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large biological communities shaped by the physical environment, particularly climatic variation based on morphological similarities, not taxonomic.
Evolution of similar growth forms among distantly related species in response to similar selection pressures.
The Biosphere occurs between
(zone of life) occurs between the lithosphere and the troposhere.
Biomes are based on
similarities in the morphological responses of organisms to the physical environment, not on taxonomic similarities.
Terrestrial biomes are classified by
the growth form of the most abundant plants?
Selection pressures of the terrestrial environment include ----- ------------- ------- --------- ----------
aridity, high and subfreezing temperatures, intense solar radiation, grazing by terrestrial animals, and crowding by neighbors.
which biome is most often used as farm land
temperate decidious forest
Land use change:
Conversion of land to agriculture, logging, resource extraction, urban development.The potential and actual distributions of biomes are markedly different. Human influence
Wet and dry seasons in Tropical seasonal forests and savanahs associated with
movement of the Intertropical Convergence Zone
Tropical rainforests are disappearing rapidly due to --------
About-----------of the tropical rainforest biome has been altered.
- logging and conversion to pasture and croplands.
-------- is an important factor in
Tropical seasonal forests and savanahs
Tropical seasonal forests and savanahs have
Shorter trees, deciduous in dry seasons, more grasses and shrubs.
hot deserts are located at
Associated with high pressure zones around 30° N and S.
Hot deserts have
- High temperatures, low water availability
- Sparse vegetation and animal populations
Plants in hot deserts exhibit
Many plants exhibit stem succulence—cacti in the Western Hemisphere, euphorbs in the Eastern Hemisphere
temperate grassland located at
Between 30° and 50° latitude
Temperate grassland threats
- Most converted to agriculture
- Threats from habitat alteration and desalinization
Temperate grassland weather and landscape
- Seasonal temperature variation—warm, moist summers and cold, dry winters
- Grasses dominate; maintained by frequent fires and large herbivores such as bison
temporate shrublands and woodlands location
Mediterranean-type climates—west coasts of the Americas, Africa, Australia, and Europe, between 30°–40° N and S.
temporate shrublands and woodlands climate
Wet season in winter; hot, dry summers.
temporate shrublands and woodlands threats
Conversion to viticulture and urbanization threats
temporate shrublands and woodlands landscape
Vegetation is evergreen shrubs and trees.Fire is a common an important feature.
the normal development of much sclerenchyma in the leaves of certain plants, as some desert plants, resulting in thickened, hardened foliage that resists loss of moisture.
Temporate Evergreen forest threats
- Threats from logging
- Very little old-growth temperate evergreen forest remains.Fire suppression is a threat.
Temporate Evergreen forest location
At 30° to 50° N and S, in coastal and maritime zones.
Temporate Evergreen forest landscape
- Leaves tend to be acidic, and soils nutrient-poor.
- Temperate rainforests receive 50–400 cm rain per year.
Temporate Evergreen forest diversity
Lower diversity than tropical and deciduous forests
Boreal Forests location
Between 50° and 65° N.
Boreal Forests climate and plants
- Long, severe winters
- Permafrost (subsurface soil that remains frozen year-round) impedes drainage and causes soils to be saturated
- Trees are conifers—pines, spruces, larches
Boreal Forests soil
High organic matter soils; low decomposition=peat bogs
Boreal Forests threats
- Logging, oil and gas development
- Climate warming may result in release of carbon stored in boreal soils, creating a positive feedback to warming.
Above 65° latitude, mostly in the Arctic
Tundra climate and seasons
- Cold temperatures, low precipitation
- Short summer with long days
Tundra soil and life
- Vegetation is sedges, forbs, grasses, low-growing shrubs, lichens, and mosses
- Permafrost is widespread
- Not as much human settlement; more pristine
- Loss of predators
- Global change
On mountains, ------------ and --------- change with elevation, resulting in-----------
- temperature and precipitation
- bands of biotic assemblages similar to biomes.
- There are also smaller scale variations associated with slope aspect, proximity to streams, and prevailing winds.
Biological zones in freshwater systems are associated with the ----------- (5) of the water.
velocity, depth, temperature, clarity, and chemistry of the water.
Freshwater streams and lakes are a key connection between
terrestrial and marine ecosystems.They process inputs of chemical elements and energy from terrestrial systems and transport them to the oceans.
Open water; dominated by plankton (small and microscopic organisms suspended in the water).Photosynthetic plankton (phytoplankton) are limited to the upper layers through which light penetrates (photic zone).
Marine biological zones are determined by ocean depth,
light availability, and the stability of the bottom substratum.
Oceans cover -------- of Earth’s surface and contain a
- rich diversity of unique biota.
Marine zone are categorized by
depth and relationship to shorelines.
Salt marshes are ---------- dominated by---------
- shallow coastal wetlands
- emergent plants such as grasses and rushes.
Plants occur in zones that --------that result from --------. The highest zone is ------------.
- reflect salinity gradients
- periodic flooding at high tide
- most saline (gets least flooding)
In North America, the last continental glaciers were receding about 13,000 years ago, and the Great Plains supported a high diversity of
megafauna:Woolly mammoths and mastodons, several species of horses, camels, giant ground sloths, saber-toothed cats, cheetahs, lions, and giant short-faced bears.
