aquatic biomes Flashcards
what are biomes?
biotic units that are classified by predominant plant types and animals correlated with regional climate patterns
what are the eight different biomes?
tropical forest
temperate forest
taiga (boreal forest)
temperate grasslands
tropical savanna
chaparral (shrublands)
tundra
desert
how are forest ecosystems characterized?
by a closed canopy of trees
how are woodland and savanna ecosystems characterized?
by the codominance of grasses and trees (or shrubs)
what are shrubs?
dominant form in shshrublands and grasses dominate in grasslands
what is a desert?
a general category used to describe the scarcity of plant cover in some areas
how is a biome defined?
- mean annual temperature
- mean annual precipitation
what influences a biome’s location?
Topography, soil type, and disturbance exposure
describe boundaries between biomes?
broad and can be indistinct
how is mean annual precipitation influenced?
Mean annual precipitation declines with decreasing mean annual temperature
how is a decrease in the range of environmental conditions defined?
by moisture availability going from the tropics to the temperate and arctic regions
Mean annual temperature decreases from the equator to the poles which means that seasonal variation (increases/decreases)
increases
the systematic latitudinal pattern of change in environmental conditions is a direct result of
seasonal variations and solar radiation influx
Adaptations of the relative contribution of three plant life-forms
- trees
- shrubs
- grasses
each exhibit fundamentally different patterns of carbon allocation and morphology
Deciduous 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
Winter-deciduous leaves
lost in response to low temperatures – seen in temperate regions
Drought-deciduous leaves
lost in response to dry conditions
leaf longevity of evergreens?
Evergreen leaves live beyond a year
Broadleaf evergreen leaf
characteristic of environments with no distinct growing season, where growth continues year-round
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
The production of a leaf has a “cost” to the plant
defined in terms of the carbon and other nutrients required to construct the leaf
what is the time required to pay back the cost of production
a function of the rate of net photosynthesis (carbon gain)
* Low rates of net photosynthesis = longer pay back time
what is the time required to pay back the cost of production
a function of the rate of net photosynthesis (carbon gain)
* Low rates of net photosynthesis = longer pay back time
what is the time required to pay back the cost of production
a function of the rate of net photosynthesis (carbon gain)
Low rates of net photosynthesis
= longer payback time
If the payback cost is greater than a single growing season
the plant cannot “afford” to have deciduous leaves
describe the needle lead evergreen and its payback capacity costs
a plant adapted for survival in an environment with a distinct growing season
* The plant has a limited ability to produce enough carbon during a single growing season to produce new leaves each year so keeps its leaves for multiple growing seasons
Broadleaf evergreen trees (tropical and subtropical rain forest)
no distinct seasonality
Drought-deciduous trees (seasonal tropical forests) –
distinct dry season
how are scrublands dominated?
Stature and density of trees decline, giving rise to woodlands, and savannas as conditions become drier, Trees can no longer be supported, giving rise to arid shrublands and desert.
Broadleaf evergreen trees
(wet tropics)
Winter-deciduous trees (temperate forests)
Areas with low precipitation cannot support trees and develop into grasslands (prairies)
Needle-leaf evergreen trees
(conifer forest or taiga)
Trees can no longer be supported, giving rise to tundra
shorter growing season and greater temperature extremes
The tropical rain forest
dominated by broadleaf evergreen plants
where do rainforests fall on equator?
Rain forests are restricted to the equatorial zone between 10°N and 10°S
what is the temperature and precipitation of a tropical rainforest?
Temperatures are warm throughout the year and rainfall occurs almost daily
* average temperature greater than 68°F
* average annual rainfall greater than 80 inches
what is the daylight of a tropical rain forest?
12 hours
what are the seasons of a tropical rain forest?
Seasons are either rainy or dry
fun facts about tropical rain forests
The Amazon basin of South America is the largest and most continuous rain forest in the world
* The second largest is in Southeast Asia
* The third largest is in West Africa
* Smaller rain forests are found along the northeastern coast of Australia, the windward side of the Hawaiian Islands, the South Pacific Island, the east coast of Madagascar, northern South America, and southern Central America
are tropical rainforests diverse?
Covering 6 percent of land surface, tropical rain forests account for more than 50 percent of known plant and animal species
what is the percentage of non human primates living in tropical rain forests?
90
what are the five vertical layers in a tropical rain forest?
