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Transcript of Chapter 1
1.1 = Biomes
1.2 = Ecosystems
2.1 Energy flow in ecosystems
2.2 Nutrient cycles in ecosystems
2.3 Effects of Bioaccumulation on ecosystems
biosphere= is the thin layer of air, land and water on or near the earths surface in which
all living things exist. It is divided into biomes and ecosystems
Biome= a region with similar biotic and abiotic components
Biotic= living Abiotic= non-living
Earth has 8 terrestrial biomes. Classified by water availability, temperature and interactions between biotic and abiotic.
- Boreal forest - Temperate
- Desert deciduous forest
- Grassland - Temperate rainforest
- Permanent ice - Tundra
Location- Upper northern hemisphere
Climate- precipitation 25 cm/summer temperature 3 to 12 degrees/winter temperature -20 to -30
Physical features- has a layer of permanent ice called permafrost. poor drainage because of flat terrain. topsoil thaws making pools and marshes( in summer) mostly cold and dark except in summer 24hr daylight.
Plant adaptations- no trees because of short growing seasons. ( roots can't penetrate permafrost ) To absorb warmth from the dark soil and avoid winds plants grow close to the ground. Flowering plants can survive because of fuzzy covering.
Animal adaptations- arctic foxes and hares have short legs and ears to reduce heat loss. animals slowly grow and reproduce less. birds migrate in this area because during summer bugs reproduce in great numbers.
Location- Northern hemisphere
Climate- precipitation 30 to 85 cm (mostly snow) below freezing half the year and drops to -40
Physical features- short summer growing season. Terrain is often rough and soil can be wet because of marshes, shallow lakes and wetlands.
Plant adaptations- trees mostly cone-bearing (black and white spruce) with waxy needles that allow snow to fall of and water resist. few understorey plants because little light reachs the forest floor.
Animal adaptation to retain their body heat.s- Seed eaters stay year-round. chipmunks and shrews burrow in winter to stay warm. Large bodies enable moose to retain body heat. To camouflage snowshoe hares change colors to hide from predators. Reptiles and amphibians are rare because they can't survive in low temperatures.
Temperate Deciduous Forest
Location- Eastern Canada, U.S.A, Asia, western Europe, Southern Australia and New Zealand.
Climate- rainfall 75-180 cm. Temperatures are -30 in winter and 30 in summer.
Physical features- season changes between summer and winter are big, also temperatures have the same affect. four distinct seasons and long warm growing season. soil is enriched by fallen leaves that provide nutrients.
Plant adaptations- plants grow in 4-5 layers. in the canopy is maple,oak and birch trees. second layer has shorter trees. Third layer has shrubs. fourth layer has ferns, herds and mosses on the forest floor. Trees shed large leaves in winter to prevent water loss and reduces breakage with heavy snow.
Animal adaptations- the many layers provide lots of habitat space for rabbits,deer,wolves,bears and amphibians.
Location- Coast of Chile in south America, northwest coast of north America, coastal British Columbia, New Zealand and southern Australia.
Climate- Rainfall over 200 cm a year. Temperature from 5-25 degrees. ( fog adds moisture )
Physical features- Occur in narrow strips by coastlines backed by mountains. the ocean drops moisture on the windward side of the mountains.
Plant adaptations- trees grow tall because of lots of rainfall. Mosses and lichens cling on trees to receive more light.
Animal adaptations- animals live on of near the forest floor to avoid wind and rain. Insects live in tree bark and decompose plant matter. These insects are eaten by birds with long beaks and amphibians with sticky tongues.
Location- Canada, North America, Russia, Equator in Africa, South America, and Northern Australia.
Climate- precipitation is 25-100 cm. Summers are 30 degrees and winters are -10. Tropical grasslands precipitation is 50-130 cm. Daily temperatures from 20-30 degrees.
