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ลำดับตอนที่ #3 : [[R.S.]]Biology Test::Chapter 3-4.1+4.2::3.10.08
The Summary of Biology for
Chapter 3 :: The Biosphere &
Chapter 4 :: Ecosystems and Communities
Chapter.3 :: The Biosphere [[Page.62]]
3-1 What Is Ecology? [[Page.63]]
- Ecology is the scientific study of interactions among organisms and between organisms and their environment, or surroundings.
- The largest house for living things are called biosphere.
· The biosphere contains the combined portions of the planet in which all of life exists, including land, water, and air, or atmosphere.
- To understand relationship within the biosphere, ecologists ask questions about events and organisms that range in complexity from a single individual to the entire biosphere.
1. Species = a group of organisms so similar to one another that they can breed and produce fertile offspring.
2. Populations = a groups of individuals that belong to the same species and live in the same area.
3. Communities = assemblages of different populations that live together in a defined area.
4. Ecosystem = a collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment.
5. Biome = a group of ecosystems that have the same climate and similar dominant communities.
- Regardless of the tools scientists use, they conduct modern ecological research using three basic approaches :: observing, experimenting, and modeling. All of these approaches rely on the application of scientific methods to guide ecological inquiry.
· Observing = first step in asking ecological questions.
· Experimenting = used to test hypotheses. They may be set up in laboratory or within natural ecosystem.
· Modeling = ecologists make models to gain insight into complex phenomena; the predictions made by ecological models are often tested by further observations and experiment.
3-2 Energy Flow [[Page.67]]
- Sunlight is the main energy source for life on Earth.
- Some types of organisms rely on the energy stored in inorganic chemical compounds.
- Organisms like plants, some algae, and certain bacteria that can capture energy from sunlight or chemicals and use that energy to produce food are called autotrophs.
· They use energy from environment to fuel the assembly of simple inorganic compounds into complex organic molecules.
· They can make their own food, so they’re also called producers.
- The best-known autotrophs are those that harness solar energy through a process known as photosynthesis.
· During photosynthesis, these autotrophs use light energy to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates [[such as sugar/starches]]
· It adds oxygen to – and removing carbon dioxide from – Earth’s atmosphere.
· The most common photosynthetic bacteria are the cyanobacteria.
- Some autotrophs can produce food in the absence of light.
· They rely on energy within the chemical bonds of inorganic molecules [[or what we call chemical energy]] to produce carbohydrates in the process known as chemosynthesis.
- Many organisms can’t harness energy directly, so the only way they can acquire energy is from other organisms.
- Organisms that rely on other organisms for their energy and food supply are called heterotrophs or consumers.
And there’re many different types of heterotrophs….
· Herbivores = obtain energy by eating only plants [[ex. cows, deer]]
· Carnivores = eat only animals [[ex. snakes, dogs]]
· Omnivores = eat both plants and animals [[ex. human, bears]]
· Detritivores = feed on plant and animals remains and other dead matter
[[ex. earthworm > <, snails]]
· Decomposers = breaks down organic matter [[ex. bacteria, fungi]]
- Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs [[producers]] and then to various heterotrophs [[consumers]].
- The energy stored by producers can be passed through an ecosystem along a food chain, a series of steps in which organisms transfer energy by eating and being eaten.
- When the feeding relationships among the various organisms in an ecosystem form a network of complex interaction, ecologists describe these relationships as a food web.
· A food web links all the food chains in an ecosystem together.
- Each step in a food chain or food web is called a trophic level.
- Each consumer depends on the trophic level below it for energy.
- An ecological pyramid is a diagram shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web.
- There are three different types of ecological pyramids ::
1. Energy Pyramid
= shows the relative amount of energy available at each trophic level.
= only about 10 percent of the energy available within one trophic level is transferred to organisms at the next trophic level [[becuz organism use much of the energy that they consume for life processes such as respiration, movement, and reproduction. Some of the remaining energy is released into the environment as heat.
2. Biomass Pyramid
= the total amount of living tissue within a given trophic level is called biomass
= represents the amount of living organic matter at each trophic level. Typically, the greatest biomass is at the base of the pyramid.
= expressed in terms of grams of organic matter per unit area.
3. Pyramid of Numbers
= shows the relative number of individual organisms at each trophic level.