- emergent trees
- upper canopy
- lower canopy
- shrub understory
- ground layer of herbs and ferns
Canopy is multilayered and continuous, and little light penetrates? why?
There is so much water.
what are plants found in a tropical rain forest?
- lianas (climbing vines)
- epiphytes
- strangler figs
how tall are trees in rainforests?
over 100 feet tall
what are buttresses?
function as prop roots in shallow soil that offers poor anchorage
what are the leaves like in a tropical rainforest?
Trees tend to have smooth bark, dark green, oval waxy leaves with narrowing tips at the apex
what is the floor of a tropical rainforest like?
The floor of a tropical rain forest is thickly laced with roots that form a dense mat on the ground
Soils of the tropical rain forests are poor yet support significant vegetation – oxisols, infertile, deeply weathered and severely leached. Why is this?
- majority of nutrients leached out by continuous rainfall
- no “upper” rich organic layer – leaf litter breaks down quickly by
decomposers - nutrients are “locked-up” in vegetation
- lack of sustainable agricultural practices
why do tropical rain forests have high rates of NPP and high annual rates of litter input to the forest floor?
- very little leaf litter accumulates because decomposers consume the dead organic matter almost as rapidly as it falls to the forest floor
- the average time for leaf litter to decompose is about 24 weeks
what are dry tropical forests?
regions with greater seasonality in precipitation. undergoes a dry season
* Length of this season is based on latitude
* The farther from the equator, the longer the dry season
what happen during the wet and dry season of dry tropical forests?
- During the dry season, drought-deciduous plants drop
their leaves - During the wet season, this biome is uniformly green
what is a savanna?
a range of vegetation types in the drier tropics and subtropics that are characterized by a ground cover of grasses with scattered shrubs or trees.
what is the temperature/ precipitation like in a savanna?
- Temperature ranges 68°F – 86°F
- Average annual rainfall is 20 – 25 inches
- Rainy season (6 – 8 months per year) followed by long periods of drought – potential for fires
what is the distribution of savanna vegetation controlled by (plant activity and productivity) ?
rainfall (seasonal precipitation)
what is the soil like in the savanna?
lassified as porous bedrock with good water drainage
* laterization (high in Fe & Al) is the dominant soil-forming process and low fertility oxisols can be expected
* Only a thin top layer of humus (organic) materials
* leaf litter decomposes in the rainy season
what is the two-layer vertical structure of the savannas?
- grasses – several inches to several feet
- trees or shrubs
what are some important characteristics of a savanna?
- occur on land surfaces of little relief
- fire-adapted vegetation
- woody vegetation is short-lived (only several decades)
Micro-environments with higher soil nutrients and moisture are found under tree canopies, what does this influence?
species distribution and diversity
what live in a savanna?
herbivores (invertebrate and vertebrate), insects, carnivores, and scavengers.
what are the environmental concerns from savannas?
result of overgrazing, land clearing for crops, and poaching
Natural grasslands occupy regions where rainfall is between…
10 and 30 inches
grasslands exist through the intervention of
fire and human activity. have shrunk to less than 12 percent.
where do grasslands occur?
in the mid-latitudes in mid-continental regions where annual precipitation is reduced as air masses move inland
Temperate Grasslands
- steppes and prairies
- further away from the equator
- covers interior of North America, Eurasia and South
America
Savanna – sometimes referred to as tropical grasslands
closer to the equator
Steppes
Ukraine eastward through Russia and Mongolia
* have short grasses – treeless
* hot summers – cold winters
* plants usually grow greater than 1 foot tall
what inhibit steppes?
Buffalo grass, cacti, sagebrush, speargrass, annual flowers
* Steppes animals include badgers, hawks, owls, snakes
* Steppes used to grow crops and graze livestock
what are some Enviromental issues due to usage of the grasslands?
- overgrazing – plowing – contaminated water
- wind blows loose soils especially after droughts
where do temperate grasslands exist?
- Great Plains of North America – Central Lowlands and High Plains of the US and Canada
- Pampas – Argentina, Uruguay, and southeastern Brazil
- Veld – Republic of South Africa
Prairies
-known for tall grass.
what is the temperature and precipitation of a prairie?
-20 to 35 inches of rainfall
-hot summers and cold winters. (100 to -40)
what are the soils like in a prairie?
