Download Goal Five

Goal Five
The learner will develop an understanding of the ecological relationships among
organisms.
5.01 Investigate and analyze the interrelationships among organisms, populations,
communities, and ecosystems.
o Students should be able to identify and describe symbiotic
relationships
o Mutualism
 Two species interact closely in a way that benefits
both species
 Ants and acacia trees: ants live in the acacia
thorns and eat their leaves, acacias benefit
because ants protect them from predators and
will even destroy other plants that shade the
acacias from the sun
 Honeybees and other insect pollinators have a
mutualistic relationship with many flowers.
o Commensalism
 One organism benefits from the interaction and the
other organism is neither helped nor harmed.
 the clown fish and sea anemone: the clown
fish lives on scraps from the sea anemone’s
meals. When danger threatens, it retreats into
the sea anemone’s waving tentacles. Most
fish are instantly paralyzed by the tentacles,
but the clown fish seems to be immune to the
sea anemone’s touch
 barnacles that live on the skin of whales or sea
turtles barnacles benefit because they are
moved from place to place, increasing their
access to food, the whales or sea turtles are
not affected by the barnacles
o Parasitism
 A parasite lives on or in another organism- its host
 Ticks, fleas, leeches, lice and mites are examples of
parasites that live outside the host, attached to skin or
scales
o Predator/prey
 An interaction in which one species (a predator) feeds
on another species (prey)
 Lynx feeds on snowshoe hares
 Techniques of field ecology
o Field ecology techniques such as sampling and quadrate studies to
determine species diversity and changes over time
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Abiotic and biotic factors
o How they relate to each other and their importance in ecosystems
 Abiotic factors- nonliving parts of the environment (water,
soil, light, temperature, wind, and physical space)
 Biotic factors- living parts of the environment
 Sunlight, water, temperature, and wind are all abiotic factors
that affect climate (climate is the typical weather pattern of
an area over time)
 Climate plays a major role in determining the biosphere
ecosystems are distributed throughout the biosphere
 Biome- a large group of similar ecosystems
 Carrying capacity
o How limiting factors influence carrying capacity (eg. Food
availability, harsh winter)
 A limiting factor is any biotic or abiotic resource in the
environment that limits the size of a population
 Density dependent limiting factors- factors that only become
limiting when the population density (the number of
organisms per unit of space) reaches a certain level
 Density independent limiting factors- environmental factors
that can disrupt or destroy all sorts of populations in the same
way regardless of their density
 Weather, seasonal cycles, natural disasters, and many
human activities
 Population growth graphs (J and S curves)
 j shaped curve- exponential growth
 s shaped curve- reached carrying capacity
 Carrying capacity
 The number of individuals in a population that an
environment can support over a relatively long period
of time
5.02 Analyze the flow of energy and the cycling of matter in the ecosystem
 Relationship of the carbon cycle to photosynthesis and respiration
o Investigate the carbon cycle as it relates to photosynthesis and
respiration
 During photosynthesis producers such as plants and algae
take up carbon dioxide from the air or water around them.
 Producers use carbon dioxide and water to manufacture
glucose, during which oxygen is released
 Producers and consumers use glucose to fuel the process of
cellular respiration
 The reaction releases energy and produces water and carbon
dioxide. The carbon dioxide produced by the reaction is
released into the air or water surrounding the organism
 People have burned large amounts of fossil fuels (an energy
rich compound formed from organic matter by a geological
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process) for energy, releasing huge amounts of carbon
dioxide
o Water cycle
 When water evaporates from oceans, lakes, or other bodies of
water, it enters the atmosphere as a gas- water vapor
 In the atmosphere, the water vapor cools and condenses to
form clouds
 Eventually, clouds release the water they contain, and the
water returns to Earth’s surface as precipitation- rain, snow,
hail, or sleet
 Water from precipitation may collect on the Earth’s surface
to form streams, rivers, and lakes. Most of the water
eventually flows back to the ocean, carrying nutrients and
sediments with it.
