ecology: study of how organisms - engineers' class · ecology: study of how organisms interact...
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Ecology: Study of how organisms
interact with each other and with their
non-living surroundings.
Eco - is from the Greek word “Oikos” for
house
Levels of organization in nature.
The shaded portion is the five
levels that ecology is based upon.
The
Nature of
Ecology
Levels of study in Ecology:
Organisms – single animal
Populations – same species
Communities – pop’ns living
together
Ecosystems – community +
physical environment
Biosphere – all the earth’s
ecosystems
1. Abiotic factors –consists of non-living
components such as water, air, nutrients,
rocks, heat, and solar energy.
2. Biotic factors – consists of living biological
components such as plants, animals, and
microbes.
Producers (autotrophs)
- they make the nutrients they need from compounds and energy obtained from their environment
On land – producers are green plants
On fresh water or marine – algae and aquatic plants
On open water – major producers are phytoplankton
Consumers (heterotrophs)- These cannnot produce the nutrients they need through
photosysnthesis or other processes.
* Types of Consumers
• 1. Primary Consumer
• (Herbivores) – plant eaters or animals that eat producers, feeding mostly on green plants.
• (Carnivores) – animals that feed on the flesh pf other animals.
• 2. Secondary Consumer – feed the flesh of the Herbivores.
• 3. Tertiary Consumer – feed on flesh of other carnivores.
• 4. Omnivores – can eat plants and other animals.
Decomposers – consumers that release
nutrients from the dead bodies of plants and
animals and return them to soil, water, and
air for re-use by producers.
Detritus feeders / detrivores – feed on the
wastes or dead bodies of other organisms
Food chains – sequence of organisms
which is a source of food for the next.
Food webs – most species participate in
several food chains (they don’t just eat
one thing!).
Trophic levels
› each step in the flow of energy through an
ecosystem (feeding level)
1. Atmosphere (Air)
2. Geosphere (Rock, Soil, Sediment)
3. Hydrosphere (Water)
4. Biosphere (Living Things)
1. Atmosphere
- thin spherical envelope of gases surrounding the earth’s surface.
* Layers of Atmosphere:› Troposphere 11 miles above sea level Contains majority of air we breathe (78%v Nitrogen, 21%v
Oxygen, 1%v Water Vapor, Carbon Dioxide and Methane known as Greenhouse gases.Greenhouse gases – absorb and release energy that warms the lower atmosphere.
› Stratosphere 12-30 miles above sea level Lower portion holds ozone layer which filters out harmful UV
radiation. Allows life to exist on earth
1. Hydrosphere
- Consists of all water on or near the earth’s surface.
- Oceans covers 71% of the globe and contain 97% of the earth’s water.
* Compostion:› Liquid Water On the surface and underground
› Ice Polar ice, icebergs, and permafrost (ice in frozen soil)
› Water Vapor
1. Geosphere (land sphere)
- Upper portion contains non-renewable resouces
(fossil fuels, and minerals) and renewable
resources (soil chemicals organisms need to live,
grow, and reproduce.
* Compostion:› Core
› Mantle
› Crust
Life is sustained by the flow of energy
from the sun through the biosphere,
the cycling of nutrients within the
biosphere, and gravity.
Biogeochemical cycles – global cycles
recycle nutrients through the air, land
and water
Cycles are driven directly or indirectly by
solar energy and gravity
Hydrologic cycle (H2O)
Carbon cycle
Nitrogen cycle
Phosphorus cycle
Hydrologic cycle – collects, purifies, and
distributes supply of water.
Hydrologic Cycle can be viewed as a
cycle of natural renewal of water quail
Water withdraw from lakes and streams
Clear vegetation
Construct impervious surfaces
Modify water quality by adding nutrients
Based on Carbon Dioxide
Terrestrial producers remove
CO2 from the air; aquatic
producers remove it from the
water.
Through photosynthesis,
Converts to carbohydrates.
O2 consuming producers
respire,breaking carbo-
hydrates back to CO2.
CO2 not released until burned.
Clear trees and other plants, often times
permanently
Burning fossil fuels and wood
Increased CO2 in the troposphere
enhance natural greenhouse effect
Results in global warming
Atmosphere’s most abundant
element.
Bacteria help recycle nitrogen.
Nitrogen cannot be used by plants
and animals without bacteria’s help.
Ammonia not taken up by plants
Toxic to plants
Usable by plants
Waterlogged
soil
Add large amounts of nitric oxide by burning fuel
Gas converted to nitrogen dioxide gas and nitric acid (acid rain)
Add nitrous oxide through anaerobic bacteria breaking down livestock wastes (global warming).
Release nitrogen stored in soils and plants by destroying forests, grasslands and wetlands.
Add excess nitrates for agriculture Remove nitrogen from topsoils through
harvesting various crops
Fig. 4-33 p. 82
Slow
Bacteria not a major player
Washes from the land into
streams, then the sea.
Can be deposited as sediment
and remain for millions of
years.
Often a limiting factor for
plant growth on land.
Also limits growth in lakes
And streams because
phosphate salts are only
slightly soluble in water.
We mine large quantities of phosphate
rock to make inorganic fertilizers.
We reduce the available phosphate in
tropical soils by clearing tropical forests.
We disrupt aquatic systems with
phosphates from runoff of animal wastes
and fertilizers, and sewage systems.