Ecology Chapter 23

What are the five vertical layers that a tropical rain forests?

1. emergent trees 2. upper canopy 3. lower canopy 4. shrub understory 5. Ground layer of herbs and ferns

what are the two-layer vertical structures of savannas?

1. grasses 2. trees or shrubs

What are thtree reasons that grasslands exist?

1. intervention of fire 2. human activity 3. selective pressure of grazing

The distribution of terrestrial ecosystems is influenced by

1. mean annual temperature and precipitation (Whittaker's graph, Fig. 23.2) 2. seasonality of temperature and precipitation 3. topography (mountains and valleys)

what is the distribution of savanna vegetation controlled by?

1. moisture 2. rainfall (amount and distribution) 3. soil texture, structure, water-holding capacity

What are the characteristics of a savanna?

1. occur on land surfaces of little relief 2. fire-adapted vegetation 3. woody vegetation is short-lived (only several decades)

What three forces interact to form the Arctic tundra?

1. permanently frozen deep layer of permafrost 2. overlaying active layer of organic matter and mineral soil that thaws each summer and freezes in winter 3. vegetation that reduces warming and retards thawing in summer

Thick ______ is not found in deserts because there are fewer plants than in more ______ climates.

1. soil 2. humid

what are the three strata in a grassland?

1. tall, green, ephemeral herbaceous growth 2. ground layer 3. below ground root layer

Rain forests are restricted to the equatorial zone between ______

10 N and 10 S

what is the average time for leaf litter to decompose?

24 weeks

Natural grasslands occupy regions where rainfall is between ______ per year, but they are not exclusively climatic

25 and 80 cm

Temperatures are warm throughout the year and rainfall occurs almost daily. what is the: mean temperature? precipitation?

>18C minimum monthly > 60 mm

______(tropical and subtropical rain forest) - no distinct seasonality

Broadleaf evergreen trees

what trees are in the wet tropics?

Broadleaf evergreen trees

______ are found primarily in a broad circumpolar belt across the Northern Hemisphere and on mountain ranges

Conifer forests

______ leaves are lost in response to dry conditions

Drought-deciduous

______(seasonal tropical forests) - distinct dry season

Drought-deciduous trees

______ leaves live beyond a year

Evergreen

what trees are in the conifer forest or taiga?

Needle-leaf evergreen trees

What is the primary difference between savannas and tropical forests?

Savannas have less precipitation.

When one examines the global distribution of tundra ecosystems, there are inconsistencies with the expected latitudinal distribution of the tundra biome. In South America there is a thin strip where these biomes are found from close to the equator almost to the southern tip of the continent. How are these found in these very different latitudes?

The line observed on the map corresponds to the Andes, a very tall mountain range.

What adaptations do the plants and animals have in these deserts to obtain water?

They have the capacity to store up to 5 tons of water The ability to expand Long needles help collect water They have to survive on limited water Some bats feed on nectar—a good source of water

why doesn't leaf litter accumulate?

Very little leaf litter accumulates because decomposers consume the dead organic matter almost as rapidly as it falls to the forest floor

what trees are in the temperate forests?

Winter-deciduous trees

Which of the following statements about organisms found in deserts is FALSE? a. Animals of the desert attempt to reproduce each year regardless of the amount of precipitation. b. Seed-eating animals in deserts may consume up to 90 percent of seed production. c. Desert plants tend to have either very deep or very shallow roots. d. Plants and animals of the desert must have adaptations to either resist or avoid water shortages. e. Seeds of some desert plants may only germinate when there is ample water.

a.

Which of the following statements about the tundra is FALSE? a. Tundra plants allocate far less energy to belowground biomass than do temperate species. b. Plants in the tundra photosynthesize 24 hours a day during the peak of summer. c. The leaves of tundra plants are nearly erect. d. Lemmings consume a greater biomass of plants in the tundra than do caribou. e. Tundra plants rarely grow taller than 30 cm.

a.

Which of the following statements is FALSE? a. Fires are relatively common in the taiga. b. Net primary productivity of boreal forests is greater than more-temperate forests. c. There is a relatively large accumulation of organic matter in soils of boreal forests. d. Permafrost does not allow water to penetrate, so the upper soils of the taiga are soggy. e. Boreal forests in North America and Siberia are being clear-cut to satisfy timber demand.

b.

Which of the following statements is FALSE? a. Needle-leaf evergreen trees tend to be found where nutrients are limited and leaf production is costly. b. Deciduous leaves are found only in areas with freezing winters. c. Broadleaf evergreen trees are found in areas with no distinct growing season. d. Trees decline in density and stature as conditions become more adverse for photosynthesis. e. Deciduous leaves are those that live for only a single year or growing season.

b.

what is a biome?

biotic units that are classified by predominant plant types

The ______ is the largest expanse of conifer forest

boreal forest (or taiga)

The tropical rain forest is dominated by ______ (tree)

broadleaf evergreen plants

Which of the following statements about deserts is FALSE? a. Deserts may experience cool or even freezing conditions. b. Temperate deserts are found far inland or in rain shadows of mountains. c. More deserts are found in the Southern Hemisphere than in the Northern Hemisphere. d. The major characteristic of deserts is low precipitation. e. Tropical deserts are influenced by the climatic patterns that result to the north and south of the intertropical convergence zone.

c.

