Transcript COMP 3 PPT

Biology I
Comp 3 Review
Organisms and Their Environments
Introduction to Ecology
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Ecology is the study of organisms and
their interactions with their environment.
The environment includes 2 types of
factors:
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Biotic factors – the living parts of the
environment
 Plants, animals, bacteria, fungi, etc
Abiotic factors – the nonliving parts of the
environment
 Water, oxygen, light, temperature, etc.
Nutrient Cycles
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Some abiotic factors are nutrients that are
needed by plants and animals to survive.
These nutrients are cycled through the
ecosystem.
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Helps maintain homeostasis, or balance,
within the environment.
The 3 main nutrient cycles are:
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Water
Carbon
Nitrogen
Water Cycle
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Evaporation – water changing from a
liquid to a gas
Transpiration – water evaporating from
the leaves of plants
Condensation – water changing from a
gas to a liquid
Precipitation – water returning to the land
in the form of rain, sleet, hail, or snow
Water Cycle
Carbon Cycle
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Photosynthesis and Cellular Respiration
cycle carbon and oxygen through the
environment
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Photosynthesis uses CO2 and produces O2
Respiration uses O2 and produces CO2
Carbon may be returned to the soil
through decomposition
Carbon may also returned to the
atmosphere through volcanic activity and
burning fossil fuels
Carbon Cycle
e
Nitrogen Cycle
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Most Nitrogen is found in the atmosphere,
but organisms can’t use it in that form
Atmospheric Nitrogen is made usable for
living things through Nitrogen Fixation
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Nitrogen-fixing bacteria on the roots of some
plants
Lightning strikes
Denitrification – other bacteria in the soil
can convert “fixed” nitrogen back into
Nitrogen gas (N2)
Nitrogen Cycle
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Assimilation – Plants use Nitrogen in the
soil to form amino acids and other organic
compounds
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Consumers obtain Nitrogen from eating
producers
When plants and consumers die,
decomposers return the Nitrogen to the
soil
Nitrogen Cycle
Levels of Organization
- Ecologists can look at the world in levels
of increasing complexity
Biosphere
Biome
Organism
Population
Community
Ecosystem
Levels of Organization
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Organism –
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Any unicellular or multicellular form that
exhibits all the characteristics of life
An individual
Example: A zebra
Population –
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A group of organisms of the same species
that live together in a certain area
Interbreed and compete for resources
Example: A herd of zebras
Levels of Organization
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Community –
Groups
of organisms of different species
that live together in a certain area
Example: A herd of zebras, a pride of lions,
& a pack of hyenas
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Ecosystem –
All
the living and nonliving things in a certain
area
Communities and the abiotic factors with
which they interact
Example: Zebras, lions, hyenas, rocks, air,
water, etc.
Levels of Organization
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Biome
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a group of ecosystems that have similar
climates and communities
Example: Savanna
Biosphere
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the entire portion of the planet that supports
life
Biomes
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Aquatic
Terrestrial
Tundra
 Taiga
 Tropical Forest
 Savanna
 Desert
 Temperate Grassland
 Temperate Deciduous Forest
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Tundra
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Arctic
Little precipitation: 15-25 cm/year
Average winter temp. -30 degrees C
Summer < 10 degrees C
Long winter; very short summer
Permafrost – almost permanently frozen
snow/ice
Artic fox
Tundra
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Small plants with short roots, a few
DWARF shrubs
Migratory animals or animals with High
tolerance for very harsh conditions
Adaptations: Animals may have white fur
for camouflage. Plants have short roots
because of permafrost.
Caribou
Polar bear
Bearberry
Taiga
(Northern Coniferous Forest)
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Seasonal rainfall: 30-80 cm; some much
more
Winters -50 degrees C in winter
Summer 20 degrees C
Long winter; short summer
Taiga
(Northern Coniferous Forest)
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Spruce
Plants: cone-bearing trees, diverse
shrubs, lichens & mosses
Animals: Migratory animals, large
herbivores & predatory animals
Adaptations: Plants with waxy needles to
help retain water. Animals may hibernate
during coldest months
Moose
Bear
Timber wolves
Tropical Rain Forest
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Seasonal rainfall: 200-400 cm/yr
25-29 degrees C year round
Located along the equator
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Summer year round
Sloth
Orchids
Tropical Forest
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Most diverse species of plants & animals
Plants: Broad leaves, vines, orchids,
bromeliads. Soil lacks nutrients
Animals: Lots of insects and tree dwellers
Adaptations: Many forms of camoflauge,
bright colors, diet heavy on fruits
Toucan
Boa constrictor
Poison Dart Frog
Jaguar
Savanna
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Seasonal rainfall; 50-120 cm/yr, with a
long drought season
Temperature: 20-30 degrees C (warm!)
Distinct wet and dry seasons
Frequent fires during dry season
Aardvark
Savanna
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Plants: Tall grasses, scattered small trees
and shrubs
Animals: Lots of herbivores (grazers), and
carnivores (hunters)
Adaptations: Drought tolerant & fire-resistant
Cheeta
Giraffe
Elephant
Lion
Desert
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Rainfall < 25 cm/yr (arid/dry)
Hot deserts > 50 degrees C
Cold deserts (Antarctica) <-30 degrees C
Extreme changes in temperature
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Ex: Very hot during the day & cold at night
Rattlesnake
Desert
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Plants: Cacti, creosote bushes, succulents
Animals: small nocturnal carnivores, reptiles,
birds & insects
Adaptations: Plants with deep roots and thick
leaves to obtain and hold water. Reptiles
with thick, waterproof skin to hold water.
