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Ecology
AP Biology
Ecology Background Terms
• ____________-a group of individuals of the same
species living in the same area
• ____________- a group of populations in the same
area
• ____________- the interrelationships between the
organisms in the community and their physical
environment
• ____________- all of the ecosystems on earth
• ____________- a place where an organism lives
• ____________- describes all the biotic (living) and
abiotic (nonliving) resources used by an organism
in the environment- their place in the ecosystem is
their niche
Population Ecology
• The study of the growth, abundance and distribution of
populations. Described by:
• ____________ of a population- symbolically represented
by N- is the total number of individuals in the population
• ____________- the total number of individuals per unit of
space
• ____________- how individuals in the popuilation are
distributed. They may be clumped (humans in cities),
uniform (trees in an orchard), or random (trees in some
forests)
• ____________ structure- the abundance of individuals of
different ages
• ____________ curves- describe the mortality (death) of
individuals during different parts of their lifetimes
Age Structure Pyramids
Survivorship Curves
• Type I curves- species in which most individuals
survive to middle age, after that mortality is high. EX-
____________
• Type II curves- species in which the length of
survivorship is random- the likelihood of death is the
same at any age. EX- ____________
• Type III curves- species in which most individuals die
young. EX- _____
Terms Describing Population Growth
• ________________maximum growth rate of
the population under ideal conditions
• ________________maximum size of the
population in a particular habitat
• _________________anything that limits the
size of a population. They can be:
– Density ____________- limit the size of a
population based on how close the organisms are
to each other. EX- diseases
– Density ____________- limit the size of a
population regardless of how close they live to
each other EX- natural disasters
Population Growth
• ____________Grow
th- occurs when a the
reproductive rate is
greater than zero. On a
graph, exponential
growth forms a J-shaped
curve.
• ____________Grow
th- occurs when limiting
factors restrict the size of
the population to the
carrying capacity of the
habitat. On a graph, it
forms an S-shaped curve
Reproductive Strategies
• There are two types:
1. ____________species- exhibit rapid exponential
growth. This type of reproductive strategy is
characterized by opportunistic species- such as
grasses and many insects- that quickly invade a
habitat, quickly reproduce, and then die. They produce
many offspring that are small, mature quickly and
require little (if any) parental care.
2. ____________species- population size remains
relatively constant at the carrying capacity. Species of
this type, such as humans, produce a small number of
relatively large offspring that require extensive
parental care.
Predator Prey Relationships
Human Population Growth
• A thousand years ago the human population began
undergoing exponential population growth. This was
made possible by:
– Increases in ____________supply due to domesticating
animals and plants, as well as technological advances in
farming (such as enriching soil with nitrogen)
– Reduction in ____________- advances in medicine, such
as antibiotics, vaccines, and proper hygiene
– Water ____________and sewage systems- reduce health
hazards
– Expansion of ____________- better housing, warmer
clothing, access to energy for heating/cooling/cooking,
transportation
Human Population Growth
Community Ecology
• Is concerned with the interaction of populations. One
form of interaction is interspecific competition
(between two different species). The following are
ways this competition can be resolved:
– ________________________Principle- when two species
compete for exactly the same resource (or occupy the
same niche) one species will eventually outcompete the
other. No two species can occupy the same niche
– ________________________-some species coexist in
spite of apparent competition for the same resources. This
is because they actually pursue slightly different niches.
EX- five species of birds coexist in the same type of tree by
feeding on insects in different regions of the tree.
Resource Partitioning
Niches
• ____________Niche- the niche an organism occupies in
the absence of competing species
• ____________niche- the actual niche the organism
occupies when competition is present
Predation
• Can be categorized as follows:
– A true ____________kills and eats another animal
– A ____________spends most or all of its life living on
another organism (the host)
– A ____________is an insect that lays its eggs on a host
and the larvae each the ost when they hatch
– A ____________is an animal that eats plants. Some may
consume the entire plant.
Symbiotic Relationships
• ____________- when two species live together in close
contact. There are different types:
• ____________- both species benefit. EX- acacia trees provide
food and shelter for ants. The ants kills any insects, fungus, or
vegetation on or near the tree
• ____________- one species benefits, the other is unaffected
EX- birds nest in trees
• ____________- one species benefits, the other is harmed EXtapeworms
Coevolution
• In the contest between predator and prey, some have evolved
unique heritable characterists:
– ____________compounds- toxic compounds made by
plants that discourage herbivores. EX- tobacco plants
– ____________(cryptic coloration)- allows organisms to
blend in EX- leaf and stick bugs
Coevolution
• ____________coloration- is a conspicuous pattern or coloration
that warns predators that they sting, bite, or taste bad
• ____________- When two species resemble one another in
appearance. There are two types:
– ____________mimicry- where both animals are dangerous.
They share the same appearance- this is thought to teach
predators through power in numbers. EX- wasps and bees
– ____________mimicry- one species is harmful, but the other is
harmless and gains protection by pretending its dangerous. EX.
Some species of flies have yellow and black markings to
resemble bees.
Succession
• ____________- change in species composition in a
community over time. ____________succession occurs
when a new habitat forms- such as with a volcanic island.
____________succession occurs after a natural disaster.
• Some of the changes that occur include:
– ____________ species are the first species to start growing.
They tolerate intense conditions.
– Substrate texture may change from solid rock to sand or to
fertile soil as rock erodes and plant and animal decomposition
occurs
– Soil pH may decrease due to the decomposition of materials
such as leaves
– Soil ability to retain water may change.