Which of the following statements about the habitats of temperate climates is FALSE? a. Animal diversity is tied to vertical strata of temperate forests. b. Deciduous forests show vertical stratification. c. Herbaceous species of the temperate forests tend to flower just after the canopy regrows in the spring. d. Broadleaf deciduous forests dominate large portions of the humid regions of the temperate zone, especially in the Northern Hemisphere. e. In the Southern Hemisphere, temperate evergreen forests predominate in mild, moist climates.

c.

Needle-leaf evergreen leaf

characteristic of environments where the growing season is very short (higher latitudes) or nutrient availability severely constrains photosynthesis and plant growth

Broadleaf evergreen leaf

characteristic of environments with no distinct growing season, where growth continues year-round

the root system in grassland plants is ______

close to the soil and gathers rainfall quickly.

Forest ecosystems are characterized by a ______

closed canopy of trees

Woodland and savanna ecosystems are characterized by the ______

codominance of grasses and trees (or shrubs)

Which of the following statements about temperate grasslands is true? a. Ungulates are the dominant grazers of Australian grasslands. b. The temperate grasslands of Africa are called steppes. c. Grasslands thrive where temperatures are highest. d. The vegetation of temperate grasslands depends on the predictability and amount of rainfall. e. Grasslands of North America are divided into only two types.

d.

________ leaves live for only a single year or growing season; are shed at the end of a growing season and regrown at the beginning of the next

deciduous

what is a climate diagram?

describes the local climate at a specific location can be used to compare and contrast the climate at different locations around the world

This is the driest biome, where many plants have water-conserving features such as thick leaves and needles

desert

Many ______ lie between 15 and 30 latitude in response to the effect of the Intertropical Convergence Zone (ITCZ)

deserts

Which of the following statements about tropical savannas is FALSE? a. Temperature has a relatively small impact on the vegetation present in savannas. b. Water availability limits the density of woody plants. c. Savannas are characterized by grasses and occasional shrubs or trees. d. The dominant vegetation is fire-adapted in savannas. e. Savannas show little interannual variation in total precipitation.

e.

A high rate of ______ is often characteristic of a climate where there is not a steady flow of water and there are high temperatures.

evaporation

How do the deserts in Chile and the U.S. differ in their source of water?

fog

What are the 7 biomes we are studying this unit?

forest - tropical, temperate, and conifer (taiga or boreal forest) temperate grasslands tropical savanna tundra desert

Tropical rain forests have high rates of NPP and high annual rates of litter input to the ______

forest floor

Climatic conditions of the humid midlatitude regions give rise to the ______ dominated by broadleaf deciduous trees

forests

Which plant allocates the greatest amount of biomass to photosynthetic tissue and the least amount to supportive tissue?

grasses

what characterizes the tundra?

has up to 100 percent plant cover and wet to moist soils

Savannas support a large diversity of ______ that graze or browse on the vegetation

herbivores (invertebrate and vertebrate)

In tropical rain forests, high precipitation and consistently high temperatures result in __________.

high rates of decomposition and nutrient cycling

grasses maintain a ______ proportion of biomass in photosynthetic tissue (leaves) because little energy is required for support tissues (stems)

higher

Whittaker's graphical analysis of terrestrial biomes incorporates gradients of __________.

mean annual precipitation and mean annual temperature

what trees dominate the conifer forests?

needle-leaf evergreen trees

what is a drought evasion?

organisms do not reproduce or are inactive during the dry season

what is drought resistance?

organisms have adaptations that make them less susceptible to dry conditions

Areas with low precipitation cannot support trees and develop into grasslands. what is this called?

prairies

Temperate deserts lie in the ______ of mountain barriers or are located far inland

rain shadow

A ______ describes a range of vegetation types in the drier tropics and subtropics

savanna

In this hot, dry biome, populations of zebras, gazelles, and giraffes are concentrated around widely spaced watering holes

savanna

Regions where the climate is ______ are known as steppe

semiarid

The vegetation of tundra is dominated by

short plants such as sedges, heaths, and willow.

Trees can no longer be supported, giving rise to arid ______ and ______

shrublands and desert

A desert has a drier climate than a ______.

steppe

The ______ primarily occupies formerly glaciated land and is a region of spruce, pine, lichens, moss, cold lakes, bogs, rivers, and alder thickets

taiga

The______ encompasses the high latitudes of the Northern Hemisphere and covers 11 percent of the Earth's terrestrial surface

taiga

This biome is characterized by broad-leaved trees that lose their leaves each fall and remain dormant during winter

temperate deciduous forest

Also called steppe or prairie, this biome has been extensively developed for agricultural use due to its nutrient-rich soils

temperate grassland

in conifer forests, low ______ limit the growing season to a few months each year

temperatures

What is permafrost?

the perennially frozen subsurface that develops where the ground temperatures remain below 0C for extended periods

What can influence the occurrence of a biome in a location?

topography, soil type, disturbance exposure, precipitation, and temperature

Despite having lush vegetation and diverse biological communities, the soil in this biome has low nutrient content and cannot support long-term agriculture

tropical rainforest

The______ is a frozen plain that is located at the highest latitudes of the Northern Hemisphere

tundra

This cold, dry biome is populated by lichens and shrubs that can survive great seasonal variations in sunlight and temperature

tundra

Trees can no longer be supported, giving rise to ______

tundra

what is estivation?

when animals adopt an annual cycle of activities or go into a dormant state

______ leaves are lost in response to low temperatures - seen in temperate regions

winter-deciduous

Stature and density of trees decline, giving rise to ______ and ______ as conditions become drier

woodlands and savannas