Chapter 50 (pgs. 1092-1119) An Introduction to Ecology and the Biosphere AP Minknow The role of abiotic factors in the formation of biomes. Features of freshwater and marine biomes. Major terrestrial biomes and their characteristics.

The Scope of Ecology  1.Define ecology and identify the two features of organisms that ecologists try to explain. Discuss examples of experiments that examine these features.  2.Distinguish between the abiotic and biotic components of the environment.  3.Describe the relationship between ecology and evolutionary biology.  4.Distinguish among organismal ecology, population ecology, community ecology, ecosystem ecology, and landscape ecology.  5.Define the precautionary principle and illustrate its usefulness with regard to the ecological issues facing society. Factors Affecting Distributions of Organisms  6.Describe the flowchart of inquiry used to determine what limits the geographic distribution of a particular species. 7.Describe the problem of introduced species and the specific problems posed by the introduction of African bees and zebra mussels. 8.Explain the "tens rule."

9.Explain how habitat selection can limit the range of otherwise suitable habitats.  10.Describe and illustrate biotic and abiotic factors that affect the distribution of organisms.  11.Explain how climate affects the geographic distribution of organisms.  12.Define and illustrate the concept of a microclimate.  13.Explain how the retreat of North American glaciers 16,000 years ago influenced the distribution of trees. Aquatic and Terrestrial Biomes 14.Distinguish among the various zones found in aquatic biomes.  15.Define and compare the many types of freshwater and marine biomes.  16.Describe the characteristics of the major terrestrial biomes: tropical forest, savanna, desert, chaparral, temperate grassland, temperate forest, taiga, and tundra. The Spatial Scale of Distributions  17.Explain why the distribution of a species is often not easily accounted for.

50.1 Ecology is the study of interactions between organisms and the environment Is the scientific study of the (complex) interactions between organisms and the environment These interactions Determine both the distribution of organisms and their abundance

Ecology and Evolutionary Biology Events that occur in ecological time Affect life on the scale of evolutionary time

50.2 Interactions between organisms and the environment limit the distribution of species. Kangaroos/km2 > 20 10–20 5–10 1–5 0.1–1 < 0.1 Limits of distribution Climate in northern Australia is hot and wet, with seasonal drought. Red kangaroos occur in most semiarid and arid regions of the interior, where precipitation is relatively low and variable from year to year. Southeastern Australia has a wet, cool climate. Southern Australia has cool, moist winters and warm, dry summers. Tasmania

Organisms and the Environment The environment of any organism includes Abiotic, or nonliving components Biotic, or living components All the organisms living in the environment, the biota

Abiotic Factors

Climate prevailing weather conditions in a particular area. Mainly formed by 4 abiotic factors Temp, wind, water, light Macroclimate Global, regional, and local patterns Microclimate Very fine patter such as the climate for an ant population under a rock

50.4: Climate largely determines the distribution and structure of terrestrial biomes Is particularly important in determining why particular terrestrial biomes are found in certain areas

Climate and Terrestrial Biomes Climate has a great impact on the distribution of organisms, as seen on a climograph Desert Temperate grassland Tropical forest Temperate broadleaf forest Coniferous Arctic and alpine tundra Annual mean precipitation (cm) Annual mean temperature (ºC) 100 200 300 400 30 15 15 Figure 50.18

are classified by their abiotic and biotic factors. Biomes are the major types of ecological associations that occupy broad geographic regions of land or water are classified by their abiotic and biotic factors. 30N Tropic of Cancer Equator Capricorn 30S Key Tropical forest Savanna Desert Chaparral Temperate grassland Temperate broadleaf forest Coniferous forest Tundra High mountains Polar ice Figure 50.19

Climate largely determines the distribution and structure of terrestrial biomes. Because there are latitudinal patterns of climate over the Earth’s surface, there are also latitudinal patterns of biome distribution. A climograph denotes the annual mean temperature and precipitation of a region. Temperature and rainfall are well correlated with different terrestrial biomes, and each biome has a characteristic climograph. Most terrestrial biomes are named for major physical or climatic features or for their predominant vegetation. Vertical stratification is an important feature of terrestrial biomes. The canopy of the tropical rain forest is the top layer, covering the low-tree stratum, shrub understory, ground layer, litter layer, and root layer. Grasslands have a canopy formed by grass, a litter layer, and a root layer. Stratification of vegetation provides many different habitats for animals. Terrestrial biomes usually grade into each other without sharp boundaries. The area of intergradation, called the ecotone, may be narrow or wide. The species composition of any biome differs from location to location. Biomes are dynamic, and natural disturbance rather than stability tends to be the rule. Hurricanes create openings for new species in tropical and temperate forests. In northern coniferous forests, snowfall may break branches and small trees, producing gaps that allow deciduous species to grow. As a result, biomes exhibit patchiness, with several different communities represented in any particular area. In many biomes, the dominant plants depend on periodic disturbance. For example, natural wildfires are an integral component of grasslands, savannas, chaparral, and many coniferous forests. Human activity has radically altered the natural patterns of periodic physical disturbance. Fires are now controlled for the sake of agricultural land use. Humans have altered much of the Earth’s surface, replacing original biomes with urban or agricultural ones.