Physical features- Both grasslands are mainly flat land. Temperate grassland has rich and fertile soil because of growth and decay of deep grass rocks. Tropical grasslands are less rich because heavy rain washed away nutrients. In both grasslands soil erosion occurs because of strong winds. Precipitation occurs in late spring or early summer, followed by a dry period. Grass fires can occur in both grasslands.
Plant adaptations- Both grassland trees are scarce because of limited rainfall. Fire and grazing animals kill seedlings. Temperate grasslands, grass such as blue grama and buffalo grass are adapted to drought because their roots are deep and form dense mats that collect water. Because of well-adapted root systems plants can regrow after fires. Wind cant break stalks because they are flexible. Wildflowers such as asters, goldenrod, and dover grow between grasses. Tropical grasslands, grasses also have deep roots and some grasses have sharp edges or are too bitter for grazing.
Animal adaptations- Large grazing mammals are present in large numbers because there is plentiful grass. Animals such as antelope are found in both biomes and have flat teeth that grind plant materials. tropical grasslands, herds of antelope, giraffes and zebras are found with predators such as lions, cheetahs and leopards. Temperate grasslands, large mammals include antelope, wild horses,kangaroos and predators such as wolves and coyotes. Mice, rabbits, gopher sand snakes are common to both grasslands. these animals burrow to fire, predators and extreme weather.
Location- 4800 km wide around the equator. Mostly between the tropic of cancer and the tropic of capricorn. Also much of northern/south america, central america/africa and south east asia.
Climate- rainfall is 250 cm per year. Temperature is 20-25 year-round.
Physical features- because nutrients are quickly recycled and not retained, (Also because heavy rain washes minerals away) soil is poor. The forest floor is dark which limits plant growth.
Plant adaptations- the largest number of different plant species.(grow in layers). Tall trees form dense canopy that absorbs most sunlight. Vines climb trees to get more sunlight. Orchids reach sunlight by growing on tall trees. Leaves have narrow tips so water falls quickly off to avoid breakage.
Animal adaptations- Great diversity of animals but few large mammals. Because of little vegetation on the forest floor animals adapt to live in trees. Some animals secrete poisons that protect them from predators.
Location- Hot deserts are found on every continent. Cold desert are found in North America, Argentina and Central Asia.
Climate- rainfall is lees than 25 cm. Hot days 38 degrees and cold night 7 degrees. summer days 21 to 26 degrees and winter days -2 to 4 degrees.
Physical features- (hot deserts)little or a lot of rain in short periods.Because minerals don't get washed away the soil is salty.(cold deserts) Precipitation is mostly snow but rain in spring. soils is saltly and little water erosion occurs.
Plant adaptations- Hot deserts have few plant species.( Spiny cacti that have thick, fleshy stems that conserve water are common, their roots extend meters away from the plant to absorb water. Other plants have thick, waxy leaves that also store water. ) many plants have spines or produce chemicals to protect themselves. In cold deserts few plant species and less than 1 m tall. Sagebrush, are deciduous and have spiny leaves. also their roots can extend 30 m and absorb water.
Animal adaptations- In hot deserts reptiles are common and have thick skin and scales that prevent water loss. Spadefoot toads and scorpions bury themselves in the ground and sleep during times of heat and drought. animals are active at night when its cold. In cold deserts, fan-throated lizards, small mammals, such as foxes burrow to escape the cold.
Location- Arctic, Greenland and the Antarctica.
Climate- Precipitation less than 50 cm and mostly snow. The Antarctica lowest temperature is -89 degrees. the Arctics average temperature is from 9 degrees on the coast and -30 inland. Arctic summer temperatures are from 3 - 14.
Physical features- Strong winds and little soil. Little fresh water is available because of freezing conditions
Plant adaptations- Lichens ( organisms that consist of fungi and algae ) can tolerate drought and cold and are dark-colored, thus absorbing more sunlight. Species of moss survive in the arctic, but few grew in Antarctica. Only two flowering plants in antarctica but more than 100 in Arctic, because of it's brief growing season.
