ecology & the flow of energy in the ecosystem. the study of the interactions of organisms with...
TRANSCRIPT
Ecology & the Flow of Energy in the Ecosystem
The study of the interactions of organisms with one another and their physical environment
Ecology
EcosystemA self-sustaining
collection of organisms and their physical environment
Both biotic and abiotic factors in a large area
Biotic & Abiotic Factors
Biotic =Living
organisms
Abiotic =NonlivingSoil,Air,Water
Energy in Ecosystems
Energy flows into the biological world from the SUN, the ultimate source of all energy.
Producers Producers are
autotrophs… they can make their own food through photosynthesis
Plants, some bacteria and algae
Consumers
Eat other organisms to obtain energy
Example: cows, humans…
Detrivores Organisms that
obtain energy by eating organic wastes or dead bodies.
Ex. Vultures
•http://www.slivoski.com/birding/birds/turkeyvulture.htm
•http://montereybay.com/creagrus/vultures.html
Decomposers Break down organic wastes
(feces, urine, dead leaves or bodies) and cause decay.
Receive energy from every other type
Responsible for the final step in the food chain
Example:Earthworms, maggots, fungi, and some bacteria
How is energy passed along an ecosystem?
Pyramid of Energy
Trophic Levels: Movement of energy
through an ecosystem Levels of energy away
from the sun (ulitmate source of energy)
Who eats who in the food chain
Shown as food chains, webs & pyramids
3rd Trophic Level – animals that feed on plant eaters or other flesh eaters (carnivores) Ex - Tiger
- omnivores eat both plants & animals. Ex - humans
2nd Trophic Level – animals that eat plants (herbivores) Ex - cow
1st Trophic Level – producers/autotrophs Ex - plants
Food Pyramid
On average, only 10% of the energy in any trophic level will be transferred to the next level.
Food Pyramid
Tertiary consumer
Secondary consumer
Primary consumer
Producers
Food Chains & Food Webs
Most animals feed on more than one trophic level and feed on several different species at each trophic level. Making up a food chain and eventually a food web.
Food Chain
ONLY ONE source of food
Less stable
Food WebMore than one
choice of foodSeveral food
chains linked together
More stableMore Common
PopulationEcology
PopulationNumber of
IndividualsSame SpeciesLive together
in one area or place
What dynamics might be involved in predicting population growth?
Population Size Population Growth Rate Carrying CapacityLimiting Factors
Population SizeNumber of
individuals in a population
Growth occurs when the birthrate is greater than the death rate.
Population Growth CurvesExponentialgrowth: Population
increases by a constant proportion per unit of time
At this growth rate the population exhibits a J-shaped curve
Population Growth CurvesLogistic growth: Population increases
rapidly for a period of time, its growth begins to slow, and ultimately, growth stops.
At this growth rate the population exhibits an S-shaped curve.
K (carrying capacity) = maximum population size that an environment can support
K
Factors That Control Population Growth
Populations don’t grow indefinitely because of Limiting factors.
Limiting Factors: Competition Predation Parasitism Crowding Stress Disease
Competition Situation in which
two or more organisms attempt to use the same scarce resource (this could be a food source, a good location for capturing sunlight by plants, a particular nutrient, etc…)
Predation A relationship between two organisms in
which one organism (predator) kills and devours another organism (prey).
Parasitism: The relationship
between two organisms where one organism benefits (parasite) and the other is harmed (host).
Example: Tapeworm You are harmed
because it lives off your intestinal fluids
Segments break off to form a new worm!
Biodiversity The number
of species living within an ecosystem.
How Populations Evolve
Hardy-Weinberg Principle
–The frequencies of alleles in a population do not change unless evolutionary forces act on the population.
–p2 + 2pq + q2 = 1
How Biodiversity Impacts Population Growth
6 forces that cause populations to evolve:
Mutation – ultimate source of all variation Migration – movement of organisms from one
population to another, creates gene flow. Nonrandom mating – when individuals prefer to
mate with others of their own genotype, inbreeding is an example.
Genetic drift – random change in response to their environment.
Natural selection –Survival of the fittest. Extinction- species that have disappeared
permanently.
