Download Unit V

UNIT V:The Organism and Its
Environment
Are Humans fully Integrated into
the Biosphere?
(Obj. 1,4)
The Scope of Ecology
1. Ecology: “oikos”-home, house; “-logy”-study of (1866)
2. Study of how living things interact with each other and
with the physical environment
3. Modern ecology not just descriptive, also predictive
4. One goal of ecology is to develop models that explain
and predict the abundance of populations.
(Obj. 1,4)
Levels of Ecological Organization
1.
2.
3.
4.
1
(Obj. 2,3)
Abiotic components of
Ecosystems
1. WATER
2. SUNLIGHT
3. OXYGEN
4. TEMPERATURE
5. SOIL
Biotic Components of
Ecosystems
(Obj. 2)
•All the living parts of an
ecosystem
•Prairie dogs, hawks, snakes,
grasses, seeds, berries,
worms, bacteria, fungi
•??? Name one in your
environment ???
•??? How do abiotic and
biotic differ ???
(Obj. 5)
Biotic Components of Ecosystems
1. Autotrophs (producers)
•
Make their own food
•
Manufacture organic nutrients for all organisms
•
Green plants and algae carry on photosynthesis
•
Some bacteria are chemoautotrophs
2. Heterotrophs (consumers)
•
Cannot make their own food (need outside source of nutrients)
•
Herbivores--eat plants and/or algae (name some ???)
•
Carnivores--eat other animals (name some ???)
•
Omnivores--eat plants and animals (YOU ???)
2
(Obj. 5)
Biotic Components of Ecosystems
3. Decomposers
• Break down wastes and dead organisms and
return raw materials to the environment
• Bacteria and fungi (molds, mushrooms)
• Obtain energy for own needs and return simple
molecules back to environment to be used by
other organisms (producers)
• Detritus: partially decomposed matter
(Obj. 5,6)
Energy Flow and Nutrient Cycling
Food chain
Food web
Trophic level
(Obj. 7)
Energy Balances in Ecosystems
***NET ENERGY LOSS***
Solar energy
100%
Plants
55%
Herbivores
10%
Carnivores
3
(Obj.5-6)
Grazing and Detrital Food Webs
(Obj.6)
Energy Flow
• Trophic Levels
– A trophic level is composed of all the organisms
that feed at a particular link in a food chain.
– Example of a food chain
leaves
caterpillars
tree birds
hawks
(Obj. 6,7))
Ecological Pyramid
BIOMASS
# organisms X weight
4
(OBJ. 1,2,3 P.2)
PHOTOSYNTHESIS
SOLAR ENERGY + 6 CO2 + 6H2O
C 6 H 120 6 + 6O2
CELLULAR RESPIRATION
C6H120 6 + 6O2
6CO2 + 6H2 O + ENERGY
(ATP)
Photosynthesis & Cellular
Respiration
(Obj. 8,9, p.2)
POPULATION
• All the members of one species in a particular area
• Population Density= # of individuals
unit area
• Population Distribution: uniform, clumped, random
• Changes in Population Size
– Growth Rate = Per capita rate of increase
– Example:
A population has 1000 members
Birth rate = 30 / year
Death rate = 10 /year
The growth rate per year will be:
30 - 10 / 1000 = 0.02 = 2.0% per year
5
(Obj. 8,9, p.2)
Patterns of Population Growth
•
Exponential growth
1. “J” shape
2. Lag phase
3. Exponential phase
•
Carrying Capacity
1. “S” shape
2. Exponential growth
3. Deceleration
4. Biotic effects
5. Stable equilibrium
Fig. 33.3
(p.2, Obj. 9)
Survivorship Curves
I: death later
II: death unrelated to age
III: death early
(p. 3, Obj. 1,2)
Human Population Growth
• World population approx. 6 billion
• Approximately 225,000 people are added to
the world’s population every day.
• Approximately 82 million people are added to
the world’s population every year.
• Current doubling time is 56 years
• US population growth currently 0.6%
• US population around 285 million in 2001
(4.75% of world population)
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(p.3)
World Population Growth
MDCs= North America, Japan,
Europe, Australia
LDCs= Latin America, Africa, Asia
Environmental Impact
World Population: MDCs= 22%; LDCs= 78%
Hazardous Waste: MDCs= 90%; LDCs= 10%
Fossil fuels: MDCs= 60 %; LDCs= 40%
Metals: MDCs= 80%; LDCs= 20%
Paper: MDCs= 75%; LDCs= 25%
(p. 3, Obj.3)
Fig. 36.1
(p. 3, Obj. 4)
Reduction in Human Mortality
•Medical advances
•Standard of living
•Technological advances
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(p. 3, “Finally” Obj. 1)
What is Pollution?
•Pollution: a change to the environment that has
a negative effect on living things
•Pollutants: a substance or condition that
contaminates air, water or soil; can be artificial
(pesticides, detergents,CFC’s, fertilizers, acid
rain), or naturally occurring (oil, CO2, goose poop);
heat and uncontained radioactivity also; typically
a waste product.
Air Pollution
Acid deposition: burning of fossil fuels releases sulfur
dioxides and nitrogen dioxides into air; combine with water
vapor to create sulfuric acid and nitric acids (OW!!); dissolve in
rain or snow= acid rain
Ozone Depletion: Ozone layer is layer of upper atmosphere
(thin to begin with)--protects Earth from UV radiation; Late
1970’s= hole in layer (CFCs); agreement in 1990; believe
ozone layer will recover if ban stays in place.
Ozone Pollution: O3=photochemical smog; gases from cars,
trucks, etc. react with sunlight to form ozone; toxic
Greenhouse Effect: water vapor, CO2, other gases allow
sunlight to enter the earth, but prevent heat from escaping;
trapping of heat near the Earth’s surface;
Global Warming: increased CO2 in atmosphere; 1800s-280ppm; 2000s--350ppm;
Why you need to ask questions
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Water Pollution
•Agriculture-fertilizer runoff; animal waste; pesticides
•Salt--changes species survivability
•Sewage--O2 depletion in lakes, disease-causing bacteria
•Heavy metals--lead, mercury, arsenic, tin, etc.
•Industrial wastes--heavy metals, pesticides, organic solvents
•Acid rain and Heat
•Biological Magnification: as a pollutant enters the food
chain, it gets more concentrated as it moves up the food
chain (industrial waste not decomposed--stays in organism;
DDT, PCBs--lead to health problems)
Mud
water
plant
fish
bird
human?
Extinction
What is it? The disappearance of all members of a species
from Earth (natural process-earthquakes, volcanos)
Human Activities that cause Extinction
•Habitat Destruction: forests, wetlands
•Poaching: illegal killing of animals (pets, pelts, teeth, claws)
•Pollution: air, water, soil; health problems
•Exotic species: outcompete native species; no natural
enemies
•Overfishing/hunting: don’t allow recovery time
Protecting Species: captive breeding, laws and treaties,
habitat preservation
Non-Native Species
Nene goose
Japanese honeysuckle
Mongoose
European Starling
Wild boar
Garlic mustard
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