Soils are deep and dark with a very fertile upper layer
* allows for many branched grass roots
* rotted roots hold soil together
what prevents wood shrubs and trees from “invading” and becoming established?
Seasonal droughts, fires, and large mammal grazing
what are some species in temperate grasslands?
*Grass species include purple needlegrass, blue grama, buffalo grass, and galleta
* Flowers more abundant – asters, blazing stars, golden rods, sunflowers, clovers, psoraleas, and indigos
what dominates grasslands?
- insects
- large grazing ungulates
- burrowing mammals
what are some characteristics of North American grasslands?
- bison, pronghorn antelope, prairie dogs, gophers,
mound-building harvester ants - helped develop and maintain the ecological structure of the shortgrass prairie
- many insects and spiders
- birds
what evolves grasslands to primary production?
grazing
what are the major consumers in grassland ecosystems?
invertebrates
what are the major consumers in grasslands (underground)
(nematodes are the dominant herbivores)
what are the three strata in a grassland
1) tall, green, ephemeral herbaceous growth
2) ground layer
3) belowground root layer
what does the herbaceous growth arise from?
arises from crowns, nodes, and rosettes of ground-hugging
plants
describe the below ground root layer
- can make up more than half of the plant biomass
- extends fairly deep into the soil
what are the environmental issues in temperate grasslands?
- turned into farms for crop production
- turned into grazing lands for livestock production
why have the grasslands been changed?
the grasslands are flat, few trees, covered with grass, and the soil is excellent with significant nutrients
how much of the world do deserts occupy?
The arid regions of the world occupy 25 to 35 percent of Earth’s landmass
where do deserts lie?
between 15 and 30 degrees
where do temperate deserts lie?
in the rain shadow of mountain barriers or are located far inland
Most of the arid environments are found in the Northern Hemisphere
- The Sahara in North Africa is the world’s largest desert (3 million square miles)
- Temperate deserts of Central Asia (Gobi Desert)
- Temperate deserts of western North America (Mohave and
Sonoran)
what are the deserts in the Southern Hemisphere are influenced by
cold ocean currents contribute to arid coastal regions, especially along the coasts of Chile and Peru
where are southern deserts located?
- The deserts of southern Africa include three regions: Namib
Desert, Karoo, Kalahari Desert - Forty percent of Australia’s land is classified as desert
what is the range of annual temperature in the desert?
Typical annual temperatures range between 68°F – 78° F
what do desert little cloud covers cause?
heat quickly radiates at night and it becomes cold
describe desert rainfall (less than 10 inches)
- rainfall concentrate in bursts between long no rain
periods
what is Virga
rainfall many times does not reach the ground
how do groups of associated species differ in response to differences in?
moisture – temperature – characteristics
soil tends to have lot of nutrients in the desert.
but water is needed to be productive
* little organic matter
* Soils are coarse-textured, shallow, gravely with excellent drainage but no subsurface water
* Find sand and dust are blown away leaving large particles – wind erosion
plant coverage in the desert
Plant covers in dry deserts is less than 10% but in semiarid deserts ranges up to 30%
Southwestern North American deserts (Mojave, Sonoran, Chihuahuan)
- bur sage and creosote bush
- Acacia, saguaro, palo verde, ocotillo, yucca, and ephemeral plants
Drought evasion
organisms do not reproduce or are inactive during the dry season
describe the flowering process in the desert
Plants flower only when moisture is present and persist as seeds during drought periods
* sprout, flower, and produce seeds when moisture and temperature are favorable
Animals adopt an annual cycle of activities or go into a dormant state (estivation)
Spadefoot toad (Scaphiopus) remains underground except to reproduce during rainy periods
Basic forms of plant life in the desert
- annuals
- succulents
- shrubs
describe the formation of plants in the desert
- Plants are typically ground-hugging shrubs and woody trees
- Leaves are small, thick with thick cuticle
- Cacti leaves become spines – photosynthetic activity is now in stems
how might plants in the desert be drought resistant?
- Desert plants may be deep-rooted woody shrubs such as mesquite, with a taproot that reaches the water table, making them independent from rainfall
- Other plants may have shallow roots that extend no more than a few centimeters below the surface (cacti), enabling a quick uptake of water when it is available
how have plants adapted to low water/moisture conditions?
- Some plants open their stomata only at night when evaporation is low
- Spines or aromatic odors to discourage herbivores looking for water
- More space between plants because roots are longer seeking water
- Water conservation occurs through the production of many small seeds
what kind of nocturnal life makes up ecosystem of a desert?