Many nocturnal animals.
Roadrunner
Kangaroo Rat
Cactus
Fennec Fox
Temperate Grassland
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Dry winters, wet summers: 30-100 cm/yr.;
seasonal drought
Cold winters < -10 degrees C; Hot
summers 30 degrees C
Seasonal drought & periodic fires
Dark rich soil
Blazing stars
Temperate Grassland
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Plants: Lush grasses & wildflowers
Animals: Large herbivores & predators,
burrowing mammals
Adaptations: Drought & fire-resistant
plants.
Pronghorn antelope
Black-tailed
prairie dog
Bison
Coyotes
Temperate Deciduous Forest
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Rainfall: 75-150 cm/yr
Cold Winters & hot summers. 0-35 degrees C
4 distinct seasons
Our biome!
Skunk
Temperate
Deciduous Forest
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Maple
Plants: Deciduous & coniferous trees, shrubs,
mosses, ferns
Animals: variety of mammals, birds, insects
Adaptations: Deciduous trees lose their
leaves in winter to keep from freezing. Some
migratory animals & birds.
Turkey
Squirrel
Deer
Bobcat
Raccoon
Types of Interactions Between
Organisms
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Competition – when resources are scarce,
only some organisms will survive
Food Chains & Webs – diagrams showing
the feeding relationships in an ecosystem
Predator/Prey Relationship – some
animals hunt others for food
Symbiotic Relationship – close interaction
between two or more organisms of
different species
Competition
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When resources are limited, competition
for those resources results.
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Intraspecific competion – between
organisms of the same species
Interspecific competition – between
organisms of different species
Competition
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Limiting Factor – any biotic or abiotic
resource that limits the growth of an
organism or population in a specific
environment
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Availability of water
Availability of food
Availability of habitat
Temperature
Competition
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Density Dependent Limiting Factors –
depend on the number of organisms in a
population
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Food, Water, Predation, Disease
Density Independent Limiting Factors – do
Not depend on the number of organisms in
a population
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Weather, Natural Disasters, Human Activities
Competition
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Habitat – the place where an
organism lives
Niche – the role an organism
plays in its environment
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If two organisms occupy the
same niche they will compete
for resources until one
species is forced out
Niche Partitioning
for Warblers
Food Chains & Webs
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Producers (Autotrophs) – Produce their
own food through Photosynthesis or
Chemosynthesis
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Ex: Plants, algae
Consumers (Heterotrohps) – Must
consume other organisms for food &
energy
Food Chains & Webs
Types of Consumers
Herbivores – Primary consumers
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Eat Plants
Carnivores
– Secondary & higher
consumers
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Eat other animals
Omnivores
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Eat both plants and animals
Food Chains & Webs
Types of Consumers (continued)
Detritivores – Feed on organic
waste (dead plants and animals)
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Ex: Earthworms
– Breakdown dead
plants & animals into simpler
molecules that can be absorbed
Decomposers
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Ex: Bacteria, Fungi
Food Chains & Webs
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The arrows in a food chain/web show the
flow of energy from one organism to the
next
Only 10% of the available energy is
transferred from one trophic level to the
next. The rest is lost as heat.
The Trophic Level of an organism is the
position it holds in a food chain/web/pyramid
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(Primary, Secondary, Tertiary, etc.)
Food Chains & Webs
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Food Chain – a linear representation of
energy transfer between organisms
Food Chains & Webs
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Food Web – a network of interconnected
food chains in an ecosystem
Food Chains & Webs
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Food Pyramids
Pyramid of Energy – Shows the amount of
energy available at each trophic level
Biomass Pyramid – Shows the amount of
biomass at each trophic level
Pyramid of Numbers – Shows the number
of individual organisms at each trophic
level
Food Chains & Webs
Energy Pyramid
Pyramid of Numbers
Biomass Pyramid
Predator/Prey Relationships
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Predator populations can control the size
of Prey populations, and vice versa.
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The Top Predator in an ecosystem has no
natural predators.
Symbiotic Relationships
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Symbiosis – two organisms of different
species living closely together.
There are 3 types of Symbiosis
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Commensalism
Mutualism
Parasitism
Symbiotic Relationships
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Mutualism – Both species benefit
Commensalism – One species benefits
and the other is not affected
Parasitism – One species benefits and
the other is harmed (parasite & host)
Biological Magnification
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Chemicals or toxins may
be introduced into an
ecosystem through
human actions.
As they move up through
a food chain, they have a
more severe affect on
each higher trophic level.
Ex: DDT
Ecological Succession
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Ecological Succession – the predictable and
orderly changes in the composition or
structure of an ecological community over
time.
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Pioneer species – the first species to
populate an area
Climax community – the final community of
organisms in an ecosystem once it becomes
stable
Ecological Succession
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Primary Succession – occurs on surfaces
where no soil exists
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Ex: Volcanic rock surfaces after an eruption
Ecological Succession
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Secondary Succession – occurs on preexisting soil
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Ex: A forrest after being burned or cleared for
construction
Human Impact on Ecosystems
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Biodiversity is the variety of life in an
ecosystem
It may be decreased by human activities
such as:
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Use of pesticides and chemical fertilizers
Deforestation and clearing land for
construction
Introducing non-native species
Exploitation of wildlife