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