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Ecology is The study of the distribution and abundance of organisms, AND the flows of energy and materials between abiotic and biotic components of ecosystems. Ecology is an integrative/ interdisciplinary science -Understanding of the biological (biotic) and physical (abiotic) sciences
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The study of the distribution and abundance of organisms,
the flows of energy and materials between abiotic and biotic components of ecosystems.
-Understanding of the biological (biotic) and physical (abiotic) sciences
-Provides a context for the reductionist sciences in biology
-Closely tied to genetics and evolution
-Ecology can be studied at different spatial and temporal scales
-Includes the role of humans in their environment (= global change)
Salinity important for water organisms (high salt, low salt). Microbes have contractile vacuole to pump out excess water. Fishes have adaptations to extreme salinity.
pH value is important, for ponds and streams, the pH value can change whether plants absorb CO2 or give off CO2. (more acidic)
a. Hides from predators.
b. Example: English Peppered Moth
a. Advertises noxious trait
b. Example: Monarch Butterfly
1. Mullerian Mimicry: when two unpalatable species mimic each other in the same habitat.
2. Batesian Mimicry: palatable species mimic unpalatable species.
1. Tick on a coyote
2. Tapeworm in a dog
3. Flea on a cat
1. Cattle egrets and cattle in field
1. Acacia ants and acacia tree
2. Termites and gut protozoa
3. Legumes and nitrogen-fixing bacteria
Survival and reproduction
unit of natural selection
unit of evolution
species diversity, trophic dynamics
Energy flux and
nutrient cycling, primary productivity
includes biotic and physical systems
oceans, atmosphere, geology
the processes and conditions provided by ecosystems that are beneficial to humans and other organisms
the processes and conditions provided by ecosystems that are beneficial to humans and other organisms
-- a community of animals and plants interacting with one another and their physical environment
-- includes physical and chemical components such as soils, water, nutrients that support the organisms that live within them, ranging from bacteria to rainforest trees to elephants and humans too
Definition: All the organisms living in a community AND the abiotic factors with which they interact
Scale depends on questions asked
One, small habitat, up to –
Energy flow through trophic levels
Carbon (climate change)
Inorganic nutrients (eutrophication)
1st Law of Thermodynamics
Energy is conserved
energy in from outside sources
passed from trophic level to trophic level
2nd Law of Thermodynamics
Energy transformation is not100% efficient
Ultimately all lost as heat
Trace energy flow
Outside source to heat
Compute energy budgets at each transfer
& dead remains
PHOTO, chemo Autotrophs
1. Primary Producers
2. Primary Consumers
3. Secondary Consumers
4. Tertiary Consumers
5. Decomposers and Detrivores
In ecology, a niche is a term describing the relational position of a species or population in an ecosystem. All living things have their niches. A niche is the role and position of a species in nature. Another way of looking at it is that a niche is basically an organism's "job" in nature. Two different populations can not occupy the same niche at the same time, however. The description of a niche may include descriptions of the organism's life history, habitat, and place in the food chain. The full range of environmental conditions (biological and physical) under which an organism can exist describes its fundamental niche. As a result of pressure from, and interactions with, other organisms (e.g. superior competitors) species are usually forced to occupy a niche that is narrower than this and to which they are mostly highly adapted. This is termed the realized niche.
Cryptic: Concealing form and coloration which enables a species to avoid its natural predators by camouflage. Good examples of this adaptation are the katydid, walking stick and tomato hornworm. The spittlebug secretes a foamy mass to conceal itself on a branchlet. An interesting resident bird of the alpine tundra is remarkably camouflaged by seasonal coloration. During the summer months the plumage is a mottled brownish color. During winter, when the ground is covered with snow, the plumage is snow white.
Two examples of camouflage in San Diego County: A canyon tree frog (Hyla arenicolor) on granodiorite canyan wall (left) and a desert horned lizard (Phrynosoma platyrhinos) on a sandy riverbed.
Bright colorations among the males of some animals (particularly the plumage of birds) gives the male a definite advantage in sexual selection and mate attraction. Mating coloration and behavior of the most "fit" and aggressive males serves to stabilize the population density because only the most sexually select males are able to mate with females of the species.
Left: A male frigatebird (Fregata magnificens) photographed on North Semour Island in the Galapagos Archipelago. The male uses his bright red, inflated throat pouch (gular sac) to attract a female. The male sits in the branches of a tree or shrub and waits for a female to fly over. On sighting a female he turns his head up to expose his red pouch, shakes his wing vigorously and makes a loud, resonating courtship call. If the female is impressed she will land next to him.
Mimicry: One insect (called a mimic) that is perfectly palatable to its predator resembles another insect (called the model) that is quite disagreeable to the same predator. There are actually two types of mimicry: Batesian and Mullerian. Mimicry in which the mimic is essentially defenseless is called Batesian Mimicry. A harmless moth (Aegeria) is a Batesian mimic because it is incapable of stinging another animal, but yet it resembles the yellow jacket wasp (Vespula). Mimicry in which the mimic shares the same defensive mechanism as the model is called Mullerian mimicry. The yellow jacket wasp and bumblebee (Bombus) are Mullerian mimics because they both have bright yellow and black colors and use powerful stings as a defensive mechanism.
Two modes of population growth. The Exponential curve (also known as a J-curve) occurs when there is no limit to population size. The Logistic curve (also known as an S-curve) shows the effect of a limiting factor (in this case the carrying capacity of the environment).
Nonorganic source energy converted to organic chemical energy by autotrophs
Measurement (per unit area per unit time):
Energy (Joules / m2 / yr)
Biomass - organic molecule dry weight (g Carbon / m2 / yr)
Primary production sets the spending limit for the ecosystem’s energy budget
1 % of the available visible light energy is converted to chemical energy by photosynthetic organisms!
