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ISC 201 Man and Environment

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1 ISC 201 Man and Environment
2.The Biosphere

2 The biosphere is the earth envelope – a thin realm composed of water, land and air …. where organisms are found, --- or a global ecosystem.    The largest communities on land are called biomes. ??????

3 Varying combinations of both biotic and abiotic factors
Abiotic and biotic factors influence the structure and dynamics of biomes Varying combinations of both biotic and abiotic factors Determine the nature of Earth’s many biomes Biomes Are the major types of ecological associations that occupy broad geographic regions of land or water

4 There is no equivalent term for large aquatic communities because both have unique, defined characteristics. ??????

5 Aquatic and terrestrial biomes
(Biome = major ecosystem type)

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7 - Temperate deciduous forest - Coniferous forest - Tundra
Terrestrial biomes:                         - Tropical forest                         - Savanna                         - Desert                         - Chaparral                         - Temperate grassland                         - Temperate deciduous forest                         - Coniferous forest                         - Tundra                 

8 Distribution of the Earth's eight major terrestrial biomes
Distribution of the Earth's eight major terrestrial biomes. (Adapted from: H.J. de Blij and P.O. Miller Physical Geography of the Global Environment. John Wiley, New York. Pp. 290.)

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10 Tropical rain forests or evergreen broadleaf forest:
The tropical rain forest is a forest of tall trees in a region of year-round warmth (mean temp. 25OC). An average of 50 to 260 inches (125 to 660 cm.) of rain falls yearly. Almost all rain forests lie near the equator. Evergreen trees produce new leaves and shed old ones through the year. TRF produce more litter than other forest biomes. It is the richest biome, both in different kinds of species found and total amount of living matter. The soil is highly weathered, humus poor, and not good nutrient reservoirs. WHY??

11 Rain forests belong to the tropical wet climate group.
Rainforests now cover less than 6% of Earth's land surface. Scientists estimate that more than half of all the world's plant and animal species live in tropical rain forests. Tropical rainforests produce 40% of Earth's oxygen. WHY??

12 Tropical Rainforest Tropical trees often have buttressed bases to help support their heavy above-ground biomass. Important Facts: -- Amazon rainforests produce about 40% of the world's oxygen -- One in four pharmaceuticals comes from a plant in the tropical rainforests rainforest plants are believed to offer cures for cancer -- 40% of tropical rainforests have already been lost in Latin America and Southeast Asia

13 Tropical Forest: Vertical stratification with trees in canopy blocking light to bottom strata. Many trees covered by epiphytes (plants that grow on other plants).

14 Tropical deciduous forest: many trees drop some or all of their leaves during a pronounced dry season.

15 Savanna Savannas or tropical savannas are grasslands with scattered drought-resistant trees that generally do not 10 meters in height. Tree and shrub species shed their leaves during dry season to reduce water loss. Savannas are characterized by distinct wet and dry seasons. Temperatures are hot all year long. Savannas support the richest diversity of grazing mammals in the world. They have many types of plants and animals. Fire is an important abiotic factor.

16 Tropical Savanna Savanna vegetation is typical composed of a mixture of grass and trees. (Source: NASA - Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) Net Primary Productivity (NPP) Database).

17 Giraffes are a common grazer on the African savanna.
Savannas are also home to a number of predator species who prey on grazing animals.

18 Savanna

19 Prairie is temperate grassland
Natural grassland ecosystems are dominated by various species of grass. The dominant animals are grazing and burrowing types. Grazing and periodic fires keep shrublands and trees from encroaching on the fringes of many grasslands.

20 Prairie is a temperate grassland.
Marked by seasonal drought and fires, and grazing by large animals. Rich habitat for agriculture, very little prairie exists in US today. Common in organic rich and black chernozemic soil, so most grassland ecosystems have been modified by humans to grow grain and other dryland crops. Chernozems are among the richest in nutrients and consequently the most fertile in the world.

21 Chaparral Dense, spiny, evergreen shrubs, mild rainy winters; long, hot, dry summers. Periodic fires, some plants require fire for seeds to germinate. This biome is sometimes also called Mediterranean Scrubland or sclerophyll forest.

22 The Desert: Land of Little Rain
Desert habitat devoid of vegetation. Plants are drought-tolerant (capable to survive without water for a long time). Lizards are quite common in desert habitats. Alarmingly, many parts of the world are undergoing desertification – the wholesale conversion of grassland and other productive biomes to dry wastelands.