Organism Interrelationships
Organism Interrelationships: Symbiosis=
a close long term relationship between two or more species
Beneficial: Mutualism=
Both benefit Commensalism=
Only one benefits & other is not harmed or helped
Harmful: Parasitism=
One benefits &
Host slowly harmed
Fungi carbon dioxide moisture
Algae food Oxygen
Mutualism (Both Benefit)
Commensalism
(One Benefits)
Whale unharmedBarnacles Protection from
predators Transportation to
new food sources
Commensalism (One Benefits)
Clown fish dwell among the tentacles of tropical sea anemones. The anemomes are capable of stinging most fishes, but the clown fish possess a special mucous coating that somehow prevents the discharge of the anemone's stinging cells. The fish is protected from predators by the stinging cells.
Parasitism: The
relationship between two organisms where one organism benefits (parasite) and the other is harmed (host).
Example: Tapeworm You are harmed
because it lives off your intestinal fluids
Segments break off to form a new worm!
Cycles
Cycles within Ecosystems Almost everything
within an ecosystem is recycled.
Water, carbon, nitrogen & phosphorus pass from the nonliving environment to living organisms & then back to the environment.
Water Cycle Water is the most
important, non-living component of the ecosystem.
Nonliving cycle: involves condensation, precipitation, & evaporation.
Living cycle: involves plants in a process called transpiration.
Human Impact on the Environment
Human Impact on the Environment
How much trash do you think you throw away?
How many times a day does a person pollute the environment?
How many lakes and forests are killed by acid rain?
Pollution
Pollution is anything potentially harmful that humans add to the environment.
Pollution can drastically damage the health of ecosystems as well as the health of human beings.
Air Pollution
Mainly caused by the burning of fossil fuels.
Many forms:
- Carbon Monoxide
- Nitrogen Oxide
The Ozone Layer Consists of a layer of gas that is
responsible for keeping UV radiation from reaching the earth’s surface.
It is being destroyed by chlorofluorocarbons (CFC’s)
CFC’s found in coolant in refrigerators & air conditioners, and the propellant in aerosol cans.
1 chlorine molecule destroys 100,000 ozone molecules.
Acid Rain Occurs when air
pollutants get mixed with rain in the atmosphere.
The product is sulfuric acid which is falls back to earth in rain and snow.
Pure water has a pH of 7.0 (neutral)
Normal rain has a pH of about 5.6. Acid rain has a pH below the 5.6 Avg. The pH in northeast US is 3.8.
Marble surfaces exposed to acid rain develop a rough "sugary" texture because the calcite grains are loosened as the edges dissolve in the rain water. Column capital volute, Jefferson Memorial, Washington, D.C.
Acid Rain and Our Nation’s Capital
Acid Rain
NaOH
Greenhouse Effect
Caused when sunlight reflected from earth’s surface is trapped as heat by carbon dioxide gas.
Scientists predict an average temperature increase of 1-5 degrees C by 2050.
How does this impact the environment?
ResourcesRenewable resources: Resources that
replenish themselves naturally.
Example:– Trees
Nonrenewable resources: Resources that do not
replenish themselves naturally.
Examples:– Extinct species– Fossil fuels such as oil
and gas
Trees are a renewable resource, but a forest ecosystem is nonrenewable. Why?
New trees can be planted and grown to replace those cut down, but an ecosystem involves a complex web of relationships that are established over very long periods of time.
How pollution effects our Resources
Pollution has led to a rapid draining of fuel supplies.
The known reserves of oil and natural gas will be nearly depleted by the middle of the next century.
Fossil fuels are nonrenewable resources. Nonrenewable resources do not replenish
themselves naturally, whereas renewable resources do.
Solutions to Pollution Reduce pollution by
proper waste disposal and recycling
Conserve nonrenewable resources
Reduce consumption of natural resources
Conserve energy Curbing human
population growth
Waste disposal & Recycling Each year,
Americans generate 153 million tons of garbage. This is dumped into landfills or is burned creating air pollution.
Solutions: Recycle as much as
possible– Aluminum products– Glass containers– Office & school paper– Newspaper– Many plastic materials
Buy products that contain recycled materials
Properly dispose of toxic and hazardous materials– Household insecticides– Oven cleaners– Furniture cleaners– Oil-based paint– Motor batteries & oil
Conserving Nonrenewable Resources
Topsoil for Agriculture The world has lost ¼ of its topsoil due to erosion from clearing of trees and vegetation and cultivating crops.
Ground water (water trapped beneath the soil) Groundwater is being depleted by watering lawns, washing cars, and running fountains. It is also being polluted by poor disposal of chemical wastes.
Species are disappearing. About 1/2 of the world’s tropical rainforests have been destroyed. At this rate, most of the world’s rainforests will be gone in 40 years. It is estimated that 1/5 or more of the world’s species will become extinct, mope than a million species lost, if the rainforests are destroyed.