A few systems depend entirely on chemosynthetic primary production
Primary production: capture of light energy and its conversion into energy of chemical bonds in carbohydrates by plants, algae, and some bacteria
Primary productivity: rate at which primary production occurs
Gross primary productivity (GPP): the total energy assimilated* by plants through photosynthesis
Net primary productivity (NPP): the total energy assimilated by plants through photosynthesis minus energy used in respiration
NPP represents energy in an ecosystem available to consumers
NPP usually expressed in g/m2/year
* incorporation of any material into the tissues, cells and fluids of an organism
1 Primary producer = Autotrophs that support all other trophic levels by synthesizing sugars and other organic molecules using light energy.
2. Primary consumers = Herbivores that consume
3. Secondary consumers = Carnivores that eat herbivores.
4. Tertiary consumers = Carnivores that eat other carnivores.
5. Detritivores = Consumers that derive energy from
organic wastes and dead organisms.
Ecological pyramid of energy
width of each bar represents the net production of each trophic level
ecological efficiency = % of energy transferred across trophic levels
efficiencies are 20%, 15% and 10% between trophic levels
Trophic efficiency (TE) = % of production transferred from one trophic level to the next
TE less than PE because 2 losses aren’t included for PE:
energy produced by the next lower level but not actually consumed
unassimilated food at the present level (lost in urine, feces)
80-95% of energy is lost between each level – not consumed, not digested, respired
Compounding of loss throughtrophic pyramid explains why food webs usually have only four or five trophic levels
Predators are usually larger than the prey they eat
Limited biomass at the top of an ecological pyramid is concentrated in a relatively small number of large individuals
“Top predators” are particularly vulnerable to extinction
Ratio of net productivity at one trophic level compared to net productivity at the level below.
Ecological efficiencies are 5-20%
Chemical energy in consumer’s food converted to new chemical energy (growth of new consumer biomass)
Amount ultimately determined by:
Efficiency of energy transfer between trophic levels, usually 5-20%
Only 5% to 20% of energy passes between trophic levels
net production of one trophic level becomes the ingested energy of the next higher level
amount of energy reaching each trophic level depends on …
… NPP at the base of the food chain
… efficiencies of energy transfer at each trophic level
Ricklefs Fig. 6.2
primary producers = 15-70% of assimilated energy used for maintenance
herbivores and carnivores = 80-95% of
assimilated energy used for maintenance
Net production efficiency (%)
growth+energy in offspring : assimilated energy
birds < 1%
small mammals = up to 6%
cold blooded animals = 75%
Energy Flow through Ecosystems
1) Assimilation efficiency increases at higher trophic levels
2) Net and gross production efficiencies decrease at higher trophic levels
3) Ecological efficiencies average about 10%
Thus, only about 1% of NPP ends up as production in the third trophic level
Water pollution is a large set of adverse effects upon water bodies (lakes, rivers, oceans, groundwater) caused by human activities. Although natural phenomena such as volcanoes, storms, earthquakes etc. also cause major changes in water quality and the ecological status of water, these are not deemed to be pollution. Water pollution has many causes and characteristics. Increases in nutrient loading may lead to eutrophication. Organic wastes such as sewage and farm waste impose high oxygen demands on the receiving water leading to oxygen depletion with potentially severe impacts on the whole eco-system. Industries discharge a variety of pollutants in their wastewater including heavy metals, organic toxins, oils, nutrients, and solids. Discharges can also have thermal effects, especially those from power stations, and these too reduce the available oxygen. Silt-bearing runoff from many activities including construction sites, forestry and farms can inhibit the penetration of sunlight through the water column restricting photosynthesis and causing blanketing of the lake or river bed which in turns damages the ecology.
Contaminants may include organic and inorganic substances.
Some organic water pollutants are:
insecticides and herbicides, a huge range of organohalide and other chemicals
bacteria, often is from sewage or livestock operations;
food processing waste, including pathogens
tree and brush debris from logging operations
VOCs (Volatile Organic Compounds, industrial solvents) from improper storage
Some inorganic water pollutants include:
heavy metals including acid mine drainage
acidity caused by industrial discharges (especially sulfur dioxide from power plants)
chemical waste as industrial by products
fertilizers, in runoff from agriculture including nitrates and phosphates
silt in surface runoff from construction sites, logging, slash and burn practices or land clearing sites
Oil pollution is a growing problem, particularly devestating to coastal wildlife. Small quantities of oil spread rapidly across long distances to form deadly oil slicks. In this picture, demonstrators with "oil-covered" plastic animals protest a potential drilling project in Key Largo, Florida. Whether or not accidental spills occur during the project, its impact on the delicate marine ecosystem of the coral reefs could be devastating.
One type of air pollution is the release of particles into the air from burning fuel for energy. Diesel smoke is a good example of this particulate matter . This type of pollution is sometimes referred to as "black carbon" pollution. The exhaust from burning fuels in automobiles, homes, and industries is a major source of pollution in the air.
Another type of pollution is the release of noxious gases, such as sulfur dioxide, carbon monoxide, nitrogen oxides, and chemical vapors. These can take part in further chemical reactions once they are in the atmosphere, forming smog and acid rain.
Reduce soil salinity, water tables
Prevent erosion, nutrient leeching
Conserve endangered species, biodiversity
Aesthetics (picnic areas, natural beauty)
Improve water quality (reservoir)
Reestablish area after logging, mining
Cultural heritage issues
Ethics – rights to destroy other species?
Ecosystem stability – food web, nutrient
cycles, mutalism, clean air
Source of medicines or industrial raw materials
Survival of species adapted to that area
Species with high rate of survival
Local species to support local animal populations
Disease resistant strains
Variety of species that naturally grow together.