Transcript Ecology

Ecology
What is Ecology?
• The scientific study of interactions among
organisms and between organisms and
their environment
Levels of Organization
• Individual organisms
• Populations: groups of individuals that belong to
the same species (Species- group of organisms
so similar to one another that they can breed
and produce fertile offspring) and live in the
same area
• Community: Assemblages of different
populations that live together in a defined area
Levels of Organization (continued)
• Ecosystem: Collection of all the organisms that
live in a particular place, together with nonliving,
or physical, environment
• Biome: A group of ecosystems that have the
same climate and similar dominant communities
• Biosphere: Combined portions of the planet in
which all of life exists, including land, water, and
air, or atmosphere (8km above surface and
11km below in the oceans)
Energy Flow
Energy Flows
• Energy flows through an ecosystem in one
direction
– Sun
Autotrophs
Heterotrophs
Sunlight
• The main energy source for life on Earth
Autotroph
• Plants, some algae, and certain bacteria
• Capture energy from sunlight or chemicals
and use that energy to produce food
• Also called producers because they make
their own food
Photosynthesis
• Autotrophs use light energy to convert
carbon dioxide and water into oxygen and
energy-rich carbohydrates
Chemosynthesis
• Autotrophs (such as bacteria) that use
chemical energy instead of sunlight to
make carbohydrates
Heterotroph
• Animals, fungi, and
many bacteria
• They must rely on
other organisms for
their energy & food
supply
• Also called
consumers
Types of Heterotrophs
• Herbivores
– Eat only plants
– Cows, deer, & caterpillar
• Carnivores
– Eat only animals
– Snakes, dogs, & owls
• Omnivores
– Eat both plants & animals
– Humans, bears, & crows
Types of Heterotrophs
• Detritivores
– Eat plant & animal remains & other dead
matter known as detritus
– mites, earthworms, & snails
• Decomposers
– Break down organic matter
– Bacteria and fungi
Classification
• Pick up a stack of pictures
• Sort them into 2 piles
– Autotrophs
– Heterotrophs
• Sort the heterotrophs into 4 piles
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Herbivores
Carnivores
Omnivores
Decomposers
• Make a list of what organisms are in each pile
Food Chains
• A series of steps in which organisms
transfer energy by eating and being eaten
• Must be a straight line
• Grass
Producer
Antelope
Coyote
Primary
Consumer
Secondary
Consumer
Food Chain
• Draw a food chain of which you are a
member
Food Web
• Network of complex feeding relationships
among various organisms
• Links all food chains in an ecosystem
together
Trophic Level
• 1st trophic level –
Producers
• 2nd trophic level –
Primary Consumer
• 3rd trophic level –
Secondary Consumer
• 4th trophic level – Tertiary
Consumer
• 5th trophic level –
Quaternary Consumer
Ecological Pyramid
• A diagram that shows the relative amounts
of energy or matter contained within each
trophic level in a food web or food chain
– Energy Pyramid
– Biomass Pyramid
– Pyramid of Numbers
Energy Pyramid
• Only about 10% of the energy in each
trophic level is transferred to the next
higher level
• 90% of the energy is lost as heat
1%-2nd level Consumer
10%- 1st level Consumer
100% -Producers
Heat
Biomass Pyramid
• Amount of living matter at each level in
grams
• The greatest biomass is usually at the
base of the pyramid
Human 50 grams
Chicken 500 grams
Grain 5000 grams
Pyramid of Numbers
• Shows the relative number of individual
organisms at each trophic level
3rd level consumers
2nd level consumers
1st level consumers
Producers
Pyramid of Numbers
What Shapes An Ecosystem?
What shapes an ecosystem?
