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CHAPTER 4: Ecosystems & Communities

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1 CHAPTER 4: Ecosystems & Communities
4-1 The Role of Climate 4-2 What Shapes an Ecosystem 4-3 & 4-4 Biomes

2 California State Standards
Students know how to analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of nonnative species, or changes in population size. Stability in an ecosystem is a balance between competing effects. Students know biodiversity is the sum total of different kinds of organisms and is affected by alterations of habitats.

3 4-1 The Role of Climate Objectives Identify the causes of climate.
Explain how Earth’s temperature range is maintained. Identify Earth’s three main climate zones.

4 4-1 The Role of Climate I. Weather vs. Climate
A. Weather is the of Earth’s atmosphere at a particular time and place. B. Climate refers to the average, of temperature and precipitation in a particular region. Climate is determined by: 1. 2. Transport of heat by 3. Shape and elevation of day-to-day condition year-after-year conditions Latitude winds and ocean currents landmasses

5 Unequal Heating of the Earth
Sunlight Most direct sunlight 90°N North Pole 66.5°N 23.5°S 66.5°S 90°S South Pole Arctic circle Tropic of Cancer Equator Tropic of Capricorn Different Latitudes

6 Rain and Wind

7 Rain Shadow Effect

8 What is the Greenhouse Effect?
Sunlight Some heat escapes into space Greenhouse gases trap some heat Atmosphere Earth’s surface What is the Greenhouse Effect?

9 II. The Greenhouse Effect
A. Temperatures on Earth remain for life because of the atmosphere. B. Gases Responsible for trapping heat energy: 1. Carbon dioxide – from burning of fossil fuels; rain forest deforestation and burning. Approx of the problem. 2. Methane – from livestock feedlots, swamps, and coal mines. Approx of the problem. 3. Water vapor suitable 50% 18%

10 4. CFC’s – formerly from spray cans, now from refrigeration; air conditioners. Approx of the problem. 5. Oxides of nitrogen – from power plants, industry (any heat producing process). Approx of the problem. 20% 10%

11 C. These gases function like the glass. windows of a greenhouse
C. These gases function like the glass windows of a greenhouse. These gases trap the inside Earth’s atmosphere. penetrates the gases of the atmosphere and strikes the Earth’s surface. Here it is transformed into heat or infrared energy (IR). Much of the IR escapes the atmosphere, while the remainder is absorbed and held in the atmosphere by heat energy of sunlight Ultraviolet light greenhouse gases.

12 Greenhouse Effect

13 2. With an increase of abnormally high. levels of carbon dioxide
2. With an increase of abnormally high levels of carbon dioxide and other greenhouse gases, more and more escaping IR is , thereby creating a pronounced global warming. human-created caught and held

14 Global Warming Global Warming

15 Global Warming Global Warming
Worldwide temperatures have climbed more than 1ºF over the past century.

16 D. The Probable Scenarios of Global Warming: 1. 2. Shift north of
3. An increase in 4. Sea level Droughts climatic zones destructive storm activity rise Check this out!

17 Quiz #1 What is weather? The day to day condition of Earth’s atmosphere at a particular time and place. What is climate? The average year after year conditions of temperature and precipitation in a particular region.

18 Quiz #1 cont. The greenhouse effect causes an increase in
Carbon dioxide Temperature Oxygen Water

19 Quiz #1 cont. Sunlight strikes the Earth’s surface most directly in what region? Polar zone Temperate zone Tropical zone

20 4-2 What Shapes an Ecosystem?
Objectives Identify interactions that occur within communities Describe how ecosystems recover from a disturbance

21 1. Competition Give me that nut! Between organisms of the same species

22 Between Organisms of different species

23 So what is this tree competing for?
Light Water Nutrients

24 I. Community Interactions
A. Community interactions, such as competition, predation, and various forms of symbiosis, can powerfully affect an ecosystem. 1. Competition: occurs when organisms of the same or different species attempt to use an ecological resource in the same place at the same time.