23 Desert: Sparse rainfall (< 30 cm per year), plants and animals adapted for water storage and conservation. Can be either very, very hot, or very cold (e.g. Antarctica)

24 1000 year old Welwitschia plants survive the Namib desert by catching dew off the ocean currents

25 Temperate Deciduous Forest
The temperate forest biome is found in the middle latitudes around the globe and this biome is very seasonal. This biome is characterized by a moderate climate and deciduous trees. Temperatures become cold during winter. Decomposition is not as rapid as in the tropical rain forest, and nutrients are conserved in accumulated litter on the forest floor. This biome at one time, occupied northeastern North America, Europe, and eastern Asia. It has been very extensively affected by human activity, and much of it has been converted into agricultural fields or urban developments.

26 Temperate Deciduous Forest: Mid-latitudes with moderate climate, high rainfall ( cm/y), distinct vertical strata: trees, understory shrubs, herbaceous sub-stratum. Loss their leaves in the fall, many animals hibernate or migrate then. Original forests lost from North America by logging and clearing.

27 Boreal Coniferous Forest
Cold Climate Forests: The Taiga The understory of boreal forest habitats is usually poorly developed due to low light penetration. Taiga lies bet N latitude, climate is cool to cold, vegetation are needle leaf evergreen variety of tree species.

28 Coniferous forest (or Taiga): Largest terrestrial biome on earth, old growth forests rapidly disappearing, usually receives lots of moisture as rain or snow ( cm/y).

29 Bears are common in the boreal forest ecosystem.

30 Tundra The geographical distribution of tundra biome is poleward 60O N latitude. Characterized by an absence of trees, the presence of dwarf plants. Soil – permanently frozen (permafrost). The permafrost line is a physical barrier to plant root growth. Average temperatures in summer month is below 10o C. Tundra: Permafrost (Permanent frozen ground), bitter cold, high winds and thus no trees. Has 20% of land surface on earth.

31 The examination of Earth’s aquatic biomes
Tropic of Cancer Equator 30S Continental shelf Lakes Coral reefs Rivers Oceanic pelagic zone Estuaries Intertidal zone Abyssal zone (below oceanic pelagic zone) Key Tropic of Capricorn

32 Aquatic biomes Account for the largest part of the biosphere in terms of area Can contain fresh or salt water Oceans Cover about 75% of Earth’s surface Have an enormous impact on the biosphere

33 - Oceanic pelagic biome - Coral reefs - Benthos
 A.  Aquatic biomes cover about 75% of the earth’s surface                         - Wetlands                         - Lakes :- 2 Types of lake                         - Rivers, streams                         - Intertidal zones                         - Oceanic pelagic biome                         - Coral reefs                         - Benthos          

34 Freshwater Ecosystems
Lakes and Ponds - Standing Water Deep lakes contain three distinct zones, each with its characteristic communities of organisms.

35 Freshwater Ecosystems
Lakes and Ponds (Standing Water) Littoral zone The zone close to shore. Here light reaches all the way to the bottom. The producers are plants rooted to the bottom (like water lilies and cattails) and algae attached to the plants and to any other solid substrate. The consumers include -- tiny crustaceans -- flatworms -- insect larvae -- snails -- frogs, fish, and turtles.

36 Freshwater Ecosystems
Lakes and Ponds (Standing Water) Limnetic zone This is the layer of open water where photosynthesis can occur. As one descends deeper in the limnetic zone, the amount of light decreases until a depth is reached where the rate of photosynthesis becomes equal to the rate of respiration. At this level, net primary production no longer occurs.

37 Freshwater Ecosystems
Lakes and Ponds (Standing Water) Limnetic zone Life in the limnetic zone is dominated by:- floating microorganisms - called plankton actively swimming animals - called nekton. The producers in this ecosystem are phytoplankton (algae). The primary consumers include such animals as microscopic crustaceans and rotifers - the so-called zooplankton. The secondary (and higher) consumers are swimming insects and fish. These nekton usually move freely between the littoral and limnetic zones.

38 Freshwater Ecosystems
Lakes and Ponds (Standing Water) Profundal zone The dark bottom region This zone depends for its calories on the drifting down of organic matter from the littoral and limnetic zones. The profundal zone is chiefly inhabited by primary consumers that are either attached to or crawl along the sediments at the bottom of the lake, mainly insect larvae, scarvenger fishes. Such bottom-dwelling animals are called the benthos. The sediments underlying the profundal zone also support a large population of bacteria and fungi. The decomposers break down the organic matter reaching them, releasing inorganic nutrients for recycling.