3-3 Cycles of Matter [[Page.74]]
- Unlike the one-way flow of energy, matter is recycled within and between ecosystems,
- Elements, chemical compounds, and other forms of matter are passed from one organism to another & form one part of the biosphere to another through biogeochemical cycles.
- Biological cycles don’t use up matter, they transform it by pass the same molecules around again and again within the biosphere.
The Water Cycle
- Water moves between the ocean, atmosphere & land through the water cycles.
- Water molecules[liquid] enter atmosphere as water vapor[gas], they evaporate from the ocean or other bodies of water in the process of evaporation.
- Water can also enter the atmosphere by evaporating from the leaves of plants in the process of transpiration.
- During the day, the sun heats the atmosphere making the warm moist air to rise & cool. The water vapor then condenses into tiny droplets that form clouds.
- When the droplets become large enough, they returns to Earth in form of precipitation.
- Much of precipitation enters a river or stream that carries the runoff back to an ocean or lake. Some of them seeps into the soil deeply enough to become ground water.
- Water in the soil enters plants thorough the roots & the water cycle beings anew
Nutrient Cycles
- All the chemical substances that an organism needs to sustain life are its nutrients.
- Every living organism needs nutrients to build tissues and carry out essential life functions. Like water, nutrients are passed between organisms and the environment through biogeochemical cycles.
The Carbon Cycle
- Carbon is a key ingredient of living tissue in many forms such as calcium carbonate, carbon dioxide, or dissolved carbon dioxide.
- Four main types of processes move carbon thorough its cycle ::
1. Biological processes
ð Ex. photosynthesis, respiration, decomposition [[take up & release carbon + oxygen]]
2. Geochemical processes
ð Ex. erosion & volcanic activity [[release carbon dioxide to atmosphere+ocean]]
3. Mixed biochemical processes
ð Ex. burial & decomposition of dead organisms [[store carbon underground]]
4. Human activities
ð Ex. mining, cutting/burning forests or fossil fuels [[release carbon dioxide into atmosphere]]
The Nitrogen Cycle
- All organisms require nitrogen to make amino acids which are used to build proteins.
- Many different forms of nitrogen occur naturally in the biosphere, they also exist in several forms in the ocean & other large water bodies.
- Human activity adds nitrogen to the biosphere in the form of nitrate – a major component of plant fertilizers.
- Only certain types of bacteria can use nitrogen directly, such bacteria are called legumes. They convert nitrogen gas into ammonia in a process known as nitrogen fixation.
- Other soil bacteria convert nitrates into nitrogen gas in a process called denitrification. It releases nitrogen into the atmosphere once again.
The Phosphorus Cycle
- Phosphorus is essential to living organisms because it forms part of important life-sustaining molecules such as DNA and RNA.
- It remains mostly on land in rock and soil materials, and in ocean sediments and exists in the form of inorganic phosphate.
- As the rocks and sediments wear down, phosphate is released.
- On land, some of the phosphate eventually makes its way to the oceans, where it’s used by marine organisms.
- Ecologists are often interested in the primary productivity of an ecosystem, which is the rate at which organic matter is created by producers.
- It is affected by the amount of available nutrients.
- When an ecosystem is limited by a single nutrient that is scare or cycles very slowly, this substance is called a limiting nutrient.
- Because of that limiting nutrient, farmers apply fertilizers [[which contain nitrogen, phosphorus, potassium]] to their crops to boost their productivity.
- When an aquatic ecosystem receives a large input of a limiting nutrient, the result is often an increase in the number of algae/producers known as an algal bloom.
Chapter.4 :: Ecosystems and Communities [[Page.86]]
4-1 The Role of Climate [[Page.87]]
- Weather is the day-to-day condition of Earth’s atmosphere at a particular time and place.
- Climate refers to the average, year-after-year conditions of temperature and precipitation in a particular region.
- Climate is caused by the trapping of heat by the atmosphere, latitude, the transport of heat by winds & ocean currents, and amount of precipitation results.
- The shape and elevation of landmasses also contribute to global climate patterns
- The energy of incoming sunlight drives Earth’s weather and helps determine climate.
- Carbon dioxide, methane, water vapor, and a few other atmospheric gases trap heat energy and maintain Earth’s temperature range.
· Theses gases function like the glass windows of greenhouse, which trap the heat energy of sunlight inside Earth’s atmosphere.
