CHAPTER 4:Ecosystems & Communities 4-1 The Role of Climate 4-2 What Shapes an Ecosystem 4-3 & 4-4 Biomes
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.
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.
4-1 The Role of Climate day-to-day condition 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 year-after-year conditions Latitude winds and ocean currents landmasses
Different Latitudes 90°N North Pole Sunlight 66.5°N Arctic circle Sunlight Tropic of Cancer Equator Most direct sunlight Tropic of Capricorn 23.5°S Sunlight Arctic circle 66.5°S Sunlight 90°S South Pole Unequal Heating of the Earth
What is the Greenhouse Effect? Sunlight Some heat escapes into space Greenhouse gases trap some heat Atmosphere Earth’s surface
suitable 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 50% 18%
20% 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. 10%
heat energy of sunlight C. These gases function like the glass windows of a greenhouse. These gases trap the inside Earth’s atmosphere. 1. 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 Ultraviolet light greenhouse gases.
Greenhouse Effect http://earthguide.ucsd.edu/earthguide/diagrams/greenhouse/
human-created caught and held 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.
Global Warming Global Warming
Global Warming Global Warming Worldwide temperatures have climbed more than 1ºF over the past century.
Droughts D. The Probable Scenarios of Global Warming: 1. 2. Shift north of 3. An increase in 4. Sea level climatic zones destructive storm activity rise Check this out! http://www.effectofglobalwarming.com/global-warming-pictures.html
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.
Quiz #1 cont. The greenhouse effect causes an increase in • Carbon dioxide • Temperature • Oxygen • Water
Quiz #1 cont. Sunlight strikes the Earth’s surface most directly in what region? • Polar zone • Temperate zone • Tropical zone
4-2 What Shapes an Ecosystem? Objectives • Identify interactions that occur within communities • Describe how ecosystems recover from a disturbance
Give me that nut! 1. Competition Between organisms of the same species
So what is this tree competing for? • Light • Water • Nutrients
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.
What are the possible outcomes of competition? WIN LOSE OR Because . . . . The competitive exclusion principle states that no two species can occupy the same niche in the same habitat
Alternatives? vs. p. 92
captures and feeds • Predation: one organism on another organism
B. Three Types of Symbiosis 1. Mutualism – both benefit EX: lichen (algae & fungus), clownfish and sea anemone P. 93
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
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
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
Are Ecosystems & Communities always stable? • NO! • Ecosystems and communities are ALWAYS CHANGING! • Why? • Natural processes/disturbances • Human disturbances
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.
II. Ecological Succession climax community is reached. B. These changes are predictable and orderly and continue until a stable or Once reaching its biological destiny, C. Two general types: Primary & Secondary a community retains the final complement of species which mature over time.
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. Primary Succession bare rock
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.
Examples of Primary Succession Moss and Lichen Glacier
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 12-15 years in most cases.
The climax community will possess a high degree of stability 2. Secondary Succession (cont.) Before: Forest Fire After: New Growth
Quiz #2 cont. A form of symbiosis in which both organisms benefit is called • Mutualism • Parasitism • Commensalism • Predation