Ecology
The interactions among organisms
and between organisms and their
environment.
http://www.nearctica.com/ecology/ecology.gif
http://www.scieng.flinders.edu.au/courses/biodiversity/postgrad/biodiversity.jpg
Why study ecology?
• Understanding ecology helps people make
decisions about environmental issues:
– Wildlife management
– Deforestation
– Managing natural resources
http://www.kznwildlife.com/images/mngt_icon.gif
What does ecology involve?
• Biotic factors
– all living organisms
• Abiotic factors
– non-living physical and chemical conditions (water, air,
soil, etc.).
http://www.bio.bris.ac.uk/research/community/
Life Organization
• Subatomic particles
• Electrons, Protons,
Neutrons
• Atoms
• Molecules/Compounds
• Macromolecules
• Organelles
• CELLS
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Tissues
Organs
Organ Systems
Organism
Population
Ecosystem
Biosphere
Ecology Levels
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Individual Organisms
Populations
Communities
Ecosystems
Biosphere
http://www.knowledgebank.irri.org/IPM/appecology/image3.gif
Organism
• Smallest unit of ecological study
• Ecology: What adaptations did an organism
evolve?
http://www.gettysburg.edu/college_life/osa/orgs/acad%20clubs/biosphere/frog.jpg
http://www.uga.edu/srel/Graphics/E.%20Box%20turtle.jpg
Population
• Group of organisms of
the same:
– Species
– Time
– Place
• Ecology: What factors
affect a population?
Communities
• All of the organisms inhabiting a particular
area.
• Ecology: How do populations in a
community interact with one another?
http://www.ufz.de/data/5120
Ecosystems
• Includes both abiotic and biotic factors
• Ex) a coral reef
– Includes water, sunlight, coral, fish species
• Ecology: How do energy and chemicals
flow in an ecosystem?
– Carbon cycle, water cycle, nitrogen cycle
Biosphere
• All Earth’s ecosystems
• Ecology: Focus on global issues = The
effect of climate change on living things.
http://library.thinkquest.org/J002558F/biosphere.jpg
Biosphere Divisions: Habitats
• Habitats: specific environments in which
organisms live
• Due to the differences in abiotic factors:
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Temperature
Soil type
Water availability
Sunlight availability
http://www.les-snats.com/milieu-et-habitat/milieu-habitat.jpg
Sunlight
• Provides warmth, light, and is the primary energy
source.
• Powers photosynthesis: done by producers
– Ex) plants and protists
• That energy is stored in the producers and
consumed by others (energy is transferred)
– (will cover later)
http://oceanworld.tamu.edu/NMEA_Talk/NMEA%20Talk%2020032.jpg
Water
• Essential to all life
• Humans consist of 70% water!
• Water can dissolve gases (oxygen) and salts
which are also important to organisms.
• Organisms evolve ways to regulate water:
– Pines: have thick cuticles
– Lizards: scaly skin
Wind
• Can stir up ponds, lakes, and streams (bring
nutrients up from bottom)
• Disperse pollen and seeds
• Affect organisms
– Flagging of trees
http://southadventure.tripod.com/flag_tree.jpg
CLIMATE
• Energy from the sun warms the surface of the Earth
• Temperature differences at different latitudes
– Results from angle of incoming sunlight
• Equator receives most direct sunlight, poles least
• So what causes the seasons to change?
Population & Community
Ecology
http://www.nearctica.com/ecology/pops/sheep.gif
Populations
• Definition: Group of same species in one
area at one time.
• Ecologists need to define geographic
boundaries.
– Walls of an aquarium in which algae grows
– Deer in a particular state
– HIV infection (humans) in one nation or world
Population Growth
• Exponential Growth: population multiplies
by a constant factor at constant time
intervals.
• Space is a limiting factor: a condition that
can restrict a population’s growth
– Lily pads growing across a pond will reach a
point where the surface of water is completely
covered and no more can grow.
http://photos.atkmotors.com/Lily%20Pad%203.jpg
Carrying Capacity
• Definition: the number of organisms in a
population that the environment can
maintain, or “carry,” with no net increase or
decrease.
• Pop’s that approach carrying capacity:
– Birth rate decrease
– Death rate increase
http://el.erdc.usace.army.mil/aqua/apis/biocontrol/image/minmax.gif
Factors Affecting Population
Growth
• Density-dependent factor- more individuals
in a population (more dense), more limited
the population becomes.
– Food/Resources
• Density-independent factors- affect pop. but
not related to pop. density
– weather
Population Growth Cycles
• Some pop.’s rapidly increase and then
rapidly decrease (crash)
• Some cycle:
– predator-prey dynamic
• Lynx & snowshoe hare
http://members.shaw.ca/grizzlyjake/images/lynx%20chasing%20hare.jpg
•
Human Population Growth
• For most of human history, pop. growth is
very small (or not at all)
• 1650 C.E. (common era) – 500 million ppl.