– Light availability may change
– Crowding may push out certain species
– The final community structure that forms is called the
____________community
Energy Flow in Ecosystems
• ____________Level- a level in a food chain
• ________________________- autotrophs that convert light
energy into chemical energy. Include plants, photosynthetic
protists, and cyanobacteria
• ________________________- herbivores- eat primary
producers
• ________________________- or primary carnivores- eat the
primary consumers
• ________________________- eat secondary consumers
• ____________- consumers that obtain their energy by eating
dead animals and plants (detritus). The smallest detritovores
are called ____________and include bacteria and fungus.
Others include earthworms and vultures.
Energy Flow in Ecosystems
• ____________-a
linear flow of who
eats whom
• ____________many food chains put
together
• As you go up a food
chain- only about
____of the energy is
passed along- the
other 90% is used by
the organism for
metabolic activities.
• ____________levela level in a food
chain
Biogeochemical Cycle
• Describe the flow of essential elements from the
environment to living things and then back to the
environment.
• We will look at the major storage locations for each
element (____________), the processes through
which each element incorporates into terrestrial
plants and animals (____________) and the
processes through which it’s released back into the
environment.
Water Cycle
• Reservoirs- oceans, air (as water vapor), groundwater and glaciers.
• ___________, wind and _______________move water from oceans to
land.
• Plants absorb water from the soil.
• Animals drink water or eat other organism and use their water.
• Water is release from plants through ____________and from animals
when they sweat. Released from both when they die and decompose.
Carbon Cycle
•
•
•
•
•
•
Carbon is required for the building of all ______________ molecules
Reservoirs- _____________ (as CO2), fossil fuels (coal, oil)
Plants use CO2 for __________________
Animals ___________ plants and obtain their carbon in organic molecules
Animals breathe out the carbon in CO2
CO2 is released when anything is _____________
• Nitrogen is required for
making all ________ acids
and __________ acids
• Reservoirs________________ (N2)
and soil
• Plants absorb nitrogen as
either NO3 or NH4
• Animals obtain nitrogen by
eating plants or other
animals
• Animals excrete nitrogen is
in their ___________
• Nitrogen is put into the soil
from the atmosphere
(nitrifiation, nitrogen fixation)
and removed from the soil to
the atmosphere
(denitrification)by
______________
Nitrogen Cycle
Phosphorus Cycle
•
•
•
•
•
Phosphorus is required for the manufacture of _____ and all nucleic acids.
Reservoirs- ___________
Plants absorb phosphorus from soils
Animals obtain phosphorus from eating plants and other animals
Plants and animals release phosphorus when they die and decompose.
• Animals excrete phosphorus is in their urine
Biomes
• ______________- regions that have common environmental
characteristics
• ___________ rain forests- high temperatures and heavy
rainfall. Tall trees, but little growth on the forest floor due to a
lack of light.
• ______________- grasslands with scattered trees. Tropical
with high temperatures, but less water than rain forests.
• Temperate _______________- less water and lower
temperatures than savannas.
• Temperate _____________ forests- warm summers and cold
winters where trees drop their leaves.
• _______________- hot and dry. Animals and plants have
adaptations to deal with harsh conditions.
Biomes
• _____________- coniferous forests. Cold winters
and precipitation in the form of snow.
• __________- winters so cold the ground freezes.
During the summer, the upper topsoil thaws, but the
deeper soil (called permafrost) stays frozen.
• __________ water biomes- ponds, lakes, streams,
rivers
• ____________ biomes- estuaries (where rivers meet
oceans), and the ocean
Biomes
Human Impact on Biosphere
• Human activity damages the
environment:
– _______________ effectthe burning of fossil fuels
increases carbon dioxide
in the atmosphere. The
increased carbon dioxide
causes more heat to be
trapped near the earth’s
atmosphere. As a result,
global temperatures are
rising. This could raise
sea levels by melting
more ice.
Human Impacts
• _________ depletion- the
ozone layer form in the upper
atmosphere when UV
radiation make O2 form O3
molecules (ozone). The
ozone absorbs UV radiation
and prevents it from reaching
earth where it can damage
the DNA of plants and
animals. Pollutants such as
CFCs (chlorofluorocarbons)
have been used as
refrigerants and propellents
and remove O3 from the
atmosphere. This has left
major areas of thinning
called ozone holes.
Human Impacts
• ________ rain- burning fossil fuels and other industrial
pollutants contain sulfur dioxide and nitrogen dioxide. When
they react with water they produce sulfuric acid and nitric
acid. They return to the soil in rain or snow and can kill
plants and animals.
• _________________- Overgrazing of grasslands that
border deserts transform grasslands into desert.
• _________________- Clear cutting of forests causes
erosion, flooding, and changes in weather patterns. The
slash and burn method of clearing tropical rainforests for
agriculture increases atmospheric carbon dioxide,
contributing to the greenhouse effect. Because most of the
nutrients in rainforests are stored in the plants, the soil is
poor and can only support agriculture for a few years.
Human Impacts
• ______________
_________________- some
pollutants, such as the
pesticide DDT or mercury, are
not broken down in the
environment and accumulate in
the fatty tissues of organisms.
As you go up in a food chain
the concentration of these
pollutants is higher. The
biological magnification of DDT
led to several species of birds,
including the bald eagle, nearly
going extinct.
Human Impacts
• _________ Blooms- can be caused by fertilizer or sewage running off into
a lake. When the algae eventually die, bacteria break them down, and the
bacterial growth depletes oxygen in the lake. The result is oxygen
starvation for many animals, including fish and invertebrates. This is called
____________________.
• Reduction in __________ ______________- as a result of human
activities- including habitat destruction, and hunting/poaching