What Is a Biome? For each biome, plots of seasonal temperature and precipitation patterns are given. Activity of different types of organisms throughout the year are shown. Level of activity is shown by width of horizontal bar. Growth forms of plants are described, as are patterns of species richness (number of species).

What Is a Biome? General descriptions of the biomes cannot describe all the variation existing in each. Boundaries between biomes are somewhat arbitrary; in many places the biomes merge into one another.

What Is a Biome? Tundra Arctic and at high elevations. Vegetation is low-growing perennials. Arctic tundra is underlain by permafrost. Soils can be wet because of poor drainage. Animals migrate or go dormant for much of the year.

Tundra (Part 1)

Tundra (Part 2)

Tundra (Part 3)

What Is a Biome? Boreal forest Long, cold winters; short summers. Dominated by evergreens in the Northern Hemisphere: can start photosynthesis quickly in the short growing season. Have only a few tree species. Dominant mammals, (e.g., moose and hares, eat leaves).

Boreal Forest and Temperate Evergreen Forest (Part 1)

Boreal Forest And Temperate Evergreen Forest (Part 2)

Boreal Forest And Temperate Evergreen Forest (Part 3)

What Is a Biome? Temperate deciduous forest Precipitation is distributed evenly, but temperatures fluctuate dramatically. Forests dominated by deciduous trees that lose leaves during the cold season. Temperate forests with the most species were not covered by glaciers during the Pleistocene.

Temperate Deciduous Forest (Part 1)

Temperate Deciduous Forest (Part 2)

Temperate Deciduous Forest (Part 3)

What Is a Biome? Temperate grasslands Dry much of the year; hot summers and cold winters. Much of this biome has been converted to agriculture. Rich in species; grasses, sedges, and forbs. Plants are adapted to grazing and fire.

Temperate Grasslands (Part 1)

Temperate Grasslands (Part 2)

Temperate Grasslands (Part 3)

What Is a Biome? Cold desert In continental interiors and rain shadows. Dominated by few species: low-lying shrubs. Plant growth concentrated in spring. Plants produce lots of seed that supports seed-eating birds and rodents.

Cold Desert (Part 1)

Cold Desert (Part 2)

Cold Desert (Part 3)

What Is a Biome? Hot desert At 30° north and south. More species and structurally diverse vegetation than cold deserts. Succulents are common. Many annuals grow after a rainfall. Pollination and fruit dispersal by animals.

Hot Desert (Part 1)

Hot Desert (Part 2)

Hot Desert (Part 3)

What Is a Biome? Chaparral On western sides of continents with cool ocean currents offshore. Winters are cool and wet, summers warm and dry. Adapted to fire. Shrubs and low trees with tough, evergreen leaves. Annuals abundant, supports lots of rodents.

Chaparral (Part 1)

Chaparral (Part 2)

Chaparral (Part 3)

What Is a Biome? Thorn forest and tropical savanna On equatorial sides of hot deserts. Rainfall may be heavy in summer. Small trees may drop leaves in dry winter. Acacia are common. Savannas: grasslands with scattered trees; supports large grazing and browsing mammals and large predators.

Thorn Forest And Tropical Savanna (Part 1)

Thorn Forest And Tropical Savanna (Part 2)

Thorn Forest And Tropical Savanna (Part 3)

What Is a Biome? Tropical deciduous forest Most trees lose leaves during the dry season. Many flower while they are leafless. Most have been cleared for agriculture and cattle grazing.

Tropical Deciduous Forest (Part 1)

Tropical Deciduous Forest (Part 2)

Tropical Deciduous Forest (Part 3)

What Is a Biome? Tropical evergreen forest Equatorial regions with high rainfall. Highest species richness of all biomes. Up to 500 tree species per km2. Also highest overall productivity. Most nutrients are tied up in vegetation; soils are poor.

Tropical Evergreen Forest (Part 1)

Tropical Evergreen Forest (Part 2)

Tropical Evergreen Forest (Part 3)

52.3 What Is a Biome? Distribution of biomes depends on climate, but other factors are also important, especially soil fertility and fire. Australian deserts are different from others. Succulent plants are not found there because of frequent fires. The soils are extremely poor, and plant leaves difficult to digest; herbivores eat very little.