• Improvements in health care, sanitation &
nutrition allow longer life expectancies &
greater survival
Human Populations
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1650-1850AD – 1 billion ppl.
1930AD – 2 billion ppl.
1980AD – 4 billion ppl.
2006 AD – 6,500,000,000 people on Feb.24, 2006
at 7:16pm
• Present http://math.berkeley.edu/~galen/popclk.html
• Oct. 18, 2012 at 4:36pm – 7,000,000,000
• Currently growing 75mill. ppl per year
Species Interact in Biological
Communities
http://www.ucsc.edu/currents/01-02/art/moth.02-06-24.224.jpg
Competition
• Two or more species in one community fight for a
limited resource.
• Ex) African Savannah: many species rely on
grasses which is a limiting resource.
Competitive Exclusion
• When two species compete for a limiting resource,
and one outcompetes the other.
• Ex) 2 types of Paramecium:
– P.aurelia and P. caudatum
– Fed same amt. of food:
• Separate- both thrives
• Together- P.aurelia could consume food faster &
outcompeted (succeeded over) P. caudatum
Niche
• An organism’s role in its habitat
• Includes:
– Food sources
– Time of day it’s most active
– Any factor specific to organism’s life
http://www.tarleton.edu/~range/Cook%20Pictures/Photo%20Slides_4/184%20coral%20bean.jpg
Predation
• Interaction in which one
organism eats another.
– Lion & egret
• Predator adaptations:
– Fast & agile
– Acute senses (exrattlesnakes have heat
sensing organs behind
each eye)
– Some camouflage
– Claws, teeth, fangs &
stingers
Prey Adaptations
• To avoid being eaten:
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Retreat to safe places
Camouflage to hide from predators
Warning Coloration
Poisonous chemicals
Mimicry of other dangerous species
• Hawk moth puffs up, weaves back and forth, and hisses like a snake
(looks like one!)
Symbiotic Relationships
• Close interactions between species in which
one of the species lives in or on the other.
• 3 types
– Parasitism
– Mutualism
– Commensalism
http://www.dep.state.fl.us/parks/OPG/maclaygardens/photos/wallpaper/1024-PL-MAC-Symbiosis-MarkFerrulo.jpg
http://www.uidaho.edu/so-id/entomology/clb%20parasite.jpg
Parasitism
• One organism, the parasite, obtains
its food at the expense of another
organism (host).
– Mosquitoes
– Tapeworms
– Leaches
• Natural selection works on both
parasites & hosts!
– Parasite better at obtaining food, host
better at defending (plants produce
allelochemicals).
http://www.organicnutrition.co.uk/images/parasite-hookworm.gif
Mutualism
• Both organisms benefit
– Human large intestine & bacteria (bacteria feed
on nutrients we consume, but they produce
vitamins for us)
– Lichens
Commensalism
• One organism benefits while the other is
unaffected (not helped or harmed).
– Crab places seaweed on its back to hide
(seaweed unaffected)
– Mites on our eyelashes
– Barnacles on a whale
http://www.visions-of-science.co.uk/photos/Close-up%202nd%20-%20Eyelash%20mites.jpg
Primary Succession
• When a community arises in a lifeless area
that has no soil.
– New islands from erupting volcanoes (Hawaii)
– Clear-cut land
• 1st to arise= pioneer organisms
– Usually photosynthetic, why?
– Lichens- create soil & make it possible for
other organisms to live in the area.
Primary Succession
• Succession of organisms:
– Lichens>mosses>grasses>shrubs>trees
• How did those new organisms get there?
– Carried by animals
– Carried by wind
• From barren ground to a deciduous forest
can take hundreds or thousands of years!!!
• How long does it take to clear that land?