· This situation is called the greenhouse effect.
- The difference in heat distribution which latitude has important effects on Earth’s climate zones.
- As a result of differences in latitude and thus the angle of heating, Earth has three main climate zones :: polar, temperate, and tropical.
1. The polar zones
= cold areas where the sun’s rays strike Earth at a very low angle
= located around the North and South poles
2. The temperate zones
= between the polar zones and the tropics
= are more affected by the changing angle of the sun over the course of a year, so the climate ranges from hot to cold, depending on the season.
3. The tropical zones [[tropics]]
= near the equator
= receive direct or nearly direct sunlight year-round making the climate almost always warm.
- The unequal heating of Earth’s surface drives wind and ocean currents, which transport heat throughout the biosphere.
- The upward movement of warm air and the downward movement of cool air create air currents, or winds, that move heat throughout the atmosphere, from regions of sinking air to regions of rising air.
- Cold water near the poles sinks and then flows parallel to the ocean bottom, eventually rising again in warmer region through a process called upwelling.
- The water flow creates ocean currents which transport heat energy within the biosphere.
- Earth’s winds and ocean currents interact to help produce Earth’s climates.
4-2 What Shapes an Ecosystem? [[Page.90]]
- Ecosystems are influenced by a combination of biological and physical factors.
· The biological influences on organisms within an ecosystem are called biotic factors. [[Ex. birds, trees, dogs, bacteria, etc.]]
· Physical, or nonliving, factors that shape ecosystems are called abiotic factors. [[Ex. temperature, precipitation, humidity, wind, etc.]]
- Together, biotic and abiotic factors determine the survival and growth of an organism and the productivity of the ecosystem in which the organism lives.
- The area where an organism lives is called its habitat.
- A niche is the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those condition.
- The combination of biotic & abiotic factors in an ecosystem often determines the number of different niches in that ecosystem.
- A niche includes the type of food the organism eats, how it obtains this food, and which other species use the organism as food.
- No two species can share the same niche in the same habitat.
- Community interactions, such as competition, predation, and various forms of symbiosis, can powerfully affect an ecosystem.
1. Competition
= when organisms of the same/different species attempt to use an ecological resource in the same place at the same time.
[[resources refer to any necessity of life, such as water, food, light, space]]
= a fundamental rule in ecology, the competitive exclusion principle, states that no two species can occupy the same niche in the same habitat at the same time.
2. Predation [[or Predator-Prey relationship]]
= one organism captures and feeds on another organism
= the organism that does the killing and eating is called predator, and the food organism is the prey.
3. Symbiosis
= any relationship in which two species live closely together
3.1 Mutualism
= both species benefit from the relationship.
3.2 Commensalism
= one member of the association benefits and the other is neither helped nor harmed.
3.3 Parasitism
= one organism lives on or inside another organisms and harms it.
- Ecosystems are constantly changing in response to natural and human disturbances. As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community.
· This series of predictable changes that occurs in a community over time is called ecological succession.
ð It’s caused by slow changes in physical environment, human activities, such as clearing a forest, or a sudden natural disturbance.
1. On land, succession that occurs on surface where no soil exists is called primary succession.
= Ex. occurs on the surfaces formed as volcanic eruptions build new islands or cover the land with lava rock or volcanic ash.
= The first species to populate the area [[in primary succession]] are called pioneer species.
2. When the disturbance [[from natural or human]] is over, community interactions tend to restore the ecosystem to its original condition through secondary succession.
3. Succession in a marine ecosystem
= occur in the permanently dark, deep ocean.
= Ex. whale-fall community
It begins when the whale dies. It attracts host of scavengers and decomposers feast on its decaying meat.
When several time passes, whale’s tissue have been eaten; it supports only a much smaller number of marine animals. Its decomposition enriches the surrounding sediments with nutrients and form oasis of sediment dwellers.
As only whale’s skeleton remains, heterotrophic bacteria decompose oils inside whale bones & they release chemical compounds for bacteria that are chemosynthetic autotrophs.
Ps. Rao mai dai read anything lei .. especially da last part
Rao mai dai proofread also .. la kor sry tee mai dai put pix of the cycles thingy hai
Rao reeeebbb makk jing jing !!
Download linkk*
http://upload.one2car.com/download.aspx?pku=4E6BF9B0CE3FNLR[SFZ2BQANSF3VV
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