- insects: beetles, ants, locusts
- reptiles: lizards, snakes
- birds
- mammals
- Tend to be nocturnal
- Stay in protected areas during the day and come out at dusk to night to forage because it is cooler
Describe the mammals in the desert
mainly herbivores that graze and are generalists/opportunist.
given an example of grazing herbivores in the desert
Desert rodents (and ants) feed mostly on seeds
* Can eat up to 90 percent of the available seeds, affecting plant composition and plant populations
* Some carnivores (foxes, coyotes) have mixed diets that include leaves and fruits
what is a shrubland? chaparral
a plant community in which the shrub growth is dominant or codominant
what is a shrub
A shrub is a plant with multiple woody, persistent stems (no central trunk) and a height from 12 to 25 feet
chaparral biome
composed of coastal sage shrub and inland foothill chaparrals (composed of hard woody plants)
what dominates Mediterranean ecosystems?
evergreen shrubs and sclerophyllous trees found along the western margins of the continents between 30° and 40° latitude
what are the five regions of shrublands?
- western North America
- borders of the Mediterranean Sea * central Chile
- cape region of South Africa
- southwestern/southern Australia
A mediterranean climate has
- hot, dry summers with at least one month of protracted drought
- cool, moist winters
Areas with a mediterranean climate support similar-looking plant communities
- xeric broadleaf evergreen shrubs * dwarf trees
- herbaceous understory
what are Sclerophyllous vegetation’s adaptations that allows it to reduce water loss during the summer period?
- small leaves, thickened cuticles, glandular hairs, sunken stomata
and shares adaptations to fire and low nutrient levels
what do Mediterranean scrublands lack?
an understory and ground litter and are highly flammable due to highly flammable oils.
what happens to chaparral in the fire?
Without fire, the chaparral grows taller and denser, and a large fuel load of leaves and twigs builds up and sets the stage for fire
* After fire, the land returns to either lush green sprouts from buried root crowns or grass
how are shrubland soil?
generally deficient in nutrients
* limited litter decomposition as a result of low winter temperatures
* low soil moisture in summer months
* Shrubland soils- Alfisols – contain clays and “Al” + “Fe”
how are forests characterized?
Climatic conditions of the humid mid-latitude regions give rise to the forests dominated by broadleaf deciduous trees in the Southern Hemisphere.
how is climate defined in a temperate forest?
- Temperate forests annual temperatures range from -20° F to 85°F
- Annual rainfall is 30 – 60 inches occurring equally throughout the year
- Seasons are well defined
- Climate is moderate and plants grow 140 – 200
days/year with 4 – 6 months frost free
how is soil defined in a temperate forest setting?
fertile and enriched with decaying leaf litter – ultisols replace alfisols soils
describe the canopy of a temperate forest?
Canopy is not dense allowing light penetration
* rich understory development & stratification of animals
Eastern North America deciduous forest
- mixed mesophytic forest (Appalachian plateau)
- beech–maple and northern hardwood forests (northern regions)
- maple–basswood forests (Great Lakes states)
- oak–chestnut (now oak) or central hardwood forests
(Appalachian Mountains) - magnolia–oak forests (Gulf Coast states)
- oak–hickory forests (Ozarks)
the end of the growing season in the broadleaf deciduous forests in temperate regions is marked by
the autumn colors of foliage before the leaves drop
After the winter, trees resume growth in the spring
in response to increasing temperature and longer day length. During this time, herbaceous species flower at this time, before the developing canopy leads to more dense shade
What are the four vertical layers in a temperate forest?