About ----------years ago, many of the large mammals of North America went extinct.
temperate decidious forests
- Occur at 30° to 50° N, on continental edges, in areas with rainfall to support tree growth
- Leaves are dropped during winter.
- Oaks, maples, and beeches occur everywhere in this biome.
- Species diversity lower than tropical rainforests
-------- organisms are bottom dwellers, and include many kinds of invertebrates.
Some benthic organisms feed on ------------ (dead organic matter), others are predators.
Some benthic organisms live in the hyporheic zone—the -----------------------------------------------------------
substratum below and adjacent to the stream, where there is water movement from the stream or from groundwater.
Human effects on streams include (6)
- pollution sediment inputs,
- introduced species.
- disposal of sewage and industrial wastes (toxic levels)
- Excessive fertilizer use
- Deforestation increases sedimentation
- Dam construction and channelization
Lakes and still waters (lentic) occur ------------------- Lakes can be formed by -----------, from -----------, in ----------, in -----------, or by ---------------
- where depressions in the landscape fill with water.
- glacial processes
- river oxbows
- volcanic craters
- tectonic basins
- animal activities, including humans and beavers.
Marine zones next to continents are influenced by the ------- and ---------
tides and wave action.
Tides are generated by the ---------- between -----------------
- gravitational attraction
- Earth and the moon and sun
The magnitude of tidal ranges varies by ------------- and is related to ----------- and ------------
- shoreline morphology
- ocean bottom structure
The open ocean beyond the continental shelves is called the
The -----------, which supports the highest densities of organisms, extends ------------
- photic zone
- to about 200 m depth.
Below the photic zone, energy is supplied by
Estuaries occur at the junctions of ----------
-----------also bring terrestrial sediments and nutrients, contributing to the productivity of estuaries.
Salinity varies as -------------
fresh water flows in from the river and salt water flows in from the sea.
The Rocky intertidal zone environment alternates between
marine and terrestrial with the rise and fall of the tides.
Bands of organisms result in the rocky intertidal zone, depending on
their tolerance to drying, salinity, temperature, and interactions with other organisms.
Sandy Shores location, trends, life
- Long Island, Bahamas
- low food, high wave energy
- invertebrates (clams, sea worms, and mole crabs, polychaete worms, hydroids, and copepods), few vascular plants, vertebrates
Shallow Ocean Zones allow------------
light to penetrate to the bottom and support photosynthetic organisms that support other organisms.
Coral reefs are restricted to----------- .Corals are related to , form -----------, and have associated -----------
- large colonies
- algal partners.
Many corals extract -------------- from seawater to build a --------------
- calcium carbonate
- skeleton-like structure that over time, forms large reefs
Although coral reefs grow slowly, over millions of years, corals have constructed------------.Rates of production of biomass are some of the highest in the world.
thousands of kilometers of coastline and many islands
Coral reefs support up to a------------, the highest diversity on Earth.---------------rely on coral reefs for habitat
million species of organisms
economically important fishes
Coral reef dangers (5)
- Sediments carried by rivers can cover and kill the corals
- Excess nutrients increase the growth of algae on the surface of the corals
- Warming ocean temperatures can result in the loss of the algal partners from the corals, resulting in coral bleaching.
- Increased incidence of fungal infections may be related to increased dust associated with desertification.
- Future changes in ocean chemistry may inhibit the ability of corals to form skeletons.
The seaweed ------------ has gas-filled bladders to keep it afloat. It forms large floating islands that are habitat for other organisms.
Organisms in the pelagic zone must have ways to prevent
sinking out of the photic zone, such as swimming.
Below the photic zone, (Temp and pressure)
temperatures drop and pressure increases.
Crustaceans such as copepods graze on the
rain of falling detritus from the photic zone.
(3) are the predators of the deep sea.
Crustaceans, cephalopods, and fishes
Ocean bottoms (--------) are sparsely populated, with -----------------(temp and pressure)
- (benthic zone)
- temperatures near freezing, and very high pressure.
Benthic zone sediments are rich in --------, contain ----------. Sea stars and sea cucumbers graze the ocean floor or filter food from the water. ----------- is also used by benthic predators to lure prey.
- organic matter, contain bacteria, protists, and sea worms.
over kill hypothesis
The “overkill hypothesis” has received increasing support such as
- Archeological evidence shows that humans butchered some of these extinct animals.On small islands, human arrival and extinctions coincided.
- Humans also brought diseases as well as predators such as rats and snakes.
- Other mechanisms -spread of diseases by humans and dogs, climate change, and the loss of some species that depended on others, such as mastodons.
Between 1700 and 1900, human activities caused profound changes, one being the Spanish introduction of --------.
Horses , facilitating bison hunting.Arrival of Euro-Americans and their conflicts with Native Americans led to the near extinction of bison.
Humans began to use more ------------- to manage habitat and for small-scale agriculture between 1700 and 1900
After 1850, ------ and ------------ transformed the landscape.
mechanized agriculture and domesticated animals
Today only ------------ of the eastern tall grass prairie remains.----------- and ------------practices led to the “Dust Bowl” of the 1930s. Drought and windstorms resulted in substantial losses of ------------
- Overgrazing and unsustainable agricultural
- fertile topsoil.