Animal adaptations- The arctic has polar bears, walruses, seals, arctic foxes and insects. Antarctica has mostly penguins and marine mammals ( leopard seals ) penguins fat layers and packed feathers retain body heat. Walruses have no external ear, which reduces heat loss and they lie close in herds thus retaining heat.
Influences of Biomes
Temperature and Precipitation
Latitude ~ Above or below the equator
Temperature and Precipitation
Temperature/ precipitation include rain, snow, mist and fog
Are the most important abiotic factors that influence Biomes.
Is the Distance north and south of the equator. (Affects temperature/Precipitation)
Equator receives 12hrs of sunlight each day.
Tropical zone has warm temperatures and high precipitation.
Away from the equator the sun's rays are less intense causing low temperatures in the temperate zone.
Direct sunlight heats the air at the equator.(warm air holds more moisture than cold air)when warm air rises it cools and falls back as rain.
because of little mositure the temperate zone has low precipitation.
Is the height of a land-mass above sea level
high elevations have little air so less heat is retained.
Windward sides of mountains are wet because clouds filled with mositure rise and cool, then release rain or snow. Leeward sides are very dry warm air absorbs water, creating a dry land area.
Carry warmth and moisture to coastal ares
Temperate biomes are found where warm currents meet land.
Are two graphs together
Climate refers to the average pattern of weather conditions over a period of several years.
Shows the average temperature and precipitation for a location over a period of 30 years or more.
An adaptation is a characteristic that allows an organism to better survive and reproduce.
A physical feature that helps an organism survive
Ex. A wolf has large paws to help it run in snow
A physical or chemical event inside the body of an organism that allows it to survive
Ex. A wolf maintains a constant body temperature
A behavioral that helps an organism to survive
Ex. A wolf hunts in packs to capture large prey.
To better understand what may happen in the future, we study past and present ecosystems.
Many first nations sources provide detailed knowledge of pants, animals and natural occurrences of an area.
Historical ecology is the study of natural and written materials to better understand the ecology of a certain area
Parts of an Ecosystem
Abiotic factors include air, water, soil, nutrients and light.
Biotic factors include plants, animals and micro-organisms
Can take up hectares of land or can be small.
Abioic components are what allow biotic components to survive.
Nutrients enter the food chain through plants and important for growth.
light is need for photosynthesis
Soil is home for many plants and animals.
Community - All organisms that interact within
Species - Organisms within an ecosystem that
have the same structure and that can
reproduce with each other
Population - Members of a certain species within an
Are the interactions between members of two different species that live together in a close association.
Commensalism- One species benefits, other not affected
Ex. Barnacles on a whale
Mutualism- Both species benefits
Ex. Bee gathering nectar from a flower
Parasitism- One species benefits, other harmed
Ex. Hookworm living in dogs
Niche- Role an organism has within an ecosystem,
physically, chemically and biologically.
Competition- When a resource is needed by two or
Means resources are limited
Predation- Relationship between the predators and
Predators have adaptations to help them catch their prey.
Prey have adaptations to help avoid predators.
Examples of adaptations include spines and shells, camouflage and mimicry
The numbers of predators and prey influence each other.
By: Neetu Dha for Friza
Energy flow in ecosystems
Biomass is the total mass of all living things in a given area. Within an organism's niche, the organism interacts with the ecosystem by:
1) Obtaining energy from the ecosystem
2) Contributing energy to the ecosystem
plants are called "Producers" because they produce carbohydrates,water and sun's energy
"consumers" get their energy by feeding on producers or other consumers
Decomposition is the breaking down of wastes and dead organisms, by organisms called "decomposers" (detrivores) through the process of biodegradetion.
Energy flow and energy loss
Scientist use different methods to represent energy moving through ecosystems:
Food chains show the flow of energy in an ecosystem. Each step in a food chain is a trophic level.
