is long and cold, it is warmer and has more precipitation than the tundra.
Common animal species: moose, lynx, shrews, bears, foxes
What adaptation do desert animals have that allow them to survive the extreme conditions? (p.160)
Some, like the kangaroo rat, never need to drink water. They get all the moisture they need from the breakdown of food during digestion.
Most are only active during the night, late afternoon, or early morning when temperatures are less extreme.
Similarly, desert plants like cacti, are able to store water which enables them to survive the extreme dryness and hot and cold temperatures of the desert.
In which part of the ocean would you find plankton, which make up the foundation of the food chain of the open ocean? (p.167)
The ocean is divided into different life zones, based on the depth to which sunlight penetrates the water. The lighted zone is the upper 200m or so of the ocean, and is where plankton is found.
Below 200m is the dark zone of the ocean. Animals living in this region feed on material that floats down from the lighted zone, or on other organisms found in the dark zone. And, a few organisms are able to produce their own food through chemosynthesis.
The African Savanna and Prairies in North America are examples of what type of biome?
Grasslands
What do you call the stable end-stage of ecological succession in which a community of plants is in balance, in the absence of disturbance? (p.153)
Climax community is where new trees grow when older trees die, and while the individual trees may change, the species remains stable.
There are fewer changes of species in a climax community over time, as long as the community isn't disturbed by natural disasters (like wildfires or avalanches), or human activities.
What adaptation(s) might animal species that live in the tundra or the taiga have that makes them well-suited for those biomes? (p.155-156)
Some species, such as arctic hares and ptarmigans, turn white in the winter, and are brown in the warmer months to better camouflage.
Many have thick fur or feathers.
Some, such as the lynx, have broad, heavily furred feet that act like snowshoes to prevent them from sinking in the snow.
Which biome would be ideal for growing crops and raising cattle? (p.161)
Grasslands are found in both temperate and tropical regions with 25cm to 75cm of precipitation per year. They are dominated by climax communities of grasses.
Common animal species:
In the US... bison, prairie dogs, coyote
African savannas... wildebeests, impalas, zebras
Australia outback... kangaroos, emu
What is the portion of the shoreline that is covered with water at high tide and exposed to the air during low tide? (p.168)
The intertidal zone.
Organisms that live in the intertidal zone, such as sea stars and periwinkles, must be adapted to dramatic changes in temperature, moisture, and salinity, and must be able to withstand the force of wave action.
Bogs, marshes, swamps, floodplains, and lagoons, are different names for what type of biome?
Wetlands
Which takes longer, primary succession or secondary succession? (p.150-151)
Primary succession takes longer because there is no pre-existing soil.
Secondary succession is quicker because there is soil, and often there are seeds of species that lived there previously that are able to survive.
What do you call the thick layer of land beneath the soil that remains frozen throughout the year? (p.155)
Permafrost occurs mainly in the artic tundra regions.
Why would soil in a tropical rainforest make poor farmland? (p.158)
Although tropical rainforests support a huge variety of organisms, the soil of the rainforest contains few nutrients. Over the years, nutrients have been washed out of the soil by rain.
What do we call the area where a river meets an ocean? (p.168)
Estuaries contain a mixture of fresh water and salt water. Other names for estuaries include bays, lagoons, harbors, inlets, and sounds. They are located near the coastline and border the land.
Estuaries are extremely fertile, productive environments because freshwater streams bring nutrients washed from inland soils. Therefore, nutrient levels in estuaries are higher than in freshwater ecosystems or other saltwater ecosystems.
Common animal species: shrimp, crabs, clams, oysters, snails, worms, and fish
In which zone (or layer) of the tropical rainforest do sloths live?
The canopy.
Sloths are arboreal neotropical animals, meaning they live in the trees of Central and South America!