http://www.anselm.edu/homepage/jpitocch/genbios/primsucc6crat52603.jpg
http://www.geo.arizona.edu/Antevs/nats104/00lect20sucn1.gif
http://www.geo.arizona.edu/Antevs/nats104/00lect20sucn2.gif
Energy Flow & Chemical Cycling
http://www.comm.media.state.mn.us/bookstore/shore/html_in/in_img/ecosystem.jpg
3 Types of Organisms
• Producers: photosynthetic, convert light energy from
the sun to chemical energy in organic compounds
– Plants
– Phytoplankton
• Consumers: obtain energy by consuming producers
or other consumers
• Decomposers: break down wastes and dead
organisms
3 Types Consumers
• Herbivore: eats only producers (horse)
• Carnivore: eats only other consumers (lion)
• Omnivore: eats both producers &
consumers (bear)
http://www.alanandsandycarey.com/Wildlife/Bears/Grizzly%20Bears/images/Grizzly%20Bear%20feeding%20on%20Rose%20Hips%20Montana.jpg
Food Chains
• Energy transfer between
trophic levels
• Trophic Levels
– Producers-flowers,
phytoplankton
– Primary consumersgrasshopper, zooplankton
– Secondary consumers-mouse,
herring
– Tertiary consumers-snake,
cod
– Quaternary consumers-hawk,
killer whale
http://cse.cosm.sc.edu/env_sci/Resources/L_Sus_Res/Soil/trophic.jpg
Trophic Levels Explained
• Primary Consumer: consumer feeds directly
on producers
• Secondary Consumer: feeds on primary
consumers
• Tertiary Consumer: feeds on secondary
consumers
http://pubs.usgs.gov/of/1998/of98-805/lessons/chpt7/energy-sm.gif
Decomposers
• At each trophic level, organisms produce
waste and eventually die.
• Scavengers: consume dead organisms
– Rodents, insects, crayfish, catfish, & vultures
• Main decomposers: Bacteria & Fungi
Food Web
• Diagrams that show the feeding patterns of all
food chains in one area
• Arrows shows the transfer of energy
Productivity of Ecosystems
• Biomass: the amount of organic material
produced on earth (billions of kg)
Pyramid of bio mass
• Most biomass is at the BOTTOM of
pyramid
http://fig.cox.miami.edu/Faculty/Dana/energypyramid.jpg
Pyramid of Energy
• The most energy is at the bottom of the food
chain
Ecological Pyramids
• Energy is spent at each step of the food web
• Some energy is transferred from the lower
trophic level to the higher
• Most energy is lost
• Average: 10% of energy is transferred to the
next trophic level
Carbon & Oxygen Cycle
• In atmosphere, carbon is inorganic in the form
of CO2
• Producers use CO2 to make organic compounds
(photosynthesis)
• Organisms break down organic compounds and
release CO2
– Cell respiration for energy or decomposers produce
this when breaking down detritus
Carbon & Oxygen Cycle
• Nonliving processes also contribute to
cycle:
– Burning fossil fuels (C in organic compounds)
– Burning wood (human activity or forest fires)
– Volcanic eruptions
http://upload.wikimedia.org/wikipedia/en/5/55/Carbon_cycle-cute_diagram.jpeg
Carbon Cycle Impacts
• Industrialized nations: release carbon in
atmosphere by burning fossil fuels
• Deforestation: clearing of forests for
– Agriculture
– Lumber
– Etc
• Problem: release CO2 into atmosphere,
remove plants that absorb CO2
Carbon Cycle Impacts
• Human contribution to carbon cycle:
– 80% of carbon in atmosphere: burning fossil
fuels
– 20%: burning after deforestation
• Problem: CO2 allows sunlight to enter
atmosphere, but does not let heat escape
after reflecting & radiating off earth’s
surface
Greenhouse Effect
• CO2 acts like the glass of greenhouses:
– Sunlight passes through
– Heat cannot escape
– Earth’s average temperature is rising
• Global Warming
– Overall rise of Earth’s temperature
Global Warming
• A few degrees change:
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Melting of glaciers
Sea levels rise
Change in precipitation patterns
Biome boundaries shift
http://www.environment.sa.gov.au/sustainability/images/greenhouse_effect.jpg
Nitrogen Cycle
• 80% Earth’s gas is N2(gas)
• Nitrogen Used to make AMINO ACIDS
which make…
• PROTEINS!
• Nitrogen Fixation: convert N2 gas to
ammonia (NH3)
– Nitrogen fixing bacteria: live in nodules of
peas, beans, alfalfa & clover (in soil)
http://www.windows.ucar.edu/earth/climate/images/nitrogencycle.jpg
Nitrogen Cycle Impacts
• Adding large amounts of nitrogen compounds into
the water and soil
– Fertilizers
• Fertilizers added to crops can run off into streams
& ponds
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Allows rapid growth of algae (algae blooms)
Algae die, bacteria decompose & use up oxygen
Low oxygen=can’t support other organisms (fish)
a.k.a. - EUTROPHICATION
http://www.bbc.co.uk/schools/gcsebitesize/img/bieutrophication.jpg
Nitrogen Cycle Impact
• Smokestacks & car exhaust contain nitrogen
and sulfur compounds
– Combine with water forming nitric acid and
sulfuric acid that precipitates back to Earth’s
surface: acid rain
– Clean Air Act
http://www.dec.state.ny.us/website/dar/ood/acidrain.gif
Water Cycle
• Nonliving processes play a major role
• Sun energy evaporates water from land and
water surfaces
– Add gaseous water vapor to atmosphere
– As cools, water vapor condenses: precipitation
(rain, snow, hail or sleet)
– Plants absorb fresh water from soil
– Consumers eat and drink water
Water Cycle
• Large amounts of water leaves plants via
transpiration.
