Test 1 Flashcards
what is ecology?
the scientific study of the abundance and distribution of organisms in relation to other organisms and environmental conditions.
What is another definition of ecology?
The scientific study of the interactions among
organisms and the environment.
What launched population
genetics in early 1900’s?
Synthesis of Mendelian genetics and Darwin &
Wallace’s evolutionary theory launched population
genetics in early 1900’s.
What is environmentalism?
the study of
ecological problems
in the human
context (including
economics, politics,
moral values, etc.)
* Situations may be
judged as good or
bad.
What are the 6 levels of organization in Ecology?
Individual, Population, Community, Ecosystem, Landscape, and biosphere/ecosphere
What are the different levels of studying in ecology?
Individual approach, Population approach, Community approach, Ecosystem approach, Landscape approach, and biosphere/ecosphere approach
What is the first law of thermodynamics?
Matter and energy cannot be created or destroyed, but can change form
What is a dynamic steady state?
Ecological systems gain and lose matter and energy.
A dynamic steady state occurs when gains and losses are in balance.
What is natural selection?
A change in the frequency of genes in a population
through differential survival and reproduction of
individuals that possess certain phenotypes.
What are the three requirements for natural selection?
- Individuals vary in their traits.
- Traits are heritable.
- Variation in traits causes some individuals to experience higher
fitness (survival and reproduction).
What are Producers (or Autotrophs)?
Species that convert
light or chemical energy into resources.
What are Consumers (or heterotrophs)?
Species that obtain their
energy from other organisms.
What are Mixotrophs?
Species that can switch between being
producers and consumers.
What are Scavengers?
Species that can consume dead animals.
What are Detritivores?
Species that break down dead organic
matter (i.e., detritus) into smaller particles
What are Decomposers?
Species that break down detritus into
simpler elements that can be recycled.
What is predation?
when an organism kills and consumes an individual
What is Parasitism?
when one organisms lives in or on another organism
What is Herbivory
: when one organism consumes producers.
What is Competition?
when two organisms have a negative effect on each other
because they depend on the same resource.
What is Mutualism?
when two species benefit from each
other.
What is Commensalism?
when two species live in close
association and one receives a benefit, whereas
the other is unaffected.
What is Amensalism?
when two species live in close
association and one receives a negative effect,
whereas the other is unaffected.
What is a habitat?
the place, or physical setting, where an organism lives.
Distinguished by physical features, such as dominant plant type.
What is a Niche?
the range of abiotic
and biotic conditions an organism can tolerate. (No two species have exactly the
same niche.)
What is Hutchinson’s n-dimensional niche?
the n-dimensional volume
representing the range of environmental conditions and resources
availabilities in which a species can persist
What is the Ecology Scientific Method?
Observation, induction, hypothesis or model, deduction, prediction, and experiment
Why are manipulative experiments often not possible in ecology?
The scale is too large and causal factors cannot be independently manupulated.
What are the alternatives to experiments?
Natural experiments, observational/correlational studies, and mathematical models.
What is a Natural Experiment?
an approach to hypothesis testing that
relies on natural variation in the environment to test a hypothesis.
What is an observational/correlational study?
Make deductions from patterns in nature. Care is needed; correlation between variables does not establish causation.
What is a mathematical model?
representations of a system with a set of
equations that correspond to hypothesized relationships among
the system’s components. Ecologists often test mathematic
models using natural or manipulative experiments.
What is a semipermeable membrane?
membranes that allow only particular molecules
to pass through; reduces free movement of solutes.
What is Osmosis?
net movement of water across a semipermeable membrane, towards
a higher solute concentration.
What is Osmotic Potential?
the force with which a solution attracts water by osmosis.
Expressed in units of pressure, such as megapascals (MPa)
fresh-water fish are ______ (dynamic steady state)
fresh-water fish are hyper-osmotic
(internal solute concentration higher
than that of surrounding water)
Marine fish are _______ (dynamic steady state)
marine fish are hypo-osmotic (internal
solute concentration lower than that of
surrounding water )
What is Osmoregulation?
: mechanisms organisms use to maintain a proper solute balance.
Explain the Osmoregulation of salt in Sharks and Rays?
Sharks and rays convert ammonia, a byproduct of protein digestion, into urea.
Most urea is excreted, but some is retained
in the bloodstream.
This raises the osmotic potential of their
blood to that of seawater, which balances
water movement.
They accumulate trimethylamine oxide in
blood to protect proteins from the harmful
effects of urea.
What is the thermal Optimum?
the temperature in which an organism best performs. Determined by the properties of an organism that influence the ability to
function
What does the thermal optimum curve look like?
A bell curve with a significant drop right of the optimal temperature
What is Electromagnetic Radiation?
Determined by the properties of an organism that influence the ability to
function
What is the photosynthetically active region?
wavelengths of light that are suitable
for photosynthesis; includes wavelengths from 400 nm (violet) to 700 nm
(red).
What are Chloroplasts?
specialized cell
organelles found in eukaryotic
photosynthetic organisms.
What colors do plants absorb best and worst?
Chlorophylls absorb red, blue and violet light,
and reflect green and yellow light.
What are the two stages of Photosynthesis?
Light and dark reactions?
what are Light Reactions?
convert energy from
photons into chemical energy
What are Dark Reactions?
(Calvin cycle) – use
chemical energy and CO2
to make sugar.
What are the 4 steps in light reactions?
- Chlorophyll in thylakoids absorbs photon energy.
- Chlorophyll releases electrons to a chain of reactions.