• Abiotic Factors
– Physical or nonliving factors
– Temperature, precipitation, humidity, soil type,
sunlight
• Biotic Factors
– All living things with which an organism might interact
– Birds, trees, mushrooms, algae, herons
Niche
• Full range of physical and
biological conditions in which an
organism lives and the way in
which the organism uses these
conditions
• Includes type of food and how it
obtains food, physical
conditions it needs, how and
when it reproduces, and more
Predation
• An interaction in which one organism
captures and feeds on another organism
• Predator
– Organism that does the killing and eating
• Prey
– The food
Predator and Prey
Symbiosis
• Any relationship in which two species live
closely together
• Three types
– Mutualism
– Commensalism
– Parasitism
Mutualism
• Both species benefit
from the relationship
• +,+
• Example-Flowers and
insects
Commensalism
• One member benefits
and the other is
neither helped nor
harmed
• +,0
• Example- Barnacles
and whales
Parasitism
• One organism lives
on or inside another
organism and harms
it
• +,• Example- Tapeworms
and mammals or fleas
and dogs
Parasitism
Biomes
Biomes
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Tropical Rain Forest
Tropical Dry Forest
Tropical Savanna
Desert
Temperate Grassland
Northwestern Coniferous Forest
Boreal Forest
Tundra
Biomes
• Species vary in their adaptations to
different conditions
• Adaptations-Inherited characteristics that
increases an organisms ability to survive
and reproduce
Adaptations of Plants and
Animals
• Cactus-Leaves are only spines to reduce
water loss and stem stores water
• Desert rats-kidneys conserve water and
extract water from food
• Rain forest plants have long thin leaves
that shed excess water
Population Growth
Population Growth
• Factors that affect population size
– # of births
– # of deaths
– # of individuals that enter/leave the population
Exponential Growth
• Abundant space and food and protection
from predators and disease
• Ideal conditions with unlimited resources
• Individuals produce at a constant rate
Growth of Elephant Population
Exponential Growth
Logistic Growth
• Resources become less available and the
growth slows or stops after a period of
exponential growth
Carrying capacity
• Number of individuals of a species that a
given environment can support
Carrying capacity
Limiting Factor
• A factor that causes population growth to
decrease
• May be density-dependent or densityindependent
Density Dependent Factors
• Limiting factor that depends on population
size
– Competition-In crowded populations,
organisms compete for food, water, space,
sunlight, and other essentials
– Predation
– Parasitism
– Disease
Density-Independent Factors
• Affect all populations in similar ways
regardless of the population size
– Unusual weather
– Natural disasters such as droughts
– Human disturbances such as damming rivers
Biological Magnification
• Concentration of a harmful substance
increases in organisms at higher trophic
levels in a food chain or food web
• Top level carnivores are at highest risk
Biological Magnification
Fish-eating Birds
Large Fish
Small Fish
Zooplankton
Producers
Water
Magnification of
DDT
Concentration
Cycles of Matter
Biogeochemical Cycles
• Cycles that connect biological, geological,
and chemical aspects of the biosphere
Water Cycle
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Evaporation-liquid to gas
Transpiration-evaporation from leaves
Condensation-water vapor into clouds
Precipitation-Rains, sleets, or hails
Runoff-water from stream to ocean
Groundwater seepage
Roots uptake water
Water Cycle
Carbon Cycle
• Released to atmosphere
– Volcanic activity and erosion
– Respiration
– Burning of fossil fuels and vegetation
– Decomposition of organic matter
Carbon Cycle
• Absorbed
– Plants take in carbon dioxide
– Plants eaten by heterotrophs
– In ocean in calcium carbonate
– Burial and decomposition of dead organisms
& conversion to fossil fuels
Nitrogen Cycle
• Nitrogen fixation-bacteria in soil and roots
of plants called legumes convert nitrogen
into ammonia
• Other bacteria convert ammonia into
nitrates & nitrogen
• Producers (plants) use nitrates and
nitrogen to make proteins
Nitrogen cycle (continued)
• Consumers eat producers and reuse the
nitrogen to make their own proteins
• When the consumers die, decomposers
return nitrogen to the soil as ammonia
• Ammonia is taken up by producers or
converted to nitrogen gas by bacteria
(called denitrification)
Phosphorus Cycle
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Important in DNA and RNA
Not in atmosphere but on land
Rocks wear down and released
Some reaches ocean and used by marine
organisms
• Some stays on land and plants absorb and
pass on through food web