ECOLOGYECOLOGY

CHAPTERS CHAPTERS 3,4,5 & 63,4,5 & 6

What is Ecology? 3.1What is Ecology? 3.1• Ecology – the scientific study

of interactions among organisms and between organisms and their environment or surroundings.

• Biosphere – contains the combined portions of the planet in which all life exists

–Includes land, water and air

–Extends 8 kilometers above Earth’s surface to a depth of 11 kilometers below the ocean’s surface

• Levels of Organization –

–Species – groups of organisms that can breed and produce fertile offspring

–Populations – groups of individuals that belong to the same species and live in the same area

–Communities – groups of populations

–Ecosystems – groups of populations along with their nonliving, or physical, environment.

• Biomes – Groups of ecosystems

So...So...

• A flock of birds….

ecosystem, community, population, or individual?

• A valley of trees, a lake, clouds, plants, & animals….

ecosystem, community, population, or individual?

• A coral reef with many different species of animals and plants….

ecosystem, community, population, or individual?

• A stand of aspens….

ecosystem, community, population, or individual?

Let’s Practice

Species

Population

Community

Ecosystem

Ecology MethodsEcology Methods• Observing – …”what species

lives here?”

• Experimenting – …”what would happen if we reintroduced wolf species back into Yosemite National Park?”

• Modeling - …”what can computer models tell us about the impact of global warming?”

Let’s look at some satellite

observations(page 66 of your

text)

Cycles of Matter 3.3Cycles of Matter 3.3• Unlike energy, matter is

recycled within and between ecosystems through biogeochemical cycles.

• Water Cycle–Cycles through the ocean, land and atmosphere

–Enters atmosphere as gas (water vapor) through evaporation (from oceans) and transpiration (from plant leaves)

• Vapor condenses and falls back to Earth (precipitation) into rivers, streams and ground water and is reabsorbed by plant roots.

• Carbon Cycle –

–Essential nutrient for all organic compounds

–Less than 1% is cycled

–Enters the atmosphere as CO2 from respiration, volcanic activity, burning of

–fossil fuels, decomposition of organic matter.

–Plants take in CO2 to make carbohydrates.

–Carbohydrates are passed along the food chain and reenters the atmosphere

• Nitrogen Cycle

–Organisms need nitrogen to make proteins

–Nitrogen exists in the atmosphere (78% of our atmosphere); in waste products (ammonia, nitrates, nitrites)

–Bacteria in the soil can take gaseous nitrogen and convert it to ammonia for use by plants (nitrification)

–Dead organisms have their nitrogen returned to the soil through decomposers in a process called denitrification

• Phosphorus Cycle

–Needed by organisms to make DNA and RNA

–Found primarily on land in rocks, soil and ocean sediments

Complete the chart

Cycles of Matter Enters the Atmosphere Leaves the Atmosphere

Water

Gas; water vapor – evaporation from oceans etc.; transpiration – plants

Vapor condenses; falls as precipitation

Carbon

CO2 from RSP,

volcanic activity, burning of fossil fuels, decomposition of organic matter

Taken in by plants for PSN; Carbohydrates passed through food chain

Nitrogen

Makes up 78% of atmosphere; in waste productsDecomposers return it through denitrification

Bacteria converts it to ammonia for use by plants during nitrification

• Greenhouse Effect – The natural situation in which heat is retained by a layer of greenhouse gases (CO2, methane and water vapor)

Stratosphere

Troposphere

What Shapes an What Shapes an Ecosystem 4.2Ecosystem 4.2

• Biotic factors – all living members of an ecosystem

• Abiotic factors – wind, soil, sunlight, temperature, precipitation, humidity

• Niche – an organism’s occupation in its habitat

Biotic or Abiotic?Biotic or Abiotic?

• Clouds, weather, humidity, air temperature

• Spider, spider’s web

Biotic or Abiotic?Biotic or Abiotic?

Biotic or Abiotic?Biotic or Abiotic?

•Coral, algae, bacteria

Biotic or Abiotic?Biotic or Abiotic?

•Rock, snow or rain, ice, altitude

• Ecological Succession – the gradual change in an ecosystem when old organisms die and are replaced by new ones.

–Primary succession – occurs on land surfaces where no soil exists; volcanic eruptions, glacier melts; first species to appear are the pioneer species (usually lichens)

• Secondary succession – follows primary succession; example: when farm land is abandoned or when wildfires burn forests

• Community Interactions

• Competition

• Predation

• Mutualism

• Parasitism

• Commensalism

–Competition – occurs when organisms attempt to use the same resource in the same place and the same time; often results in competitive exclusion principle which states that no two species can occupy the same niche in the same habitat at the same time.

