Ecology Unit- part 2 Modified by Beth Roland Jacobs Fork Middle School.
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Transcript of Ecology Unit- part 2 Modified by Beth Roland Jacobs Fork Middle School.
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