notes on ecology. eco - household ology – study of ecology – study of the interactions between...
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Notes on Ecology
eco - household
ology – study of
Ecology – study of the interactions between organisms and the living (biotic) and nonliving (abiotic) components of their environment
Biosphere
Ecosystem
Community
Population
Organism
Levels of Organization in Ecology
Levels of Organization in Ecology
1. Biosphere
• refers to the thin volume of Earth and its atmosphere that supports life and abiotic factors
2. Ecosystem
• all the living and nonliving things in a particular place
Ex. pond, lake, forest
3. Community
• all the interacting organisms living in an area
Ex. all the plants, fish, bacteria, algae living in a pond
4. Population
• all the members of a species in one place at one time
Ex. All of the deer that live in the Chickamauga Battlefield now are a population
5. Organism
• simplest level of organization
• refers to individuals of a particular species
Biomes
Biome - A group of plants and animals in the same region and climate
Seven Terrestrial Biomes of the Earth
Tundra
Abiotic factors: strong winds, low precipitation; short, soggy summers; long, cold dark winters; poorly developed soils; permafrost
Dominant producers: mosses, lichens, sedges, short grasses
Dominant consumers: caribou, musk ox, arctic fox, lemming
N. Canada, N. Alaska
Latitudes:60-70º North
Taiga
Abiotic factors: long, cold winters; short, mild summers; moderate precipitation; high humidity; poor soils
Dominant producers: spruce, fir, small berry-bearing shrubs, some broadleaf deciduous trees
Dominant consumers: lynx, timber wolf, weasels, moose, grizzly bear
S. Canada, S. Alaska
Latitudes:50-60º North
Temperate Grasslands
Abiotic factors: warm to hot summers; cold winters; moderate seasonal precipitation; fertile soil; occasional wildfires
Dominant producers: lush grasses and herbs, most resistant to drought
Dominant consumers: bison, coyotes, badgers, wolves, prong-horned antelope, prairie dogs
Mid-Western U.S.
Latitudes:24-60º North or South
Temperate Deciduous Forest
Abiotic factors: cold to moderate winters; warm summers; year-round precipitation; fertile soils
Dominant producers: broadleaf deciduous trees, flowering shrubs, herbs, mosses, ferns
Dominant consumers: deer, black bears, bobcat, squirrels, raccoons, skunks, turkeys
Eastern U.S.;
Europe, NEAsia;
AustraliaLatitudes:
Mid-latitudes, north/south of
tropics
Desert
Abiotic factors: low precipitation; variable temperatures; soils rich in minerals but not in organic matter
Dominant producers: cactus, creosote bush, plants with short growth cycles
Dominant consumers: kangaroo rat, bats, roadrunners, rattlesnakes, lizards
Western U. S.;
Sahara Desert
Latitudes:18-28º N & S
Tropical Rainforest
Abiotic factors: hot and wet year-round; thin nutrient poor soils
Dominant producers: broadleaved evergreen trees, ferns, large woody vines and climbing plants, orchids, bromeliads
Dominant consumers: sloths, jaguars, anteaters, toucans, parrots, piranhas, caimans, boa constrictors, anaconda
Central America, Caribbean, & Southern tip of Florida;
Brazil, sub-Saharan Africa
Latitudes:23ºN to 23ºS
Savanna
Abiotic factors: warm temperatures; seasonal rainfall; compact soil; frequent fires set by lightning
Dominant producers: tall perennial grasses, some drought-tolerant and fire-retardant trees or shrubs
Dominant consumers: lions, leopards, cheetahs, hyenas, giraffes, elephants, wildebeest, zebras, baboons, termites
South America, Africa, India and Australia
Marine Biomes
Open Ocean:
Description: The type of organisms present depends on temperature, the amount of sunlight and nutrients available.