1 trophic level - Producers
2 trophic level - Primary consumers
3 trophic level - Secondary consumers
4 trophic level - Tertiary consumers
Consumers in a food chain can be classified as:
1) Detrivores- consumers that obtain energy and nutrients from dead organisms and waste matter.
Includes small insects, earthworms, bacteria and fungi
Detrivores have their own, separate food chains and are very numerous
Detrivore feed at every trophic level
2) Herbivores- primary consumers
Herbivores eat plants (producers) only
3) Carnivores- secondary or tertiary consumers
Secondary consumers eat non-producers such as herbivores
Tertiary consumers eat secondary consumers
4) Omnivores- consumers that eat both plants and animals
Examples include humans and bears
Most organisms are part of many food chains
Food webs represent interconnected food chains
Food webs are models of the feeding relationship in an ecosystem
Arrows in a food web represents flow of energy and nutrients
following the arrows leads to the top carnivore.
Food Pyramids show the changes in available energy from one trophic level to another in a food chain.
Energy enters at the first trophic level, where there is a large amount of biomass and therefore much energy.
it takes large quantities of organisms in one trophic level to meet the energy needs of the next trophic level.
Each level loses large amounts of the energy it gathers through basic processes of living
80% - 90% of energy taken in by consumers is used in chemical reactions in the body and is lost as heat energy.
There is very little energy if left over for growth or increase in biomass.
Food pyramids may show biomass, population or energy numbers.
The amount of life an ecosystem can contain is based on the bottom level of the ecological pyramid, where producers capture energy from the sun.
Each level in the energy pyramid = a loss of 90% of total energy available
Tower trophic levels have much larger populations than upper levels.
This shows the importance of maintaining large, biodiverse populations at the lowest levels of the pyramid
Food pyramids are also known as ecological pyramids.
Nutrients cycles in
Nutrients cycles in Ecosystems
Nutrients are chemicals required for growth and other life processes.
Nutrients move through the biosphere in nutrient cycles or exchanges
Nutrients often accumulate in areas called stores
Without interference, generally the amount of nutrients flowing into a store equals the amount of nutrients flowing out.
Human activities can upset the natural balance of nutrient cycles.
Land clearing, agriculture, urban expansion, mining, industry and motorized transportation can all increase the levels of nutrients more quickly than the stores can absorb them.
Excess nutrients in the biosphere can have unexpected consequences.
There are five chemical elements required for life.
Carbon, hydrogen, oxygen and nitrogen cycle between living things and the atmosphere.
Phosphorous cycles in from sedimentary rock.
Carbon atoms are a fundamental unit in cells of all living things.
Carbon is also an essential part of chemical processes that sustain life.
Carbon can be stored in many different locations.
Short-term shortage is found in acquate and terrestrial organisms and in CO2 in the atomsphere and top layers of the ocean.
Longer-term shortage is found in middle and lower ocean layers as dissolved CO2 and in coal, oil and gas deposits in land and ocean sediments.
Sedimentation traps many long-term stores of carbon.
Layers of soil and decomposing organic matter become buried on land and under the oceans
Slowly, under great pressure over many years, coal, oil and gas form
Layers of shells also are deposited in sediments on the ocean floor, forming carbonate rocks like limestone over long periods of time.
Carbon stores are also known as carbon sinks.
Carbon is cycled through ecosystems in variety of ways.
* Photosynthesis: Energy from the sun allows CO2 and H2O to react.
Carbon in the atmosphere is transformed by plants into carbohydrates
Photosynthesis also occurs in cyonbacteria and algae in oceans.
* Cellular respiration: Carbohydrates release energy in consumers.
C6H12O6+O2-> CO2+H2O+ energy
The energy released is used for growth, repair and other life processes
* Decomposition: Decomposers break down large quantities of cellulose.
Celloulose is a carbohydrate most other organisms cannot break down.
* Ocean processes: CO2 dissolves in cold, northern waters and sinks.
Ocean currents flow to the tropics, the water rises and releases CO2
This process is called ocean mixing
* Eruption & Fires: Volcanic eruption can release CO2.
