Below is a narrative describing all of the things we learned in this unit. You should stop after
each section and review the details that are available in your notes and activities.
Avoid memorizing topics, instead do your best to understand them. One great strategy is
explaining the concepts to someone else.
There is a jeopardy review in my outbox, there are several quiz star quizzes that you can now
take for practice.
Scientific Method
Know the steps and be able to identify parts of the scientific method. Identify IV, DV, CV. Be able to label set
ups as control groups and experimental groups.
Decision Making Model
Know the steps and be able to identify parts of the decision making model. If you were given a scenario, you
should be able to identify to complete the decision making model
Spheres Used to Describe The Environment
Biosphere, Atmosphere, Hydrosphere, Lithosphere
You should know what they are be able to provide a few examples for each
Ecosystem Organization
Biosphere Biomes Ecosystems  Communitypopulationorganism
Biome: a large region characterized by a specific type of climate and certain types of plant and animal
communities.
Defined by their plant life: have plants that are specially adapted to the conditions there (ex: short on the tundra
because they cannot obtain water to grow larger; desert plants without leaves to conserve water.)
**You do not have memorize the specifics of the biomes, or know anything about the specific biomes.
Biotic Factors- Living and once living parts of an ecosystem
Abiotic Factors- Nonliving parts of an ecosystem (ex. Air, water, sun etc)
Energy Transfer & Trophic Levels
An organism cannot survive without a constant supply of….ENERGY!
Ultimately all life on earth depends on the sun…
Energy from the sun enters an ecosystem when a plant uses sunlight to make sugar molecules during
photosynthesis. As organisms consume and use energy from carbohydrates, the energy travels from one
organism to another. Organisms use this energy to move, grow and reproduce.
Producer: an organism that makes its own food; also called autotrophs; get their energy directly from the sun.
Consumer: an organism that gets their energy from eating other organisms; also called heterotrophs; get their
energy indirectly from the sun.
Eat only producers=herbivores
Eat only consumers=carnivores
Eat producers and consumers=omnivores
Consumers that get food by breaking down dead organisms= decomposers
Energy Transfer: Each time an organism eats another organism, an energy transfer takes place.
Trophic level: each step through which energy is transferred in a food chain.
Each time energy is transferred from one organism to another, some of the energy is lost as heat and less energy
is available to organisms at the next trophic level. Some energy is lost in cellular respiration. Organisms use
energy to carry out functions of life. 90% of energy at each tropic level is used. Only the remaining 10% can be
part of the organism’s body and stored in its molecules. This stored 10% is all that is available for the next
trophic level when one organism consumes another.Decreased amount of energy at each trophic level affects
ecosystem organization. Since so much energy is lost, there are fewer organisms at the higher levels. This also
limits the number of levels in an ecosystem.
You should know the 9 types of energy and be able to identify examples of each energy type in energy
transformations.
Carbon Cycle
Process by which carbon is recycled between the atmosphere, land, water and organisms.
Short-Term Cycle: Producers absorb atmospheric carbon dioxide in the atmosphere into carbohydrates during
photosynthesis. When consumers eat producers, the consumers obtain carbon from the carbohydrates. As the
consumers break down the food, some of the carbon is released back into the atmosphere as carbon dioxide.
Long-Term Cycle: Carbon may be converted into carbonates (parts of bones and shells). These carbonate
deposits produce limestone rock deposits over millions of years. Limestone is known as one of the largest
carbon sinks on Earth. Some carbohydrates in organisms are converted into fats, oils and other molecules that
store energy. The carbon in these molecules may be released after the organisms die. These molecules may
form deposits of coal, oil or natural gas underground…fossil fuels are made up of carbon compounds from the
bodies of organisms that died millions of years ago.
Human Effect on this Cycle: Atmospheric CO2 is increasing due to increased use of fossil fuels.
Nitrogen Cycle
Makes up 78% of the atmosphere, but most organisms cannot use atmospheric nitrogen. This change from
atmospheric nitrogen to nitrogen compounds that can be used can only be done by nitrogen-fixing bacteria.
Lightening can turn atmospheric nitrogen into usable nitrogen.
Bacteria live in nodules on the roots of legumes (beans, peas, clover). They use sugars from the plants to
produce nitrates. The excess nitrates are released into the soil. Plants get nitrogen from the soil, animals get
nitrogen from plants. Nitrogen is needed for DNA structure.
Phosphorus Cycle
When rocks erode, small amounts of phosphorus enter soil and water. Plants absorb phosphates through their
roots. It is added to soil and water when excreted in waste and when organisms decompose.
Phosphorus is needed to form bones and teeth in mammals; is a component of cells.
