Download Midterm 2013 Review

March 18th 2013
ECOLOGY REVIEW 1
Ecological Organization
Biosphere
Biome
Ecosystem
Population
Organism/Individual
Community
Ecological Organization Terms
 A. Community is a group
of different populations
that live in the same area
 B. Population is a group
of the same species that
lives in the same area
 C. Individual is one
organism
 D. Biosphere is the part
of the Earth in which life
exists
 E. Ecosystem all the
organisms that live in a
particular place,
together with their
nonliving environment
 F. Biome is a group of
ecosystems that have
the same climate and
communities
Energy Flow
In an ecosystem, we have two
categories of organisms:
 Producers / Autotrophs
 make their own food either through photosynthesis or chemosynthesis
 create chemical energy for all consumers
 examples: plants, bacteria, algae
 Consumers/ Heterotrophs
 rely on other organisms for their energy
 fall into one of the following categories
 Herbivore : eats only plants
 Carnivore : eats only meat
 Omnivore : eats both plants and meat
 Scavenger: eats dead animals
 Decomposer : breaks down dead material
 examples: all animals, fungi and some bacteria

Energy Flow
A food chain shows the flow of energy through an
ecosystem.
 The arrow in a food chain shows the transfer of ENERGY from
organism to organism.
 The organisms in food chains are assigned to trophic levels:





Producer
Primary Consumer
Secondary Consumer
Tertiary Consumer
Quaternary Consumer
 Each trophic level receives only 10%of the energy from the
level before – the other 90% is used by that organism for its
own metabolism.
Energy Flow
Food chains in an ecosystem become interconnected into a
complex food web.
 What are the primary consumers?

Are there any tertiary consumers?

Can any organism in this food web be
classified in more than one trophic level?

If the grasshopper were removed from
this food web, which organisms would be
affected? How?

A population of bass was introduced into
this ecosystem. They primarily feed on
zooplankton and detritus. How would the
balance of the ecosystem be changed?
Answers to Food Web
 What are the primary consumers?
 Zooplankton, Ribbed Mussels, Grasshopper
 Are there any tertiary consumers?
 yes, the hawk
 Can any organism in this food web be classified in more than one
trophic level?
 no
 If the grasshopper were removed from this food web, which organisms
would be affected? How?
 The shrew’s population would decrease because they’d have less
food
 The marsh grass would increase because the grasshopper wouldn’t
be eating them
 A population of bass was introduced into this ecosystem. They
primarily feed on zooplankton and detritus. How would the balance of
the ecosystem be changed?
 Feeding on a producer and a primary consumer so would be both a
primary and secondary consumer
Ecological Pyramids
 There are three types of ecological pyramids:
 a. Energy Pyramids – show amount of energy
available at each trophic level
 Biomass Pyramids – show mass of living
organisms at each trophic level
 Number Pyramids – show how many living
organisms at each trophic level.
 All three pyramids resemble each other when
shown graphically.
Biogeochemical Cycles
There are three main cycles of nutrients in an ecosystem:
water cycle, carbon cycle and nitrogen cycle.
 Nitrogen Fixation is when bacteria in the soil change the
atmospheric nitrogen into nitrates and ammonia
 Denitrification is when bacteria in the soil change nitrates
and ammonia back into atmospheric nitrogen
Carbon Cycle
 Carbon can be cycled by: Respiration,
Photosynthesis, Erosion, Volcanic Activity,
and Decomposition
Water Cycle
PRECIPITATION
CONDENSATION
EVAPORATION
RUN OFF
March 19th 2013
ECOLOGY REVIEW 2
Ecological Relationships
 An organism’s habitat is the physical location in which it
lives.
 An organism’s niche is the way that it interacts and
participates in the ecosystem.
 A niche includes:
 Reproductive patterns
 Feeding relationships
 Habitat
 Competition
 The competitive exclusion principle says that no two
organisms can occupy the same niche in the same
habitat because the level of competition would eliminate
one.
Ecological Relationships
 Symbiosis – a close living relationship
between two organisms or two species.
 Mutualism – both organisms benefit + / +
 Parasitism – one benefits and one is harmed + /  Commensalism – one benefits and one is
unaffected + / 0
Succession
 Succession is a change from one ecosystem to a more
stable ecosystem over time.
 Primary succession occurs on land where soil previously
existed.
 Solid rock from volcanic eruption or glaciers receding
 Pioneer species come in to form soil from the rock. Examples are
lichens and mosses.
 After soil is established, grass, shrubs and trees follow from
smallest to largest.
 Secondary succession occurs after an ecosystem is
destroyed by natural disasters or human activities.
 Soil is already formed and remains after ecosystem is destroyed.
 Succession begins with grasses and then shrubs and trees quicky
follow.
Populations
 There are three types
of population growth:
1. Linear – never occurs
in real populations
2. Exponential – will
occur in all
populations as long
as there is an
unlimited supply of
resources.
Populations
3. Logistic – once a population
reaches carrying capacity,
growth will slow and the
population will stabilize.
 Carrying capacity is the
maximum number of
organisms of a species that an
ecosystem can support.
 Populations will fluctuate
around the carrying capacity,
occasionally above it and
occasionally below it – this
happens with availability of
resources
Populations
 Limiting Factors – anything that limits an
organism’s ability to survive.
1. Density-dependent – the effect of the factor
depends on the size of the population.
 predation, parasitism, disease
2. Density-independent– will effect all
populations the same regardless of size.
 Natural disasters & human activities
Populations
 Human population is growing exponentially.
 Technology has allowed us to get past the carrying
capacity.
 Medical advances
 Agricultural practices
 Nature keeps population in check with disease and
disasters.
 Demography – the study of the human population
 Immigration – organisms moving into a population
 Emigration – organisms moving out of a population
 Age-structure – the number of
organisms in a population at each
age group
Environmental Problems
 Global Warming
 An excess of greenhouse gasses is trapping
rays from the sun here on earth, which is
raising global temperatures.
 Greenhouse gases = carbon dioxide (CO2),
methane, and nitrous oxide.
 Effects of global warming –