The ocean covers nearly ¾ of earth’s surface but most of ocean life is concentrated in shallow water around the edges of continents
Dominant producers: phytoplankton
Dominant consumers: zooplankton, jellyfish, seals, whales, sharks, dolphins
Coral Reefs:
Abiotic factors: warm, shallow enough for photosynthesis
Dominant producers: seaweed, tiny floating plants, phytoplankton
Dominant consumers: tropical fish, snails, clams, sponges, moray eels, anemones
Energy Flow through an ecosystem
A. Producers
• autotrophs that can make their own food from sunlight or chemicals
• change carbon dioxide and water into oxygen and sugars and starches
• photosynthesis:
• chemosynthesis: bacteria use chemical energy to make carbohydrates
6CO2 + 6H2O C6H12O6 + 6O2
B. Consumers
• Heterotrophs that rely on other organisms for food and energy
Herbivores – eat plants
Carnivores – eat meat
Omnivores – eat plants and meat
Detritivores – eat plant / animal remains
Decomposers – breakdown organic matter (bacteria, fungi)
C. Feeding Relationships
Sun
Autotroph
Heterotroph
Decomposer
Food Chains – step by step eating relationship
• ex: Zebra eats grass
Lion eats zebra
Food Webs – link of all the food chains
Trophic Levels – each step in a food chain or a food web
1st level – primary producers (autotrophs)
2nd level – primary consumers (herbivores)
3rd level – secondary consumers (carnivores that eat herbivores)
4th level – tertiary consumers (top carnivores)
The transfer of energy through an ecosystem can be represented by an energy pyramid
• only 10% of energy is available for the next trophic level
Biomass – the amount of organic matter in an ecosystem
• as the trophic level goes up, the percentage of biomass goes down
Lowest % of biomass
Highest % of biomass
Matter recycles through the biosphere through Biogeochemical Cycles
1. Water Cycle
2. Carbon Cycle
3. Nitrogen Cycle
4. Phosphorous Cycle
The Water Cycle
condensation
evaporation transpiration
runoff
precipitation
seepage
uptake
Carbon Cycle
Burning
Cellular Respiration
Photosynthesis
The Nitrogen Cycle
Atmospheric fixation
Bacterial
in Atmosphere
Soil
Ammonia
(NH3)
N2
N2
NitratesN2 fixation
Phosphorus Cycle
Phosphate rocks
Animal waste and decomposition
Notes on Communities
Communities – groups of interacting populations within an ecosystem
Species Interactions within the communities
1. Mimicry
• harmless species resembles a poisonous or distasteful species
• often mistaken to be dangerous
Ex. king snake looks like the poisonous coral snake, bees, wasps
2. Plant-Herbivore Interaction
• physical defenses such as thorns, spines, tough leaves
• chemical defenses such as poisonous, irritating, or bad-tasting compounds
Ex. Strychnine (found in the leaves of plants in the genus Strychnos), nicotine (found in the leaves of tobacco plants are poisonous to insects), poison ivy
3. Symbiosis – living together in close association
a. Parasitism
• one individual is harmed, while the other is benefited
• parasite – feeds on another individual (benefited)
• host – individual being fed on (harmed)
• does not lead to immediate death
2 Types of Parasites
• ectoparasites – external parasites such as fleas and ticks
• endoparasites – internal parasites such as tapeworms and bacteria
b. Mutualism
• cooperative relationship in which both species benefit
Ex. lichens, flowers, and insects
c. Commensalism
• a cooperative relationship in which one species benefits and the other is not affected
Ex. shark and remora
4. Predation – the way in which food is primarily obtained by the killing and consuming of animals
• predator’s survival depends on the ability to capture food
• prey’s survival depends on the ability to avoid being captured
Succession – gradual, sequential regrowth of a species in an area
1. Primary succession – growth on surfaces where no soil exists
Ex. bare rock, volcanic eruption
• pioneer species is the first species to grow
Ex. lichen
2. Secondary Succession – soil is left intact
• usually takes about 100 years to return to previous state
• typically begins with annual grasses, mustards, and dandelions
3. Climax Community – a stable end point to succession
• very rare, usually most are disturbed
Notes on Population
• number of species at a particular place at a particular time
• dynamic (changing)
1. Population Size
• number of individuals it contains
• usually estimated
2. Population Density
• number of individuals per unit area or volume
• in the US, there is on average 30 people/km2
Country Population Density (individuals/km2)
Japan 330
United Kingdom 240
Kenya 50
Mexico 50
United States 30
Russia 10
Population Distribution Patterns
Distribution – pattern of where an organism lives
• random distribution – no set pattern of individuals in the ecosystem
• clumped distribution – individuals are found in close knit groups usually near a resource
• even distribution – individuals are evenly spaced in the ecosystem
Factors of Changing Population
• Populations are constantly changing due to the immigration (moving in) and emigration (moving out) of individuals
1. birth rate – number of births per unit time
2. death rate (mortality) – number of deaths per unit time
3. life expectancy – the average life span of a person
• in US in 2006, the average life expectancy of a man was 76 and for a woman it was 81
4. Competition – organisms competing for resources
5. Natural disasters – limits organism growth and resource availability
Growth rate – the amount by which a population’s size changes in a given amount of time