• What is transpiration???
– Evaporation of water from plant leaves (out through
stomata)
– 200L of water can leave a maple tree on a hot day
• Water not obtained by organisms, flows into
streams, rivers, oceans and the cycle continues.
http://www.anselm.edu/homepage/jpitocch/genbios/54-16-WaterCycle-L.gif
Water Cycle
• Deforestation: reduces transpiration
• Use of water from aquifers and rivers: can
be faster than what the water cycle takes to
replace it
http://www.geocities.com/cgwharton2004/deforestation.jpg
Pollution
• Addition of substances to environments that
result in a negative effect
Biological Magnification
• Process by which pollutants become more
concentrated in higher trophic levels of a food
web
• DDT-1971: pesticide that stores in fats.
– Caused eggs of pelicans, ospreys, and eagles to be
easily broken
– Population declines
– Surviving offspring received DDT also, why?
http://www.glerl.noaa.gov/res/PandP/1996-97/zebra-fw-f1.gif
Damage to the Ozone Shield
• Ozone (O3) layer: 17-25 km above Earth’s
surface and absorbs ultraviolet radiation
• UV light can cause mutations in organisms
• What are mutations?
• Ozone layer has been recorded to be
thinning since the 1970s
• CFCs (chlorofluorocarbons): in aerosol
cans, refrigeration units, etc
http://www.gsfc.nasa.gov/gsfc/earth/pictures/arctictemps/globe.jpg
Ozone Layer
• CFCs destroy ozone
– Skin cancer
– Cataracts
– Crop damage
• Nearly 200 nations are working to eliminate
ozone-destroying chemicals
• http://www.epa.gov/ozone/science/hole/holeani
m.html
Conservation Biology
• Biodiversity: encompasses the variety of life on
earth
• Why does biodiversity matter?
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Species in an ecosystem are interconnected
Depend on the community for food, shelter, etc
One loss of species, can affect all others
25% of medicines from plants in U.S.
Biodiversity Importance
• Rosy Periwinkle in the rain forests of Madagascar:
– Childhood leukemia
– Hodgkin's disease (cancer of lymphatic system)
• U-tree (produces compounds also used for slowing
cancer cells)
Threats to Biodiversity
• 1.5 million species today
• Species disappearing at dramatic rates:
– 11% of 9,040 birds are endangered
– 680 of 20,000 plants species endangered
– 20% of freshwater fishes endangered
Habitat Destruction
• As the human population grows, more land
needed for:
– Agriculture
– Roads
– Communities
• Habitat fragmentation: preventing species
from reaching resources or each other
• Animation:http://bcs.whfreeman.com/thelif
ewire/content/chp54/5402004.html
Introduced Species
• Introduced species (exotic species) often
prey on or compete with native species
• Starlings & Sparrows brought from Europe:
– compete with bluebirds for nesting sites
– Bluebird population decline
http://www.science-house.org/kudzu/kudzu-car.jpg
http://nationalatlas.gov/articles/biology/IMAGES/kudzu.gif
Human Activities
• Introduced Species, aka= exotic species
– Organisms that humans move from the species’ native
locations to new geographic areas, either intentionally
or accidentally.
– Intentional:
• Kudzu Japanese Plant: introduced in the 1930s to control
erosion in irrigation canals. Now grows out of control!
– Accidental:
• Lamprey in the Great Lakes
Overexploitation
• Harvesting or hunting a species to such a small
number that they may not be able to repopulate
– White rhino
• Poachers: illegally hunt animals and sell animal
products for money (elephant tusks and rhino
horns)
Conservation Biology
• Application of biology to counter the loss of
biodiversity
• Focus on “hot spots:” small geographic
areas with high concentration of species
• 1.5% of Earth’s land area
• Biologists, lawmakers, and local
communities try to conserve “hot spots”
Conservation Biology
• Zoned reserves: areas of lands that is
undisturbed by humans
• Buffer zones: surround zoned reserves and
have minimal impact by humans
– Costa Rican Government- world leader in
establishing zoned areas
– Conserved 80% of natural species
Conservation Biology
• Sustainable Development: Developing
natural resources so they can renew
themselves and be available for the future.
– Forest corridor through crop (keep connection
between two parts of an ecosystem)
– Timber harvesting from mature trees only