 Some water seeps into the ground instead of running off. It
slowly percolates through soil and rock layers and is being
filtered and purified along the way. Eventually, water
moving down through the soil reaches groundwater deep
beneath the surfaces
 Water cycles through living things as well (transpiration,
perspiration, excreation, inhalation)
o Nitrogen cycle
 Nitrogen gas in the air is converted to usuable nitrogen
compounds in a process called nitrogen fixation. Lightning
causes some nitrogen fixation by forming nitrogen oxides
from nitrogen and oxygen in the air. Some nitrogen fixing
bacteria live in soil or water. Others live in nodules on the
roots of plants that belong to the legume family (alfalfa,
peanuts, soybeans, clover, peas)
 Nitrogen fixing bacteria convert nitrogen gas to ammonia
which quickly dissolves in water to produce ammonium ions.
 Certain bacteria convert ammonium ions to nitrates in a two
step process
 Plants use the nitrogen compounds they absorb to make
amino acids, proteins, and other needed substances. Animals
get the nitrogen they need by eating plants or the organisms
that consume plants
 Decomposers break down nitrogen-containing animal wastes
and the remains of dead organisms. The breakdown of these
materials releases ammonia, which dissolves to produce
ammonium ions. Plants take up ammonium ions and nitrates,
and the cycle starts over again
 Denitrification- a group of bacteria converts some of the
ammonia and nitrates into free nitrogen gas
Trophic levels- direction and efficiency of energy transfer
o Analyze food chains, food webs, and energy pyramids
o Trophic levels- each step in the transfer of energy and matter in an
ecological community
o Food chains- models the flow of energy through organisms in a
community
o Direction of energy transfer
o Efficiency of energy transfer
5.03 Assess human population and its impact on local ecosystems and global
environments.
 Historic and potential changes in population
o Factors affecting birth rates and death rates
 In many industrialized countries, declining death rates have a
greater effect on total population growth than increasing birth
rates
 Fertility rates are decreasing
 People are waiting until their thirties to have children
 Today’s families are having fewer children
 When fertility rates are high, populations grow more rapidly
unless the death rate is also high
 Some countries have high death rates among children
because of disease and malnutrition.
o Effects of population size, density, and resource use on the
environment
 Expanding human population is placing huge demands on
natural resources
 As population has grown, humans have developed medical,
agricultural, and other technologies that enable more people
to survive.
o Correlate “J” and “S” curves with food availability and population
o How changes in population is related to other organisms
 Factors associated with those changes
 Climate Change
o Discussion of factors that influence climate change
 Global warming
 Carbon and other emissions as the cause of global
warming
o Increased levels of carbon dioxide may lead to
changes in earth’s climate. These climate
changes are possible because carbon dioxide
in the atmosphere traps heat as does glass in a
greenhouse. If carbon dioxide levels continue
to increase, global warming may occur
o Global warming is an increase in earth’s
average surface temperature
 Possible effects of global warming
o Could cause the oceans to warm and expand,
raising sea levels
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o If polar ice caps melt, sea levels could rise by
many meters, flooding coastal cities and
causing low lying islands to disappear
o Could change rainfall patterns and increase
the amount of violent weather, such as
hurricanes and tornados
 Ways to decrease carbon production
o Reducing the use of fossil fuels
o Preserving forests
Acid rain
Habitat destruction
Natural environmental processes
 Primary succession
o Communities begin to form where none
existed before
o Lichens, which grow on bared rock, and other
pioneer species form a pioneer community
o In time, enough soil accumulates to support
the growth of grasses
o Over time, enough soil accumulates to support
the growth of shallow rooted trees such as
pines
o In the shade of the pines, conditions may favor
the growth of broadleaf trees such as maple
and beech
 Secondary succession
o occurs where a community has been cleared
by a disturbance that did not destroy the soil
 Climax community
o A climax community is one that has achieved
relative stability and species diversity
Resource use
o Investigation of the direct and indirect impact of humans on natural
selection on natural resources (directly-deforestation, indirectlypesticide use and bioaccumulation)
 Bioaccumulation (biological magnification) of some
pesticides resulting in unintended effects
 Biological magnification- buildup of a pollutant in
organisms at higher trophic levels
 Ex. DDT
 Effects of some pesticides on non-target populations
 Resistance to pesticides as an adaptation of some species
 Pros and cons of biocontrols as alternatives to pesticides
 Contribution of Rachel Carson
Sustainable practices/stewardship
o Examples of sustainable practices and stewardship