- In the process, H2O molecules are converted into H+
and O2
. 4. Energy from released electrons generate ATP and NADPH
Energy + ADP + Pi -> ATP
2 electrons + H+
+ NADP+ -> NADPH
What is the Calvin Cycle?
Takes place in the stroma of the chloroplast.
The energy in ATP and NADPH is used to convert CO2
into glucose.
What is C3 Photosynthesis
The Dark reaction where CO2
+ RuBP -> 2 G3P Process is catalyzed by RuBP carboxylase-oxidase
(also known as Rubisco).
Why is Rubisco outdated?
Rubisco originated when CO2 was ⁓1000x higher than today and O2 was nearly absent in
atmosphere
What are some disadvantages of C3 photosynthesis?
1) Rubisco has a low affinity for CO2
, so C3 plants must pack their cells with large amounts of Rubisco.
2) Rubisco also reacts with O2
resulting in photorespiration, which is costly for plants
What is Photorespiration?
: the process in which RuBP combines with a molecule of O2, resulting in the release of CO2
and loss of energy. It is catalyzed by Rubisco.
Photorespiration reverses the gains made by photosynthesis
Why is photorespiration more problematic in hot and dry conditions?
The tendency for Rubisco to react with O2
is greater when
1) O2
concentration is high
2) CO2
concentration is low
3) Temperature is high
When stomata are partially closed to conserve water under hot or dry conditions, CO2
concentrations in leaves will be low.
What is C4 photosynthesis?
: a photosynthetic pathway in which CO2
is initially assimilated into a four-carbon compound, oxaloacetic acid (OAA); provides an advantage in hot and dry conditions.
CO2 + PEP -> OAA
This is catalyzed by PEP Carboxylase, which has higher CO2affinity than Rubisco.
What are some advantages and disadvantages of C4 photosynthesis?
The 4-carbon compound is transported into bundle sheath cell where the calvin cycle occurs with a CO2 concentration that is 3-8 times higher than normal. This comes at the cost of using less cells for photosynthesis and using energy for the CO2 pump biochemistry
What is an example of a C3 plant?
wheat
What are some examples of a C4 plant?
maize, sorghum, sugar cane, millet
How old is C4 photosynthesis and how common is it?
30 million years old and independently evolved around 63 times.
What is CAM Photosynthesis?
CAM (crassulacean acid metabolism) photosynthesis: a
pathway in which the initial assimilation of carbon into OAA
occurs at night. Instead of separating the steps of CO2
assimilation between
mesophyll and bundle sheath cells, the steps are separated in
time.
During day, stomata close to reduce transpiration.
Stomata open to exchange gases during the night,
when cool temperatures slow transpiration.
What are some examples of CAM plants?
Cacti, pineapples, epiphytic orchids, and the Crassulaceae family
What are some structural adaptations to hot and dry environments?
-Shallow roots are able to take up water after brief rainfall events. Long
roots can access deeper waters.
-Resins and waxy cuticles protect plants from direct sunlight and slow
water loss.
-Spines and hairs provide protection and
produce a boundary layer of still air that
traps moisture and reduces evaporation.
-Small leaves with a high density of veins
prevent loss of leaf tissue via embolisms, or air bubbles in veins, which are common
in water-stressed environments.
What is Radiation?
the emission of electromagnetic energy by a
surface.
Increases with the fourth power of absolute temperature
What is Conduction?
the transfer of the kinetic energy of heat
between substances that are in contact with one another.
Conduction rate depends on surface area, resistance of
substances to heat transfer, and temperature differences
between substances.
What is Convection?
the transfer of heat by movement of liquids
and gases
What is Evaporation?
the transformation of water from a liquid to
a gaseous state with the input of energy; removes heat
from a surface.
Surface area (SA) of an organism increases as the _____
of its length (L).
Volume (V) increases as the ____ of L.
Surface area (SA) of an organism increases as the square
of its length (L).
Volume (V) increases as the cube of L.
What is thermal inertia?
Thermal inertia: the resistance to a change in
temperature due to a large body volume
What is thermoregulation?
the ability of an organism to control the temperature of its body.
What are homeotherms?
(homeo = similar) organisms that maintain constant temperature;
this allows biochemical reactions to work most efficiently
What are Poikilotherms?
(poikilo = varied) organisms that do not have constant body
temperatures.
What are endotherms?
(endo = internal) organisms that can generate metabolic heat to raise
body temperature higher than the external environment.
What are Ectotherms?
(ecto = external) organisms with body temperatures determined by
their external environment; usually, but not necessarily, poikilotherms.
What is blood shunting?
when specific blood vessels shut
off so less of an animal’s warm blood flows to
cold extremities where heat would be lost.
What is Countercurrent circulation?
helps to conserve heat by positioning arteries that
carry warm blood away from the heart
alongside veins that carry chilled blood from
the extremities back to the heart.
What is torpor?
The reduction in energy usage when resting
What is a phenotype?
an attribute of an organism, such
as its behavior, morphology, or physiology
What is phenotypic plasticity?
ability of a genotype toproduce multiple phenotypes in response todifferent environmental conditions
What is an Isozyme?
different forms of an enzyme that catalyze a reaction.
What is a microhabitat?
locations within a habitat that differ in
environmental conditions from the rest of the habitats.
What are the 4 mechanisms of evolution?
Natural selection, Migration, Mutation, and Genetic drift
What is genetic drift?
random change in population makeup (nothing to do
with animals drifting across the landscape)
What is migration?
movement of individuals (or pollen or seeds). If the
individual
What is mutation?
Random changes in genetic makeup of an in individual
What is natural selection?
Differential reproduction or survival, generally in response to the environment
