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

• \\Hhsadms1\vol1\Users-Teachers\tbicknell\Honors Biology\Unit 4 - Ecology\Concepts_in_Nature__Animal_Predators_and_the_Balance_of_Nature.asf

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