1. Immigration – the movement of individuals into a population (Adding individuals)
Ex. Birth
2. Emigration – the movement of individuals out of a population (Removing individuals)
Ex. Death
Checking Population GrowthConcepts in Nature 4:46 – 10:51
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The Exponential Model
• population increases rapidly
• the larger, the faster it grows
• occurs naturally for short periods of time due to “Boom and Bust”
• the limiting factor will restrict exponential growth in real situations
• limiting factors include food, disease, growth, and reproduction
Ex. Bacteria in labs can grow exponentially as long as waste is removed and food is provided in abundance
• also called the J-curve
Carrying capacity
Time
The Logistic Model
• population growth includes limiting factors
• includes the carrying capacity (K) – the number of individuals the environment can support over a long period of time
Ex. Stable Growth Pattern
• the population can level off and fluctuate slightly above and below the carrying capacity
Carrying Capacity
Carrying CapacityConcepts in Nature 3:17 – 4:45
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Survivorship Curves
Survivorship Curves – a generalized diagram showing the number of surviving members over time from a measured set of births
Three types of curves
Type I
Type II
Type III
Type I
• common among large mammals, including humans
• shows low level of infant mortality and a population that generally will survive until old age
number
age
Type II
• organisms such as birds, small mammals, and some reptiles
• shows a survival rate that is roughly equal at all age levels of an organism’s life
• at all times, the species have equal chances of living and dying
number
age
Type III
• organisms include invertebrates, fish, amphibians, and plants
• have a very high birth rate and also a very high infant mortality rate
• many offspring die from predation, but inevitability a few will survive to adulthood and be able to pass their genes on to the next generation
number
age
Organisms and their Environment
Habitat – where an organism lives
Biotic Factors – living components of the environment
Abiotic Factors – physical and chemical aspects of the environment
• climate, temperature, precipitation, humidity, wind, nutrient availability, soil type, sunlight
Niche – the role of a species in its environment; especially feeding habit
Generalists
• species that have broad niches
Ex. cockroaches, humans
Specialists
• species that have narrow niches
Ex. Panda bear (only eats bamboo)
Koala (only eats eucalyptus)
Biodiversity – number of different species in the biosphere
• 1.5 million species now
Human Influences Threatening Biodiversity
• altering habitats – developing land splits ecosystems into pieces – habitat fragmentation
• species more vulnerable to disturbance
• hunting to extinction – occurs when a species disappears from a range
• international list that bans trade – CITES = Convention on International Trade in Endangered Species
• toxic compounds into food webs – biological magnification
Ex. DDT
Bioaccumulation & BiomagnificationDDT and Bald Eagles 3 min
Bioaccumulation & BiomagnificationMercury 3 min
• foreign species to new environment – no natural predators or parasites; no population control – invasive (exotic) species
Ex. Kudzu, zebra mussel
Acid Rain
• Acid in rain from the burning of fossil fuels (sulfur deposits)
Greenhouse Effect
• sometimes called global warming
The more CO2 the hotter the earth will be
• CO2 acts like a blanket on earth
• CO2 is release when fossil fuels (coal, oil, natural gas) are burned
• January 1940 the average temperature was 35.4° F
Global Warming in Ringgold?
• January 2011 the average high temperature was 50.0° F
Most scientists now call this phenomenon “global climate change” –the sum of human impact on our weather patterns.
Climate change indicates the shift toward extreme weather patterns across the globe (not just an increase in temp). The year 2011 is a prime example of extreme weather.
Click on this link for more info: http://www.noaa.gov/extreme2011/index.html
• January 1940 the average high temperature was 35.4° F
Global Warming in Ringgold
• January 2011 the average high temperature was 50.0° F
Ozone Depletion
• O3 is found in the upper atmosphere where it is used to screen harmful UV rays
• chlorofluorocarbons (CFC’s) destroy O3 molecules
UV rays cause cancer and cataracts
CFC’s found in aerosol cans-stopped producing in 1995
• O3 in polar regions have been destroyed the most
1980 2005
Water Pollution
Many types:
• fertilizer – wash off from plowed fields
• biological pollution (bacteria, viruses)
• radioactive substances
• petroleum (oil)
Waste • Solid, liquid and gas wastes
• Some waste is hazardousFlammable, Unstable (explosive), corrosive or toxic
• Comes from plants, animals or humans (household, Industrial, Municipal or Agricultural Waste)
Sanitary Landfills
• Holes in ground that are lined (to prevent water leeching) and covered
• Gases build up, must have vents
Recycling
• Taking a product at the end of its useful life and turning it into a useable raw material to make another product
• At Catoosa Landfill the following can be recycled: aluminum cans, clear plastic, colored plastic, cardboard, newspaper, mixed paper, used motor oil, used antifreeze, used car batteries for FREE
Green Power
• using alternative means to obtain energy that does not harm the environment
Such as:
• solar power
• wind power
• hydroelectric power