Ecology Exam Review
Biology I, Ms. Tardalo
September 16, 2014
Ecosystems and Change:

Define the following vocabulary terms:
-Ecology: The study of interactions between living organisms and their environments.
-Biotic Factor: Living elements within an ecosystem
-Abiotic Factor: Non-living elements within an ecosystem
-Autotroph: Also called producers, organisms that get their energy from abiotic sources (like the sun)
-Heterotroph: Also called consumers, organisms that get their energy from biotic sources (eating other
organisms)
-Detrivore: Also called decomposers, organisms that get their energy from consuming waste and dead
matter.
-Biodiversity (what can influence biodiversity?): A wide range of organisms living within a defined area.
A lot of things can influence biodiversity, pollution, invasive species, deforestation, disturbances, etc.
Anything that is increasing or decreasing the amount of species present within a system would be
affecting biodiversity.
-Sustainability: Capability of an ecosystem to maintain itself over time.
Energy Flow in Ecosystems:

Define the following vocabulary terms:
Food Web (what do the arrows indicate?): a food web is a series of interconnected food chains,
demonstrating many feeding relationships. The arrows represent energy flow.
Trophic Level: The hierarchical position of an organism in a food chain.
Energy Pyramid: Pyramidal format of expressing energy flow in a food chain.
Producer (and where do I get my energy?): organisms that get their energy from abiotic sources, ie:
plants.
Primary Consumer (and where do I get my energy?): heterotrophs: herbivores, organisms that get
their energy from eating producers
Secondary consumer (and where do I get my energy?): heterotrophs: carnivores, organisms that get
their energy from eating primary consumers
Tertiary consumer (and where do I get my energy?): heterotrophs: carnivores, organisms that get their
energy from eating secondary consumers

Write the 4 trophic levels above into the appropriate place on the energy pyramid below, and
indicate the direction of energy flow with an arrow:
Tertiary consumers
Secondary consumers
Primary consumers
Producers

What can you tell me about the energy that is passed from level to level in an energy pyramid? Why
is this the trend?
The energy that is passed up the energy pyramid decreases from trophic level to trophic level.
Energy is lost due to metabolic processes and heat release, each level receives less from the prior
And then on top of it there is even less to pass on after metabolism.

If I wipe out an organism on a food web, and ask you which organism is most affected by this loss,
what two questions are you going to ask yourself to figure it out?
1) Which organisms depended on the organism that was removed for food?
2) Out of these organisms, which ones have other food sources?

What will you look for if I ask you to identify the primary consumers on a food web? secondary
consumers? tertiary consumers?
Primary consumers will only have a single arrow from a producer/s to them.
Secondary consumers will have a sequence of two arrows, one from the producer to the primary
consumer that eats the producer, and one from the primary consumer to the secondary consumer
that then eats them.
Tertiary consumers will have a sequence of three arrows, one from the producer to the primary
consumer that eats the producer, and one from the primary consumer to the secondary consumer
that eats the primary consumer, and one from the secondary consumer to the tertiary consumer
that then eats them.
Cycling materials in an Ecosystem:

What is always true about the amount of carbon within the entire carbon cycle ?
It is the same- ALWAYS!

What is a carbon reservoir?
A reservoir refers to all the places that carbon passes through during the cycle (ie: the atmosphere,
the ocean, the plants, animals, rocks, soil, decomposers etc.)

Define Greenhouse Effect: The build-up of gases (particularly CO2) in the atmosphere that results in
an excess of heat being held in.

To help you determine the function of an organism within the carbon cycle, you will need to know
photosynthesis and cellular respiration. Please fill out the chart below:
Photosynthesis
Who/What
Reactants
Products
Organelle
(performs this process)
(what does this reaction
require)
(what does this reaction produce)
(that performs process
in a cell)
Autotrophs
(producers)
1) CO2
1) O2
Chloroplast
2) H2O
Cellular Respiration
All living organisms
3) Sunlight
2) C6H12O6
(Glucose)
1) O2
1) CO2
2) C6H12O6
(Glucose)
2) H2O
3) Usable Energy (ATP)
Mitochondria

Using your table, what is the role of autotrophs in the carbon cycle? AN AUTOTROPH IS A
PRODUCER
Autotrophs removes CO2 from the atmosphere and pass carbon in the form of sugar to organisms
that eat them.
-So why does deforestation influence the greenhouse effect?
Trees are no longer removing CO2 from the atmosphere, therefore, CO2 builds up in the
atmosphere, resulting in the greenhouse effect.

Using your table, what is the role of heterotrophs in the carbon cycle?
Heterotrophs return carbon to the atmosphere as CO2.

What is the role of detrivores in the carbon cycle? A DETRIVORE IS A DECOMPOSER!
Detrivores break down waste and dead matter and return CO2 to the atmosphere.

What other human activity increases the CO2 in the atmosphere and why does it build up?
Burning fossil fuels. The cycle cannot compensate for the amount of excess CO2.
The Nitrogen Cycle:

Define the following vocabulary terms:
Nitrogen Fixation (and what/who performs this?): the process by which atmospheric N2, is separated
by lightening or N-fixing bacteria and becomes nitrates ( NO) or ammonia (NH) compounds that can be
absorbed by plants.
Assimilation (what/who performs this?): the process by which usable compounds like NO and NH are
used to contribute Nitrogen atoms to biological molecules like proteins and DNA.
Rhizobium: a particular N-fixing bacteria present in the roots of legume plants.