Forest fires release CO2
Many human activities can influence the carbon cycle.
- Since the start of the industrial revolution (160 years ago), CO2 levels have increased by 30% from the the increased burning of fossil fuels.
Carbon is being removed from long-term storage more quickly than it naturally would as we mine coal and drill for oil and gas.
CO2 is also a greenhouse, which traps heat in the atmosphere.
- Clearing land for agriculture and urban development reduces plants that can absorb and convert CO2.
farmed land does not remove as much CO2 as natural vegetation.
The Nitrogen Cycle
Nitrogen is very important in the structure of DNA and protein
In animals, proteins are vital for music function
In plants, nitrogen is important for growth
The largest store of nitrogen is in the atmosphere in the form N2 (gas)
Approximately 78% of the earth's atmosphere is N2 gas
Nitrogen is also stored in oceans and as organic matter in soil
Smaller nitrogen stores are found in terrestrial ecosystems and waterways.
Nitrogen is cycled through processes involving plants.
1) Nitrogen Fixation
Nitrogen fixation is the conversion of N2 gas into compounds containing nitrates (NO3-) and ammonium (NH4+)
Both nitrate and ammonium compounds are usable by plants
Nitrogen fixation occurs in one of three ways
1) In the atmosphere - lighting provides the energy for N2 gas to react with O2 gas to form nitrate and ammonium ions.
Compounds formed by these ions then enter the soil via precipitation
This only provides a small amount of nitrogen fixation
2) In the soil - nitrogen-fixing bacteria like Rhizobium in the soil convert N2 gas into ammonium ions
These bacteria grew on the root nodules of legumes like peas
The plants provide sugars, while bacteria provide nitrogen ions
3) In the water - some species of cyanbacteria also convert N2 into ammonium during the process of photosynthesis
Nitrification occurs when certain soil bacteria convert ammonium
Ammonium is converted into nitrite (NO3-) by nitrifying bacteria
Ammonium is converted to nitrite (NO2-), which is then converted to nitrate
Nitrates enter plant roots via uptake (absorbtion)
These nitrogen compounds compose plant proteins
Herbivores then eat plants and use nitrogen for DNA and protein synthesis
Nitrogen is returned to the atmosphere via denitrification
Nitrates are converted back to N2 by denitrifying bacteria
N2 is also returned to the atmosphere through volcanic eruptions
Excess nitrogen dissolves in water, enters the waterways and washes into lakes and occeans
The nitrogen compounds eventually become trapped in sedimentary rocks and will not be released again until the rocks weather.
Human activities can also affect the nitrogen cycle
Due to human activities, the amount of nitrogen in the ecosystems has doubled in the last 50 years
Burning fossil fuels and treating sewage releases nitrogen oxide (NO) and nitrogen dioxide (NO2)
- Burning also releases nitrogen compounds that increase acid rain precipitation in the form of nitric acid (HNO3)
Agriculture practices often use large amounts of nitrogen-containing fertilizers
Excess nitrogen is washed away or leaches into the waterways
This promotes huge growth in aquatic algae = eutrophication
These algal blooms are use up all Co2 and O2 and block sunlight, killing many aquatic organisms
The algal blooms can also produce eurotoxins that poison animals
The Phosphorous Cycle
Phosphorous is essential for life processes in plants and animals.
Phosphorous is a part of the molecule that carries energy in living cells
Phosphorous promotes root growth, stem strength and seed production
In animals, phosphorous and calcium are important for strong bones.
Phosphorous is not stored in the atmosphere
Instead, it is trapped in phosphates found in rocks and in sedimens on the ocean floor.
Weathering releases these phosphates from rocks
Chemical weathering, via acid precipitation or lichens, releases phosphates.
Physical weathering, where wind, water and freezing release the phosphates
Phosphates are then absorbed by plants, which are then eaten by animals
Weathering doesn't occur until there is geologic uplift exposing the rock to chemical and physical weathering
Humans add excess phosphorous to the environment through mining for fertilizer components.