–Predation – an interaction in which one organism (predator) captures and feeds on another (prey)

–Symbiosis – any relationship in which two species live closely together

–3 types:

•Mutualism (+,+) – both species benefit from the relationship (flowers and insects; acacia and ants)

•Commensalism (+,0) – one member benefits and the other is neither helped nor hurt (barnacles and whale; sharks and remora)

•Parasitism (+,-) – one member benefits and the other is harmed (ticks and dogs)

Let’s Practice

Vocabulary

Let’s look at a real example

Brown-headed cowbird

Willow Flycatcher

Let’s do a lab using

predator/prey relationships

Biomes 4.3Biomes 4.3• Biomes – a particular

physical environment that contains a characteristic assemblage of plants and animals.

Using your textbook pp. 98 – 112, answer the “Where Am I?”

questions on the handout

Populations 5.1Populations 5.1• Characteristics include

–geographic distribution – the area inhabited by a population

– density – the number of individuals per unit area

–growth rate

• Population Growth – determined by

–Number of births

–Number of deaths

–Number of immigrants/emigrants

• Exponential Growth

–Occurs when the individuals in a population reproduce at a constant rate.

–Under ideal conditions with unlimited resources, a population will grow exponentially

–Graphs of this growth have a “J” shape

Exponential Growth

• Logistic growth–Occurs when a population’s growth

slows or stops following a period of exponential growth.

–As resources become less available, the growth of a population slows or stops.

–Graphs of this growth show an “S” shape; the top horizontal line represents the “carrying capacity” of the environment for a species.

Logistic Growth

0

20

40

60

80

A B C D E F

Time

Nu

mb

er

of

ind

ivid

uals

• Boom and Bust growth

–Occurs when under ideal conditions with unlimited growth followed by sudden collapse.

–Graphs of this growth show peaks and valleys.

Boom & Bust Population Boom & Bust Population CurveCurve

Jan Mar May Jul Sep Nov

Pop

ulat

ion

dens

ity

Let’s Practice Graph

Reading

Human Population Human Population Growth 5.3Growth 5.3

• Demography – study of human populations; studied using:

–Birth rates

–Death rates

–Age structure

• Demographic Transition – a dramatic change in birth and death rate

• Age structure – models used to predict future growth

SwedenSweden

MexicoMexico

United StatesUnited States

Limits to Growth 5.2Limits to Growth 5.2• Limiting factor is a

factor that causes population growth to decrease

–Density-dependent

–Density-independent

• Density-Dependent Factor – a limiting factor that depends on population size–Competition–Predation–Parasitism and Disease

• Density-Independent Factor – a limiting factor that affects all populations, in similar ways, regardless of population size

–Weather

–Seasonal cycles

–Dams

–Clear cutting

Let’s Practice Age

Distribution Graph

Reading

Let’s Practice Graph

Reading One More Time!

Role of Climate 4.1Role of Climate 4.1• Climate – the

average, year after year conditions of temperature and precipitation in a particular region.

Weather

– day to day conditions

•Sunlight – energy from the sun drives Earth’s weather and helps determine climate

• Effects of Latitude on Climate–Earth’s shape causes the sun’s energy to strike at different angles

–The difference in latitude and the angle of the sun’s rays results in 3 climate zones

•Temperate – between poles and tropics; climate varies widely

•Tropical – near equator; climate is always warm

•Polar – top and bottom of Earth; climate is always cold

• Heat transport in the Biosphere

–Uneven heating and cooling create winds and ocean currents

–Land masses (especially mountain ranges) cause warm, moist air to rise, condense and rain on one side of the mountain; the other side is usually dry (rain shadow)

Let’s Practice

PolarTropical

Temperate

Temperate

Energy Flow 3.2Energy Flow 3.2• Producers – organisms that can

make their own food:

–Chemotrophs – make food from inorganic chemical compounds

–Autotrophs – make food from sunlight through photosynthesis

• Consumers – (heterotrophs)–Herbivores – eat plants (deer)

–Carnivores – eat animals (lion)

–Omnivores – eat both plants and animals (humans & raccoons)

–Detritivores – Feed on plant and animal remains (crabs)

–Decomposers – break down organic matter and return it back to the Earth (bacteria and fungi)

Feeding RelationshipsFeeding Relationships• Energy flows through an

ecosystem in one direction from the sun (or inorganic compounds) to the autotrophs to the various levels of consumers.

• Food Chain – a series of steps in which organisms transfer energy by eating and being eaten.

• Food Web – Shows the feeding relationships among various organisms in an ecosystem.

–It forms a network.

–It is more accurate than a food chain.

• Trophic Levels – each step in a food chain or web–1st level – producers–2nd and up – consumers (1o, 2o, 3o, etc. are referred to as primary, secondary, tertiary consumers)

Let’s Practice

Producer Primary Consumer

Secondary Consumer

Tertiary Consumer

• Ecological Pyramids – a diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or web.

–Energy pyramid – amount of energy

•10% Law – says that only 10% of the available energy is transferred to the next trophic level.

–Biomass pyramid – amount of living tissue at each trophic level

–Pyramid of numbers – number of organisms at each trophic level

Let’s Draw

500,000 kc

50,000 kc

5,000 kc

500 kc

Producers

Primary consumers

Secondary consumers

Tertiary consumers

Complete “What is a

Food Pyramid?”