Unit 2 Ecology

Chapters 3-6

What to study

Chapter 3: What is ecology? p.63 Levels of organization p.64 Energy flow – sec.2 Cycles of matter – sec.3

What to study

Chapter 4: Climate

& Greenhouse effect - sec.1 Biomes - sec.2 Water ecosystems - sec.3

What to study

Chapter 5: Population growth p.120 Limits to growth p.125-127

Chapter 6: Human activities affect on biosphere- sec.1 Resources – sec.2 Biodiversity – sec.3

Ch 3 The Biosphere

What is Ecology?

Study of interactions btwn organisms and organisms and btwn organisms and their surroundings.

The Biosphere The entire planet! Incl:

-8 kilometers above surface to

11 kilometers below ocean’s surface

Abiotic vs. Biotic factors

Abiotic =

Non-living factors organisms interact with in environment

Biotic =

Living factors

In what ways are non-living things essential to organisms?

Levels of organization Individual organism Population Communities Ecosystem Biome Biosphere

Energy Flow

Producers =

Autotrophs

Use sun, other inorganic nutrients to make organic material – food.

Make their own food.

Consumers =

Heterotrophs

Must get energy from other organisms.

Cannot make their own food.

Types of consumers Herbivores Carnivores Omnivores Detritivores Decomposers

Light vs. no light

Photosynthesis -

Autotrophs use light energy to power chemical rxns that turn CO2 & H2O into carbohydrates

Chemosynthesis –

Autotrophs use energy from chemical bonds not light

Food chains & webs

Food Chain - Energy stored by producers passing

through an ecosystem Energy flows one way in ecosystemsFood web – More complex than chain Links all food chains together in

ecosystem – can be confusing

Ecological Pyramids Amount of energy, mass in ecosystem

Three pyramids Energy

Amount available at each level Biomass

Grams of matter per unit area Numbers

How many are there?

Cycles of matter Water cycle Carbon cycle Nitrogen cycle Phosphorus cycle

The Water Cycle Energy flows one-way in ecosystems but matter

is recycled.Water cycle includes: Evaporation Transpiration Condensation Precipitation Runoff Seepage Root uptake

Nutrient Cycles

The carbon cycle (see p. 77) Carbon found many places Atmosphere – CO2 gas

Oceans – dissolved CO2

Land – organisms, rocks, soil Underground – coal, petroleum,

CaCO3

Nutrient Cycles

The Nitrogen Cycle (see p.78) All organisms need N – make amino

acids Cycles through soil, tissues N2 gas =78% of atmosphere

In wastes as nitrates(NO3-) &

nitrites(NO2-), ammonia(NH3)

Nitrogen Fixation

Bacteria convert N2 gas into ammonia This bacteria lives in soil & on roots of

plants such as legumes Plants use from soil Consumers eat, reuse Decomposers return it to soil

Nutrient Cycles

The Phosphorus Cycle Needed for DNA, RNA Not as common Not in atmosphere In rock, soil minerals, ocean sediment Cycles btwn soil-organisms

Chapter 4Ecosystems & Communities

Climate vs. Weather

Weather:

Everyday condition of the Earth’s atmosphere at a given place/time

Climate:

Average year after year conditions of temp. & precip.

The Greenhouse Effect Natural Heat retained in the Earth’s

atmosphere by a layer of gasses Consists of CO2, methane, water

vapor & other gasses Named for a “greenhouse”

Latitude & Climate The sun’s heat hits the Earth’s surface

at different angles throughout the year Earth has three climate zones

Climate Zone:

Result of the differences in latitude and angle of heat from sun

Earth’s Climate Zones Polar Temperate Tropical

Ecosystem Characteristics Biotic factors Abiotic factors

Give you:

Habitat – area where organism lives

Niche –

Total use of organisms’ biotic, abiotic factors how it fits in an ecosytem

Community interactions

1. Competition

Use resources to survive in same place, at same time

Competitive exclusion

No 2 species in same niche at same time

Community interactions

2. Predation

3. Symbiosis Mutualism Commensalism Parasitism

Ecological Succession Changes in a community over time Changes occur due to disturbances Disturbances can be natural or man-

made

Primary Succession Occurs on bare land Pioneer plants (lichens, mosses)

Ecological Succession

Secondary Succession Occurs in established communities

after disturbances

Biomes Communites covering large area certain soil, climate conditions certain animals, plants Several across the world

Ch 5 Populations Population Density

# of organisms in a unit area Population Growth

Affected by 3 things

-births

-deaths

-# of organisms leaving, entering pop.

Population Growth Exponential Growth

-Reproduction constant

-unlimited recourses

-has j-shaped curve Logistic Growth

-pop. Grows or stops depending on resources

-has s-shaped curve

Carrying Capacity # of organisms a given environment

can support Logistic growth will level off at carrying

capacity

Limits to growth

What’s a limiting factor?

Something which affects a population in some way. May cause the population to decrease/increase.

Competition Predation Parasitism Disease

Factors Affecting Growth

Density Dependent Factors A limiting factor that depends on

population size

Density Independent Factors A limiting factor affecting all

populations regardless of size

Disturbances Natural Man-Made