25 What are the possible outcomes of competition?
LOSE OR WIN Because The competitive exclusion principle states that no two species can occupy the same niche in the same habitat

26 Alternatives? vs. p. 92

27 Predation: one organism
on another organism captures and feeds


29 Predator or Prey? How can you tell?


31 B. Three Types of Symbiosis
1. Mutualism – both benefit EX: lichen (algae & fungus), clownfish and sea anemone P. 93


33 B. Symbiosis (cont.) 2. Commensalism – one benefits, other is neither helped or harmed. EX: hawks and cactus plants, epiphytes and trees, shrimp and sea anemones p. 93

34 B. Symbiosis (cont.) 3. Parasitism – one benefits, other not benefited. One lives in or on the body of another taking energy from the host. Host is not usually killed. Tapeworm

35 Tape worm: Can range from 1 m to 30 m in a Sperm Whale.
The head has a mouth with hooked appendages that allows it to hook to its host’s intestinal lining Right behind the head, the neck grows segments that make up the rest of the elongated worm The worm absorbs nutrients from its host May be picked up by swallowing a small amount of water from a lake or river. Also by eating undercooked meat. Head of a tapeworm

36 Oak Treehopper suck sugar rich juices from trees

37 Symbiotic Relationship
Draw this table on page 3 of your Lecture Notes Symbiotic Relationship Host Symbiont Commensalism Mutualism Parasitism + + + - +


39 Are Ecosystems & Communities always stable?
NO! Ecosystems and communities are ALWAYS CHANGING! Why? Natural processes/disturbances Human disturbances

40 II. Ecological Succession
A. Ecological succession = An ecological sequence of changes in the plants and animals making up a community in a given area. Succession is a gradual replacement of organisms in a given area over a period of time.

41 II. Ecological Succession
B. These changes are predictable and orderly and continue until a stable or Once reaching its biological destiny, C. Two general types: Primary & Secondary climax community is reached. a community retains the final complement of species which mature over time.

42 Primary Succession 1. Primary succession: a form of succession that begins with _ _. Assume no soil is present when this process begins. Examples: recently formed volcanic island or bare rock areas scoured by glacial action. bare rock

43 Primary Succession a. Pioneer species are the first to colonize the area. Example: b. As they grow, lichens produce carbonic acids which lichen (a combination of fungus and algae). slowly break down the parent rock to form a basic shallow pocket of soil.

44 Farmer slide

45 Examples of Primary Succession
Glacier Moss and Lichen

46 2. Secondary Succession This occurs in communities that were established and then disturbed in some manner. Example: burned over area of chaparral. The fire-ravaged area begins re-growth soon after the ashes cool down. This climax stage will generally be reached in years in most cases.


48 2. Secondary Succession (cont.)
The climax community will possess a high degree of stability Before: Forest Fire After: New Growth

49 Succession Video

50 Quiz #2 cont. A form of symbiosis in which both organisms benefit is called Mutualism Parasitism Commensalism Predation

51 Quiz #2 cont. Natural disturbances, such as fires or hurricanes, can result in Commensalism Competition Parasitism Succession

52 Quiz #2 cont. The first species to populate an area at the beginning of primary succession are called. . . Pioneer Species

53 4-3: Biomes Objective Identify the characteristics of major land biomes

54 4-3 Biomes I. BIOMES: are areas that are similar in climate and other physical factors. A. A biome is an environment that has a characteristic B. There are of biomes: 1. Land biomes 2. Aquatic biomes climax community 2 main types

55 Major Biomes

56 a. Tundra Precip: low Temp: summer mild, winter cold Soil: poor
Diversity: low Trees: absent Grasses: medium

57 Tundra Located in the far northern parts of North America, Europe, and Asia The tundra has permanently frozen subsoil called permafrost Insects, particularly flies, are abundant Vast numbers of birds nest in the tundra in the summer to eat the insects and migrate south in the winter. Principal mammals include reindeer, Artic wolves, Artic foxes, Arctic hares, lemmings, and polar bears Though the number of individual organisms in the tundra is high, the number of species is small

58 Permafrost

59 Tundra Plants Cool growing temperature Hair Small and low growing
Grow in clumps Dark in color

60 Tundra Animals Heat efficient body shapes Camouflage Specialized coats
Snow insulation Camouflage Hibernate or Migrate

61 b. Taiga/Conifer Forest
Precip: medium Temp: summer mild, winter cool Soil: poor, acidic Diversity: moderate Trees: dense Grasses: sparse