- upper canopy consisting of the dominant tree species * lower tree canopy or understory
- shrub layer
- ground layer of herbs, ferns, and mosses
where does the highest diversity in the forest occurs
on and just below the ground layer
Taiga or Conifer/Boreal forest
ound primarily in a broad circumpolar belt across the Northern Hemisphere and on mountain ranges
climate of taiga
Temperatures -58°F – 70°F limit the growing season
to a few months each year
* dominated by needle-leaf evergreen trees
* Precipitation is primarily snow and is 12 – 30 inches per year
soil in taiga
Soil is thin, nutrient-poor, and acidic
seasons of taiga
Seasons are divided into short, moist, and moderately warm summers – very long, cold and dry winters
growing season of taiga
- The length of the growing season in these boreal forests is 130 days
- Canopy permits low light penetration resulting in a limited understory
- Plants are dominated by cold-tolerant evergreen conifers with needle-like leaves
boreal forest (or taiga)
the largest expanse of conifer forest
The taiga encompasses the high latitudes of the Northern Hemisphere and covers 11 percent of the Earth’s terrestrial surface
The taiga primarily occupies formerly glaciated land and is a region of spruce, pine, lichens, moss, cold lakes, bogs, rivers, and alder thickets
The taiga is divided into three vegetation or latitudinal zones
-Forest-tundra ecotone
* open stands of stunted spruce, lichens, and moss
-Open lichen woodland
* stands of lichens and black spruce
-Main boreal forest (grades into the temperate forest)
* continuous stands of spruce and pine broken by poplar and birch on disturbed areas
Permafrost
perennially frozen subsurface that develops where the ground temperatures remain below 32°F for extended periods
Because the permafrost is impervious to water, it forces all water to remain and move above it, as a result
the ground stays soggy even though precipitation is low, allowing plants to exists in the driest areas
Boreal species, both broadleaf trees and conifers, are well adapted to fire, but suffer from
deforestation
boreal forest has a unique animal community
herbivores include caribou, moose, snowshoe hare, red squirrels, and porcupine
* predators include wolf, lynx, pine martin, and owls
* Nesting location for migratory neotropical birds
* Habitat of northern seed-eating birds
* Many herbivorous insects, including the spruce budworm
* food item for insectivorous birds in the summer
* outbreaks can defoliate and kill large areas of forest
tundra
a frozen plain that is located at the highest latitudes of the Northern Hemisphere encircling the North Pole. There are two broad types:
two types of tundra
- Tundra has up to 100 percent plant cover and wet to moist soils
- Polar desert has less than 5 percent plant cover and dry soil
tundra climate
The arctic area is known for its bitter cold and desert-like conditions
* Winter temperature average -30°F
* Summer temperature ranges from 37°F – 55°F
* enables this biome to sustain life
* Rainfall is low averaging 6 to 10 inches including
melting snow
tundra growing season
The growth season is short at 50 – 60 days
tundra vegetation
grows close to the ground and is composed of slow-growing lichens, mosses, grasses, sedges, and shrubs
Anaerobic conditions lead to what?
slow nutrient cycling
* Organic matter does not completely decompose but accumulates in thick layers referred to as peat
The alternate freezing and thawing of the upper layer of soil pushes stones and other material upward and outward from the mass to form
patterns surfaces like frost hummocks, frost boils, earth stripes, stone polygons.
Solifluction terraces (flowing soil)
form on sloping ground
creep, frost thrusting, downward flow of supersaturated soil over the permafrost
Solifluction terraces (flowing soil)
form on sloping ground
creep, frost thrusting, downward flow of supersaturated soil over the permafrost
Tundra plants are photosynthetically active about two months out of the year
- they maximize the growing season and light by photosynthesizing during the 24-hour daylight period
- erect leaves of some plants allow for almost complete interception of low-angle solar radiation
Tundra plants are photosynthetically active about two months out of the year
- they maximize the growing season and light by photosynthesizing during the 24-hour daylight period
- erect leaves of some plants allow for almost complete interception of low-angle solar radiation
what happens when most photosynthate goes to production of new growth until about a month before the season ends
resources are allocated only to roots; nutrients are moved from leaves to roots and belowground biomass
Most of the tundra vegetation is underground
root-to-shoot ratios range from 3:1 to 10:1
animal diversity in the tundra
Animal species diversity in the tundra is low but diverse
Invertebrates are concentrated near the surface
* segmented whiteworms, collembolas, and flies
Dominant vertebrates are herbivores
* caribou, lemmings, Arctic hare, musk oxen
* few herbivorous birds (ptarmigan, migratory geese)
Carnivores
* wolves, Arctic fox, weasels, snowy owls, jaegers, and other birds, including insect-eating waterfowl
Animals are adapted to withstand long, harsh, cold winters because
they breed and raise young quickly in the summer
adaptations of tundra animals
Animals have additional insulation from fat
* mammals and birds
* Animals hibernate during winter because food is not
abundant
* Or animals may migrate south
* birds and whales
* Reptiles and amphibians are few to absent because of cold
temperature (ectotherms)