Human Effect on Nitrogen & Phosphorus Cycle
Fertilizer use adds excess phosphorus and nitrogen to the environment, which enters waterways through runoff
and cause algae blooms.(eutrophication)
Acid rain adds extra nitrogen to the ecosystem in the form of
nitric acid.
Italicized is not on it, but you will see this concept again later**
Bioaccumulation
As you travel up the food chain toxins and other pollutants
accumulate in the organisms at the top of the food chain.
Biodiversity
This refers to the number of different species present in an
ecosystem. The equation to calculate biodiversity is:
(the number of different species)/(the total number of organism
in the sample).
The higher the biodiversity the more stable the ecosystem is, and the less likely it is for disease to ruin the
ecosystem.
There are 3 types – genetic, species, and ecosystem. Genetic is the number of different genes within one
organism, species is the number of different species within an ecosystem, and ecosystem is the number of
different ecosystems on Earth.
Invasive Species
Invasive species are ones that are not native to the area and begin taking over space or resources. They will take
over the other species niche. Any time 2 species are competing for the same niche, only one will be able to
survive. In class we saw a video on the Asian Carp, and we did the activity with the different “beaks.” There
are many terms for invasive species (non native, exotic). Invasive species are usually carried by human activity,
and when they get to the new ecosystem they tend to take over, lowering biodiversity and taking all of the
resources.
Endangered Species
The endangered species act is the law written by the EPA to ensure biodiversity remains high. The five different
ways a species can be considered endangered is 1) there is a threat to the habitat 2)human interaction is
impacting organism 3)disease and or predators are impacting the organism 4) there is a lack of human
protection 5)any other threats that may impact the organism. There are 3 pieces to the purpose of the
endangered species act, 1) Conserve the ecosystem 2)provide a program to help the species 3)enforcing the law.
There are four prohibited acts in the endangered species act, these include 1)no organisms may be carried
across the high seas 2) you may not import or export any species to foreign commerce 4)Posses any stolen
species. This act is important to preserve threatened and endangered species
Adaptation
An adaptation is something and organism has, that its species acquired over time, to help it survive in its
ecosystem. All organisms have several types of adaptations. We can classify these adaptations into three types
1. Behavioral
2. Physiological
3. Structural
a. Camouflage
b. Mimicry
c. Warning coloration
Humans can sometimes change the ecosystem so quickly that the organisms’ adaptations are useless, and they
do not have enough time to readapt.
Natural Selection
Nature has an impact on the selection of adaptations. There needs to be a variety between organisms, the trait
must be inherited and the trait must help the organism survive and reproduce. If humans impact and area, like
we did during the industrial revolution, then the organisms are either going to die off, or adapt. In the case of
the peppered moth, they adapted by changing color over time. It is important to note that the individual moths
don’t change color, but gradually the offspring get darker overall.
Limiting Factors
A limiting factor is something in the ecosystem that stops an organism for surviving or reproducing. Some
examples include, but are not limited to food requirements, habitat requirements, etc. A species that has
several limiting factors is referred to as a specialist, and a species with very few or no limiting factors is referred
to as a generalist. Generalists have a much easier time surviving than specialist to. Most of the species that are
endangered are specialist.
Species Relationships
Species can interact with each other in two different ways, symbiotically and non symbiotically. The
relationships that fall under symbiosis are mutualism (+/+), commensalism (+/0) and parasitism (+/-). The non
symbiotic relationships are predation (+/x) and competition (-/-). The population graphs for predator prey
follow each other and keep each population constant.
Population
Population is the number of organisms of the same species . Whereas, the population density is the number of
individual organisms in a given area.
When there are no limiting factors, the populations grow exponentially, or in a J-Curve. When there are limiting
factors present the population will either begin to level out at carrying capacity or crash. There is only one
limiting factor applied at a time. The human population, according to some scientists, has over shot its carrying
capacity by a large number so we should soon see the human population (7 billion) decrease. The reproductive
potential plays a role in this, meaning the higher the reproductive rate the more likely we will see exponential
growth.
When considering limiting factors in terms of population, some are density dependent while others are not. The
factors that are density dependant include, but are not limited to space, food, and disease. The limiting factors
that are density independent are natural and manmade disasters.
Graphing is important with population so you should know how to interpret information from graphs and tables.
Estimating populations is another important piece to studying both human and wild animal populations. You
should know the mark and recapture method, as well as the random sampling method.
The human population is growing exponentially, it is unclear what our carrying capacity is, but the thought is we
are going to over soot it very soon.
Types of Survivorship curves, Type I – longer life span with most member making it past midlife (humans), Type
II – consistent drop off of individual and life span does not rely on age, Type III – most members die off prior to
maturity.
Reproductive strategies (r-selection and k-selection)
You should know how to use the mark and recapture as well as the random sampling to estimate a population.