39 Wetlands: includes marshes, bogs, swamps, seasonal ponds
Wetlands: includes marshes, bogs, swamps, seasonal ponds. Among richest biomes with respect to biodiversity and productivity. Very few now exist as they are thought of often as wastelands.

40 Lake:- 2 types Oligotrophic Lake: Nutrient poor, water is clear, oxygen rich; little productivity by algae, relatively deep with little surface area.

41 Lake:- 2 types Eutrophic lake: nutrient rich, lots of algal productivity so it’s oxygen poor at times, water is murkier  often a result of input of agricultural fertilizers

42 Rivers and Streams The habitats available in rivers and streams differ in several ways from those in lakes and ponds. Because of the current, the water is usually more oxygenated. Photosynthesizers play a minor role in the food chains here; a large fraction of the energy available for consumers is brought from the land; e.g., in falling leaves. Rivers and Streams: Organisms need adaptations so that they are not swept away by moving water; heavily affected by man changing the course of flow (E.g. dams and channel-straightening) and by using rivers to dispose of waste.

43 Saltwater Communities
Estuary: Place where freshwater stream or river merges with the ocean. Highly productive biome; important for fisheries and feeding places for water fowl. Often heavily polluted from river input so many fisheries are now lost.

44 Ocean Zones Marine environment with zonation.

45 Ocean Zones Ecologists classify ocean habitats and their organisms
on the basis of:- 1) water depth determines pelagic zone includes neritic zone and oceanic zone, 2) type of bottom determines intertidal, continental shelf and abyssal zones 3) and light level determines photic and aphotic zones.

46 Intertidal Zone: Alternately submerged and exposed by daily cycle of tides. Often polluted by oil that decreases biodiversity.

47 Coral Reefs: occur in neritic zones of warm, tropical water, dominated by cnidarians (corals); very productive, protect land from storms; most are now dying from rise in global temperatures

48 Deep-sea vent: Occurs in benthic zone; diverse, unusual organisms; energy comes not from light but from chemicals released from the magma.

49 Biomes Summary

50 Biomes A _______ is a large group of ecosystems that share the same kind of climax community. There are 2 Types of Biomes: 1. 2. biome Terrestrial Aquatic

51 Terrestrial Biomes Terrestrial biomes are biomes located on _____.
land Terrestrial biomes are biomes located on _____. All Terrestrial Biomes are based upon the various types of Climate Patterns. There are 6 Types of Terrestrial Biomes: 1. 2. 3. 4. 5. 6. Tundra Taiga Desert Grassland Deciduous Forest Tropical Rainforest

52 Aquatic Biomes Aquatic Biomes are those biomes located in bodies of ______. All Aquatic Biomes are based upon the salinity (saltiness) of the water. Also, the aquatic biomes takes up the most space on Earth. There are 3 Kinds of Aquatic Biomes: 1. 2. 3. water Marine: High Salinity Level (Saltwater) Estuary: Moderated Salinity Level (Mildly Salty) Freshwater: Little to No Salinity Levels at all

53 Tundra Tundra environments have extremely _____ weather.
The greatest precipitation is _____. Most animals respond to this environment by growing thick fur and the plants remain small (dwarf). The soil is __________, which is a layer of permanently frozen ground. cold snow permafrost

54 Taiga Taiga environments consist of long severe _______ & short, dry ________. Most animals adapt by _________ when it is cold, coming back when it is warm. There are many adaptable trees such as evergreen trees. winters summers migrating

55 Desert Desert environments are ____ & ____.
Animals adapt to this environment by constantly conserving (saving) ______ when it is needed for them most. Animals are usually nocturnal. Nocturnal animals are those that sleep during the ____, and come out at _____ when it is much cooler. hot dry water day night

56 Grassland Grasslands environments experience a ____ & ____ season.
Many animals in this are _______ animals. ________ animals are those that feed upon plants, grass, etc. The soil in this area is _____. wet dry grazing Grazing rich

57 Deciduous Forest Deciduous Forest environments have an abundant level of _________. They also have 4 distinct ______. Trees usually lose their leaves in the ______. This is also the Biome where WE LIVE! precipitation seasons winter

58 Tropical Rainforest Tropical Rain Forest environment is the _______ & _______ of all biomes. It is found in areas near the ________. Most life severely depends upon the _______ available. The forest area is characterized by _______. warmest wettest equator sunlight layers

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