62 Taiga/Conifer Forest Found in the northern Canada and much of the world’s northern regions Dominated by conifer (evergreens) forests, like spruce and fir Landscape is dotted with lakes, ponds, and bogs Has very cold winters Is the largest terrestrial biome Characterized by heavy snowfall Principal large mammals include moose, black bear, lynx, elk, wolverines, and porcupines Flying insects and birds are prevalent in summer

63 Taiga Plants Needle like leaves help reduce water loss and aid in the shedding of snow The shape of many conifer trees helps shed heavy snow to save branches from breaking

64 Taiga Animals Hibernation Migration
Producing a thick layer of insulating feathers or fur

65 c. Temperate Deciduous Forest
Precip: variable Temp: mild Soil: rich Diversity: moderate Trees: medium Grasses: medium

66 Temperate Deciduous Forest/Boreal Forest
Found in the northeast of North America The leaves on some trees and plants change colors as the seasons change. Rich soil due to decomposition of leaf litter Principal mammals include: squirrels, deer, foxes, and bears that are dormant or hibernate through the cold winter

67 Temperate Deciduous Plants
Broad leaves can capture a lot of sunlight for a tree Thick bark protects against the cold winters In autumn, deciduous trees drop their leaves to minimize water loss

68 Temperate Deciduous Animals
Hibernation Migration Food storage (for the winter)

69 d. Grassland Precip: moderate Temp: summer hot Soil: rich
Diversity: moderate Trees: absent Grasses: dense

70 Grassland Characterized by low total annual rainfall or uneven seasonal occurrence of rainfall, making conditions inhospitable for forests Grass is the dominant plant life Serve as grazing areas for large numbers of animals or as farming grounds or plantations by humans Principal grazing mammals include bison and pronghorn antelope in the US, and wildebeest and gazelle in Africa Burrowing mammals, such as prairie dogs and other rodents, are common

71 Grassland Plants During a fire, while above-ground portions of grasses may perish, the root portions survive to sprout again Extensive root systems prevent grazing animals from pulling roots out of the ground Prairie grasses have narrow leaves which lose less water than broad leaves Many grasses take advantage of exposed, windy conditions and are wind pollinated Soft stems enable prairie grasses to bend in the wind

72 e. Tropical Rain Forest Precip: high Temp: hot Soil: poor
Diversity: high Trees: dense Grasses: sparse

73 Tropical Rain Forest Found near the equator with abundant rainfall, stable temperatures, and high humidity Has the greatest diversity of species of any biome Dominant trees are very tall with interlacing tops that form a dense canopy

74 Tropical Rainforest Plants
Some plants climb or grow on other plants to reach the sunlight Drip-tips on leaves help shed excess water Prop roots help support plants in the shallow soil Some plants collect rainwater into a central reservoir

75 Tropical Rainforest Animals
So many creatures living here, there is great competition for light, food, and space and as a result some animals have become specialized. This means that they adapted to eating a specific plant or animal that few others eat. Camouflage Poisonous animals use bright colors to warn predators

76 f. Desert Precip: low Temp: variable Soil: poor Diversity: moderate
Trees: sparse Grasses: sparse

77 Desert It receives less than 10in of rainfall per year; not even grasses can survive Experiences the most extreme temperature fluctuations of any biome. Characteristic plants are the drought-resistant cacti with shallow roots to capture as much rain as possible during hard and short rains.

78 Desert Plants The lack of leaves help reduce water loss. Leafless plants conduct photosynthesis in their green stems. Long root systems Spines discourage animals from eating plants for water. Flowers that open at night lure pollinators who are more likely to be active during the cooler night. Slower growing requires less energy Leaves with hair help shade the plant Waxy coating reduces water loss

79 Desert Animals Stay in the shade Burrow to escape the heat
Most animals are nocturnal (come out at night) Estivation—like hibernation, except these animals are not avoiding the cold, but the heat! Helps conserve moisture. Obtain water from diet

80 Quiz #3 Which biome has the lowest average temperatures? Highest?
Lowest Temp Tundra Highest Temp  Tropical dry forest Which biome has the lowest average precipitation? Highest? Lowest Precip  Desert & Tundra Highest Precip  Tropical rain forest

81 2. Aquatic biomes (cont.) a. Fresh water – streams, lakes, ponds, etc.

82 b. Salt water (marine): main photosynthesizers = phytoplankton

83 Estuary = most productive ecosystem on Earth

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