Extra phosphorous, often long with potassium, then enters the ecosystems faster than methods can replenish the natural stores
Humans can also reduce phosphorous supplies
Slash and burning of forests removes phosphorous from trees and it then is deposited as ash in waterways.
How changes in Nutrients Cycles affect Biodiversity
Any significant changes to any of these nutients (C, H, O, N or P) can greatly impact biodiversity (more organisms stronger the ecosystem)
Carbon cycle changes are add to climate change and gobal warming
- Slight temperature fluctuations and changes in water levels can drastically change ecosystems.
- Changes influence every other organism in these food webs (interconnected)
Increased levels of nitrogen can allow certain plant species to out compete other species, decreasing resources for every species in these food webs.
Decreased levels of phosphorous can inhibit the growth of algal species which are very important producers in many food chains.
Effect of Bioaccumulation on Ecosystems
Amphibians live on both land and in the water
amphibians are sensitive to chemical changes in the environment
They are therefore valuable indicators of environment health
Since the 1980's, many of the world's amphibian species have suffered declines in population
There also have been alarming increases in amphibian birth deformities
Many theories attempt to explain these changes, including drought, increased UV rays, (depletion of ozone layer) pollution, habitat, parasites and disease.
Bioaccumulation refers to the gradual build up of chemicals in living organisms
Many harmful chemicals cannot be decomposed naturally
These chemicals can be eaten or absorbed and sometimes cannot be removed from the body of the organism effectively
If a keystone species suffers a chemical bioaccumulation it can affect every other organism in its far-reaching niches.
- A keystone species is a vita part of an ecosystem
Biomagnification is the process by which chemicals become more concentrated at each trophic level
At each level of the food pyramid, chemicals that do not get broken down build up in organisms
When a consumer in the next trophic level eats organisms with a chemical accumulation, it recovers a huge dose of the chemicals.
An example of bioaccumulation in British Columbia is the affect of PCB's on the area
PCB's are chemicals that were used for many industrial and electrical applications in the mid-20 century
PCB's were banned in 1977 because of their environment impact
- PCB's bioaccumulate and have a long half- life (they break down very slowly)
- PCB's will affect the reproductive cycles of areas until at least 2030
Chemicals like PCB's and DDT are called persistant organic pollutants (POPs)
POPs contain carbon, like all organic compounds and remain in water and soil for many years
Many POPs are insects, used to control pest populations.
- DDT was introduced in 1941 to control mosquito populations and is still used in some places in the world
-Like PCBs, DDT also bioaccumulates and has a long half-life
- Even at low levels (5 ppm), DDT in animals can cause nervous, immune, and reproductive system disorders
ppm = parts per million (The lower the ppm number, the more dangerous a substance)
Heavy are metallic elements that are toxic to organisms.
Levels of lead in the soil have increased due to human activities
Lead is not considered safe at any level
Many electronics contain lead and must be recycled carefully
Lead can cause anemia and nervous and reproductive system damage
Cadmium is also found in low levels naturally
Cadmium is used in the manufacture of plastics and nickel - cadmium batteries
It is toxic to earthworms and causes many health problems in fish
In humans, the main source of cadmium is exposure to cigarette smoke
Cadmium causes lung diseases, cancer and nervous/immune system damage.
Mercury also is found naturally
Mercury has entered ecosystems through the burning of fossil fuels, waste incineration, mining and the manufacture of items like batteries
Coal burning accounts for 40% of the mercury released into the atmosphere
Mercury bioaccumulate in the brain, heart and kidneys of many animals
Mercury compounds bioaccumulate in fish, adding risk for any organisms eating fish
Reducing the effects of chemical pollution
Bioremediation is the use of micro-organisms or plants to help clean up toxic chemicals
- Ex. Oil industry uses bacteria to "eat" oil spills by trapping chemicals in the soil, they cannot enter the food chains as easily.