Ecology Unit- part 2

Modified by Beth Roland Jacobs Fork Middle School

All living organisms need certain elements/compounds for life processes– Ex: your cells need

Carbon,Hydrogen,Oxygen,Phosphorus,Nitrogen & Sulfur in order to live and reproduce (make more cells)

Cycles in nature keep these elements “moving” from organisms to organism (and sometimes into the atmosphere)

Biogeochemical Cycles(Matter moving through the environment)

Biogeochemical Cycles(Matter moving through the environment)

The flow of a nutrient from the environment to living

organisms and back to the environment

Main reservoir for the nutrient is in the environment

Transfer rates to and from reservoir are usually lower

than the rates of exchange between and among

organisms.

Matter is recycled through an ecosystem – not one way

flow

Three Categories

Hydrologic cycle

– Water

Atmospheric cycles

– Nitrogen and carbon

Sedimentary cycles

– Phosphorus and sulfur

CYCLES IN NATURE

Carbon Cycle

Carbon moves through the atmosphere

and food webs on its way to and from

the ocean, sediments, and rocks

Sediments and rocks are the main

reservoir

Carbon Cycle

photosynthesisTERRESTRIAL

ROCKS

volcanic action

weathering

diffusion

Bicarbonate, carbonate

Marine food webs

Marine Sediments

Atmosphere

TerrestrialRocks

Soil WaterPeat, Fossil

Fuels

Land Food Webs

Carbon in the Oceans Most carbon in the ocean is dissolved

carbonate and bicarbonate Ocean currents carry dissolved carbon

Carbon in Atmosphere Atmospheric carbon is mainly carbon

dioxide Carbon dioxide is added to

atmosphere– Aerobic respiration, volcanic action,

burning fossil fuels, decomposition of organic materials

Removed by photosynthesis

Nitrogen Cycle Nitrogen is used in amino acids and nucleic acids

(all living organism need nitrogen to make

proteins)

Main reservoir is nitrogen gas in the atmosphere

Decomposers are vital to convert ammonia into:

1. usable nitrites & nitrates for plants (nitrogen fixation)

2. nitrogen gas (denitrification = puts it back into the atmosphere)

Phosphorus Cycle Phosphorus is part of phospholipids and all

nucleotides

– What are these? The basis of all DNA and cell

membranes

It is the most prevalent limiting factor in

ecosystems

Main reservoir is Earth’s crust; no gaseous

phase (it never enters the atmosphere – like

carbon and nitrogen)

Phosphorus Cycle

GUANO

FERTILIZER

ROCKS

LAND FOOD WEBS

DISSOLVED IN OCEAN

WATER

MARINE FOOD WEBS

MARINE SEDIMENTS

excretion

weathering

mining

agriculture

uptake by autotrophs

death, decomposition

sedimentation setting out leaching, runoff

weathering

uplifting over geolgic time

DISSOLVED IN SOILWATER,

LAKES, RIVERS

uptake by autotrophs

death, decomposition

Chapter 3 – Communities & Biomes

Vocabulary to Know:– Limiting Factor– Succession

Primary Secondary

– Climax Community

Community

All the populations that live together in a

habitat

Habitat is the type of place where

individuals of a species typically live

Type of habitat shapes a community’s

structure

Biogeography

The study of the distribution of

organisms and the processes

that underlie distribution patterns

Factors that Affect Distribution

Geologic history

Topography

Climate

Species interactions

Climate

Average weather condition in a region

Affected by:

– amount of incoming solar radiation

– prevailing winds

– elevation

Rotation and Wind Direction

Earth rotates faster under the air at the equator than it does at the poles

Deflection east and west

Seasonal Variation Northern end of Earth’s axis tilts toward

sun in June and away in December

Difference in tilt causes differences in

sunlight intensity and day length

The greater the distance from the

equator, the more pronounced the

seasonal changes

Ocean Currents Upper waters move in currents that distribute

nutrients and affect regional climates

Rain Shadow

Air rises on the windward side, loses

moisture before passing over the mountain

Biomes

Regions of land characterized by

habitat conditions and community

structure

Distinctive biomes prevail at certain

latitudes and elevations

Biomes

Population Size Factors that affect:

– Natality– Mortality/Fatality– Immigration – Emigration

                                                    

Population Density

Environmental Limits on populations

Density-dependent– Disease– Food– Parasitism– Predation– Competition

Intraspecific Interspecific

Density-independent– Temperature– Storms– Floods– Drought– Habitat Disruption

Organism Interactions Limit Populations

Predation Competition

– Both types Parasitism Crowding/stress

Chapter 5: Diversity & Conservation

Importance to nature

Importance to people– Oxygen– Diet– Medicines

Loss of Diversity

Threatened Species

Endangered Species

Extinction of Species

Threats to Biodiversity Habitat Loss Habitat Fragmentation

– Biotic Issues– Abiotic Issues

Habitat Degradation– Air Pollution– Water Pollution– Land Pollution

Exotic Species Non-native

organisms that “move-in” to a particular area

There can be a lack of competitors = exponential growth

Can take over the niches of native species

Example: Page 124

Conservation Sustainable use:

– Use what you need, but don’t damage the ecosystem

Is this a good example of sustainable use?

Humans & The Environment

Ozone (O3) Depletion

– O3 forms a “good layer” around the Earth

– CFC release is breaking down the protective ozone layer

– UV rays increase skin cancers & other cell mutations to plants & animals!

How is Acidity Measured? When we observe acid

rain, acidity is measured in units called pH.

The pH scale is from 0 to 14– pH 7 indicates neutral– higher pH numbers =

alkalinity (base)– smaller numbers = acid

We’ll do more on pH in the “Biochemistry” chapter

Natural Acid Precipitation CO2 combines with

water to form a weak acid H2CO3 (carbonic acid)

But we are adding to the problem…– by adding nitric and

sulfuric acids

Look at the “clean rain” – it’s already slightly acidic???

Effects of Acid Precipitation• In Japan, rain which registers pH 5.6 or less is considered acid rain;

some 80-90% of the rain that falls in Japan in a year is acid rain. • In Japan, acid rain with acidity equal to lemon juice has been

observed at Mount Tsukuba in 1984 (pH 2.5) and at Kagoshima in 1987 (pH 2.45). The problem is even more serious in North America and Europe. In those regions, forests are withering and lakes becoming uninhabitable to fish, and stone structures such as buildings and bronze statues are being damaged by corrosion.

1970 1985

Humans & The Environment

Global Warming– “The Greenhouse Effect”

– Fossil fuels give off lots of CO2

– This builds a blanket around the earth– It is predicted that the Earth temp. will

increase ~50C before 2050 = Ice age????

Carbon Dioxide Increase

Carbon dioxide levels fluctuate seasonally

The average level is steadily increasing

Burning of fossil fuels & deforestation are

contributing to the increase

Greenhouse Effect

Greenhouse gases impede the escape

of heat from Earth’s surface

Global Warming Long-term increase in the

temperature of Earth’s lower

atmosphere

Other Greenhouse Gases

CFCs - synthetic gases used in

plastics and in refrigeration

Methane - produced by termites and

bacteria

Nitrous oxide - released by bacteria,

fertilizers, and animal wastes