A tropical rain forest in Borneo Tropical forests are found close to the equator. Tropical rain forests receive constant high amounts of rainfall (200 to 400 cm annually). In tropical dry forests, precipitation is highly seasonal. In both, air temperatures range between 25°C and 29°C year round. Tropical forests are stratified, and competition for light is intense. Animal diversity is higher in tropical forests than in any other terrestrial biome. Flora – high biomass and diversity Fauna – sloths, snakes, monkeys, birds, leopards, insects TROPICAL FOREST A tropical rain forest in Borneo Figure 50.20

The Sonoran Desert in southern Arizona Deserts occur in a band near 30° north and south latitudes and in the interior of continents. Deserts have low and highly variable rainfall, generally less than 30 cm per year. Temperature varies greatly seasonally and daily. Desert vegetation is usually sparse and includes succulents such as cacti and deeply rooted shrubs. Many desert animals are nocturnal, so they can avoid the heat. Desert organisms display adaptations to allow them to resist or survive desiccation. Flora – sparse, cacti, drought-resistant plants Fauna – jackrabbits, owls, lizards, snakes, tortoises Figure 50.20 DESERT The Sonoran Desert in southern Arizona

A typical savanna in Kenya Savanna is found in equatorial and subequatorial regions. Rainfall is seasonal, averaging 30–50 cm per year. The savanna is warm year-round, averaging 24–29°C with some seasonal variation. Savanna vegetation is grassland with scattered trees. Large herbivorous mammals are common inhabitants. The dominant herbivores are insects, especially termites. Fire is important in maintaining savanna biomes.Flora – low-scattered trees, grasses Fauna – lions, elephants, wildebeests, antelope SAVANNA A typical savanna in Kenya Figure 50.20

An area of chaparral in California Chaparrals have highly seasonal precipitation with mild, wet winters and dry, hot summers. Annual precipitation ranges from 30 to 50 cm. Chaparral is dominated by shrubs and small trees, with a high diversity of grasses and herbs. Plant and animal diversity is high. Adaptations to fire and drought are common.Flora – shrubs, small trees, and grasses Fauna – amphibians, birds, reptiles, deer CHAPARRAL An area of chaparral in California

Sheyenne National Grassland in North Dakota Temperate grasslands exhibit seasonal drought, occasional fires, and seasonal variation in temperature. Large grazers and burrowing mammals are native to temperate grasslands. Deep fertile soils make temperate grasslands ideal for agriculture, especially for growing grain. Most grassland in North America and Eurasia has been converted to farmland.Flora – grasses Fauna – prairie dogs, bison, foxes, ferrets, grouse, snakes, lizards Sheyenne National Grassland in North Dakota Figure 50.20 TEMPERATE GRASSLAND

Rocky Mountain National Park in Colorado Coniferous forest, or taiga, is the largest terrestrial biome on Earth. Coniferous forests have long, cold winters and short, wet summers. The conifers that inhabit these forests are adapted for snow and periodic drought. Coniferous forests are home to many birds and mammals. These forests are being logged at a very high rate and old-growth stands of conifers may soon disappear.Flora – wind-blown conifers (evergreens, stunted growth, modified spikes for leaves Fauna – caribou, wolves, moose, bear, rabbits, lynx Rocky Mountain National Park in Colorado CONIFEROUS FOREST Figure 50.20

TEMPERATE BROADLEAF FOREST Temperate broadleaf (deciduous) forests have very cold winters, hot summers, and considerable precipitation. A mature temperate broadleaf forest has distinct vertical layers, including a closed canopy, one or two strata of understory trees, a shrub layer, and an herbaceous layer. The dominant deciduous trees in Northern Hemisphere broadleaf forests drop their leaves and become dormant in winter. In the Northern Hemisphere, many mammals in this biome hibernate in the winter, while many bird species migrate to warmer climates. Humans have logged many temperate broadleaf forests around the world.Flora – deciduous trees that drop their leaves in winter Fauna – deer, wolves, bear, birds, small mammals TEMPERATE BROADLEAF FOREST Great Smoky Mountains National Park in North Carolina

Denali National Park, Alaska, in autumn Tundra covers large areas of the Arctic, up to 20% of the Earth’s land surface. Alpine tundra is found on high mountaintops at all latitudes, including the tropics. The plant communities in alpine and Arctic tundra are very similar. The Artic tundra winter is long and cold, while the summer is short and mild. The growing season is very short. Tundra vegetation is mostly herbaceous, consisting of a mixture of lichens, mosses, grasses, forbs, and dwarf shrubs and trees. A permanently frozen layer of permafrost prevents water infiltration and restricts root growth. Large grazing musk oxen are resident in Arctic tundra, while caribou and reindeer are migratory. Migratory birds use Arctic tundra extensively during the summer as nesting grounds. Arctic tundra is sparsely settled by humans but has recently become the focus of significant mineral and oil extraction.Flora – few if any, trees, grasses, wildflowers Fauna – lemmings, arctic foxes, snowy owls, caribou, reindeer TUNDRA Denali National Park, Alaska, in autumn