More severe weather patterns
Rising sea level
Change in crop ranges
Increased respiratory diseases
Environmental Problems
 Biodiversity & Habitat Destruction
 Biodiversity is the variety of organisms in an
ecosystem.
 The more we disturb habitats, the more we decrease
biodiversity.
 Organisms can be classified as threatened,
endangered, or extinct when biodiversity is
threatened.
 Pesticide Use
 DDT – a banned pesticide that caused many problems
in birds of prey through biological magnification.
 Biological magnification – an increase in toxins as you
move up the trophic levels in a food chain.
March 20th 2013
BIOCHEMISTRY REVIEW
pH
1. The amount of Hydrogen ions in solution is
the pH of a substance.
2. A low number on the pH scale means that an
acid is present. 0-6 on the scale is acidic
Examples:
lemons
Stomach acid
Vinegar
Soft drinks
pH
3. pH of 7 means the substance is Neutral.
Examples:
Water
4. A high number on the pH scale means a Base is
present. 8-14 on the scale is basic
Examples:
Bleach
Ammonia
Soap
Tums or Rolaids
5. Buffers prevent major changes in pH these help
maintain Homeostasis in the body.
Biomolecules
1. The four Biomolecules are:
 Carbohydrates
 Lipids
 Nucleic Acids
 Proteins
2. They all contain carbon, oxygen and
hydrogen
Carbohydrates
1. Simple Carbohydrates are sugars they have ose endings like glycogen and glucose.
2. Sugar can be tested by using Benedicts
solution. The solution turns from Blue to
Orange.
3. Complex carbohydrates are long chains of
sugars that store energy for cells they are
commonly called starches.
 4. Starches can be tested by using Iodine it
turns from brown to black/purple.
Lipids:
1. Lipids are more commonly known as Fats or
Waxes and are hydrophobic or dislike water.
2. They make up the membranes of cells which
are composed of a lipid bilayer.
3. They are used to store energy in the body in
long chains these chains are made out of
Fatty acid and Glycerol molecule.
4. Lipids are found by using a Brown Paper bag
test.
Nucleic Acids:
1. Nucleic acids include DNA and RNA.
2. Nucleic acids store and transmit genetic
materials.
Proteins:
1. Proteins are made up of chains of Amino
acids.
2. Proteins are used for growth and repair of
cells. They also are used for commutation
between cells.
Enzymes:
1. Enzymes are a class of Proteins that assist in
chemical reactions by speeding up the
reaction. They act as Biological Catalysts.
2. Enzymes speed up reactions by lowering the
activation energy needed to get the reaction
started.
Enzymes:
3. Enzymes can be denatured or made so they
no longer work correctly by Heating, or
Changes in PH.
4. Enzymes work like a Lock and a Key they are
specific to the reaction.
5. Label the structure below: Enzyme,
Substrate, Active Site.