Please note the following forms of nitrogen
Atmospheric Nitrogen: N2
Nitrogen compounds post fixation(where does it go afterward?): NO or NH, to plants
Nitrogen compounds post assimilation (which two biological macromolecules): protein and DNA
Nitrogen after processed by decomposers (where does it go?): NO, to the atmosphere

Explain how fertilizer use causes algal blooms: Fertilizers contain fixed nitrogen compounds that are
meant to help the plants they are provided for. However, nitrogen compounds that are not
absorbed can wind up in ground water, that eventually winds up in large bodies of water. Algae are
very fond of nitrogen and grow exponentially on the surface of the water. This blocks plants below
from receiving sunlight. Since these plants are unable to perform photosynthesis, the oxygen levels
become too low to sustain life, resulting in a dead zone.

Explain how burning of fossil fuels can lead to acid rain and ozone damage: Burning of fossil fuels
results in increased nitrous oxide ( an NO compound)…
this can combine with water in the atmosphere to form nitric acid, which leads to acid rain
this can also break up O3 molecules by binding Oxygen, resulting in decreased ozone.
Invasive Species:




What is an invasive species? A non-native species that causes harm to the people, economy, or
environment.
How does an invasive species get introduced to a new place? All cases of invasive species are related
to humans, whether directly ( a person intentionally transports a species) or indirectly (a species
stows away on a plane).
What are characteristics that make an invasive species successful? Fast breeding with multiple off
spring, no natural predators.
How do invasive species affect human populations? The environment? The economy?
-humans: allergies, skin irritants, poisonous/toxic, pathogen carrying
-environment: anything that affects other species or the natural habitat
-economy: property damage, tourism decrease, government $ to research solutions
Symbiotic Relationships:

Define the following vocabulary terms and give an example:
Mutualism: when both species are benefiting from a relationship. Bees and Flowers
Commensalism: when one species is benefiting and there is no harm to the other species. Clown Fish
and Anemone
Amensalism: when one species is inhibited (harmed, disabled) and the other species is unaffected
(neither benefits nor is harmed). Sea Lion and Toxic Diatom
Parasitism: when one species is benefiting and the other is harmed. Tick and Human

Why do you think there is speculation that commensalistic relationships may be earlier forms of
mutualism?
It is possible that we don’t yet understand how the organism we think is unaffected by the
relationship is benefiting.
Population Growth Rates

Define the following vocabulary terms:
Carrying Capacity: The maximum amount of an organism an ecosystem can support with the available
resources.
Equilibrium: When the population of a species is maintained around carrying capacity.
Density Dependent Factor: Factors that depend on the population size. How the population is affected
is based on how big the population is. ie: disease
Density Independent Factor: Factors that do not depend on the population size. The factor will affect
the population the same, no matter what the size of the population. ie: natural disaster

Draw the following Graphs and give an example of when you may expect this kind of graph:
Linear Increase: when a population increases by the same amount over intervals of time.
Exponential Growth: when a population increases by large amount over shorter intervals of time.
S-Curve: when a population grows at a linear rate, accelerates to exponential rate, then reaches carrying
capacity
Population Crash: when a population is brought very low by mass death.
Ecological Change and Resilience

Define the following vocabulary terms:
Disturbance: an event that abruptly and significantly alters available resources and/or types or numbers
of species present in an ecosystem.
Ecological Succession: The process by which an ecosystem responds to an event.
Primary Succession: When succession starts with no life or soil after the disturbance.
Secondary Succession: When succession starts with some soil or plant life remaining after the
disturbance.
Resilience: An ecosystem’s ability to return to a stable condition after a disturbance
Resistance: An ecosystem’s ability to avoid changes in the previously existent ecosystem

What factors determine whether or not an ecosystem can bounce back after a disturbance?
How bad was the disturbance? Is there soil? Plant life? Animal life? Are there animals nearby that may
move here? Might an invasive species be able to take over?
Animal Behavior

Describe the benefit of societies within the animal kingdom, both generally and from an
evolutionary stand point.
Societies keep one another protected and fed. This means that they have a greater chance of
surviving and reproducing to pass on their genes.

List the 4 types of learning, and describe Pavlov and Skinner’s experiments under the appropriate
form of learning.
1) Habituation: decreased response, or completely ignore repetitive stimulus. (saves energy!)
2) Classical conditioning: (Pavlov) mental connection between a stimulus and a reward or
punishment. The dog drools when food is present, a bell is rung every time dog is fed,
eventually, when food is not present, dog still drools when hears bell.
3) Operant Conditioning: (Skinner) trial/error, repeated practice of a behavior results in reward or
punishment. Skinner box has button for food, animal learns after accidentally hitting button
that will be fed if intentionally pushes button.
4) Reasoning/Logic: ability to apply previous learning to new situation with no practice (humans
and primates)

Describe what innate means, what elicits innate behaviors?
Innate means inborn or instinctual behaviors, organisms are born knowing how to perform these
behaviors . Innate behaviors are governed by genetics and the environment.

Name the 4 types of communication:
1)Visual
2)Auditory
3)Chemical
4)Tactile

Define the following vocabulary terms:
Caste: hierarchical roles within a society (ie: queen, worker)
Pheromone: chemical communication that dictates the development or behavior within organisms of
the same species.
Ritual: a series of behaviors that are performed exactly the same by every member of a species.
Taxis: an innate movement toward or away from a stimulus.
Estivation: long period of sleep during hot times to avoid conditions where resources are low
Migration: leaving to go to another place and then returning to the point of origin to avoid conditions
when resources are low.
Imprinting: Combined innate and learned behavior- animal knows to follow what they see but do not
know what that thing looks like. Animal fixates on first moving thing seen when born, usually their
mother. Keeps newborn safe and provides food. Irreversible process.