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Chapter 42: Circulation And Gas Exchange Most invertebrates have a gastronomical
cavity or a circulatory system for internal transport Gastrovascular cavities- A body
wall only two cells thick encloses a gastronomical cavity, which servers the dual
functions of digestion and substance distribution in the body.
Open and Close Circulatory systems
Hemolymph- general body fluid
Open circulatory system- In insects and arthropods, and most mollusks, blood bathes
the internal organs directly
Sinuses- Spaces surrounding the organs
Closed circulatory system- blood confined to vessels and has a heart pumping blood to
different systems
Vertebrate phylogeny is reflected in adaptations of the cardiovascular system
FISH
AMPHIBIAN
MAMMAL
Cardiovascular system- made up of the heart, blood vessels, and blood
Atrium(Atria)- The chambers that receive blood returning to the heart
Ventricles- The chambers that receive blood returning to the heart
Arteries- carry blood away from the heart to other organs
Arterioles- Branches of the arteries that convey blood into the capillaries
Capillaries- microscopic vessels with very thin, porous walls
Capillary beds- networks of capillaries where chemicals and gasses are exchanged
between the blood and interstitial fluid
Venules- The ending of capillaries that converge into veins
Veins- return blood to the heart
Pulmocutaneous circuit- frogs and other amphibians that have a three-chambered heart,
and this circuit leads to gas exchange tissues where the blood picks up oxygen as it flows
through capillaries
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Systemic circuit- carries
oxygen-rich blood to all body
organs then returns oxygenpoor blood to all body organs
Double circulation- ensures a
vigorous flow of blood to the
brain, muscles, and other
organs
Pulmonary circuit- in reptiles,
blood is conveyed from the
heart to the gas-exchange
tissues in lungs and back to the
heart
Double circulation in
mammals depends on the
anatomy and pumping cycle
of the heart The Mammalian Heart: A closer look
1) The right ventricle pumps blood to the longs via the pulmonary arteries
2) Blood flows through the capillary beds in lungs where it loads up on Oxygen and gets
rid of Carbon Dioxide
3) It returns from the lungs via the pulmonary veins to the left atrium of the heart
4) The oxygen-rich blood flows into the left ventricle
Atrioventricular (AV) valve- anchored by strong fibers, strong contractions of the
ventricles closes the AV valves, keeping blood from flowing back into the atria.
Semilunar valves- located at the two exits of the heart. The blood is pumped into the
arteries, via these valves, and is forced open when the pressure is created by ventricular
contraction.
Pulse- the rhythmic stretching of the arteries caused by the pressure of blood driven by
the powerful contractions of the ventricles
Heart Rate- the number of times the heart beats each minute
Cardiac cycle- one complete cycle of pumping and filling
Systole- a contraction phase
Diastole- a relaxation phase
Cardiac output- the volume of blood per minute that the left ventricle pumps into the
systematic circuit
Stroke volume- the amount of blood pumped by the left ventricle each time it contracts
Maintaining the Heart’s Rhythmic Beat1) The SA node sets the tempo of the heartbeat by
generating electrical signals
2) The electrical signals are spread through the atria, making them contract
simultaneously. At the AV node, there is a slight delay where the blood in the atria
empties into the ventricles
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3) Specialized muscle fibers (bundle branches and Purkinje fibers) then conduct the
signals to the apex of the heart and ventricular walls
4) The signals trigger both ventricles to powerfully contract, driving blood into the large
arteries
Sinoatrial (SA) node (Pacemaker)- a region of the heart that maintains the heart’s
pumping rhythm by setting the rate at which all cardiac muscles cells contract
Atrioventricular (AV) Node- a relay point where the impulses from the SA node go.
The impulses are delayed for about .1 sec, which make sure the atria will contract and
then empty before the ventricles contract.
Electrocardiogram (ECG or EKG)- electrodes placed on the skin and record the
electrical currents of the body
Structural differences of arteries, veins, and capillaries vessels correlated with their
different functions
Endothelium- a single layer of flattened cells that provides a smooth surface that
minimizes resistance to the flow of blood
Physical laws governing the movement of fluids through pipes affect blood flow and
blood pressure
Capillaries- lack 2 outer layers, very thin walls (only basement membrane and
endothelium)
Arteries- thicker middle and outer layers than veins
Blood Pressure
Blood Pressure- the hydrostatic force that blood exerts against the wall of a vessel
Peripheral resistance- the impendence by the arterioles
Transfer of substances between the blood and the interstitial fluid occurs across the
thin walls of the capillaries - At any given time, only about 5%-10% of the body’s
capillaries have blood flowing through them
A) When the precapillary sphincters are relaxed, capillaries branching from the
thoughtfare channel are open, and blood flows into the capillary bed
B) When the sphincters are contracted, the capillaries are closed, and blood flows through
the capillary bed is reduced
- Small molecules diffuse through the membrane of the cells, such as Oxygen and
CO2The lymphatic system returns fluid to the blood and aids in body defense
Lymphatic system- lost fluid and proteins return to the blood by diffusing into tiny
lymph capillaries that are intermingled among capillaries of the cardiovascular system
Lymph- fluid inside the lymphatic system
Lymph nodes- organs along a lymph vessel where filter the lymph.
Plasma- vertebrate blood is a type of connective tissue consisting of several kids of cells
suspending in a liquid matrix
Red Blood cells (erythrocystes)- the most numerous of the blood cells, that transports
oxygen and helps transports Carbon Dioxide
Hemoglobin- an oxygen carrying protein containing iron
White blood cells (Leukocytes)- helps with defense and immunity
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Platelets- blood clotting Pluripotent stem cells- a single population of cells in the red
marrow of bones (ribs, vertebrate, breastbone, pelvis)
Erythropoietin- a hormone that stimulates production of erythrocytes in the bone
marrow
Fibrinogen- a sealent for vessels
Fibrin- a plasma protein is converted to its active form which aggregates threads that
form the fabric of the clot
Hemophilia- a disease characterized by excessive bleeding from even minor cuts and
bruises Thrombusvascular diseases – disease of the heart and blood vessels
Heart Attack- the death of cardiac muscle tissue resulting from prolonged blockage of
one or more coronary arteries
Stroke- the death of nervous tissue in the brain, usually resulting from blockage of
arteries in the head
Hypertensions- high blood pressure that increases the risk of heart attack and stroke
GAS EXCHANGE IN ANIMALS (Pulled from another website)
Animals require oxygen because O2 is the final electron acceptor in the electron transport
chain, a metabolic pathway used by organisms to generate the bulk of their ATP
Without continuous supply of O2 they cannot not obtain enough energy from their food
to remain alive.
Energy metabolism also generates CO2 as waste.
Respiratory surface = part of animal where O2 diffuses into the animal and CO2 diffuses
out into the environment.
4 types of animal respiratory systems evolved
1. Entire outer skin: small animals, worms, flat worms, planarians, hydra; must live in
wet places; have enough surface to volume ratio.
2. Gills: feather-like extensions of body surface specialized for gas exchange; evolved
and are present in most aquatic animals (Fig 42.19).
3. Trachea: respiratory surface of insects; made up of extensive system of internal tubes
leading to several openings on body surface; variation on theme of folded internal
respiratory surface
4. Lungs: most terrestrial vertebrates have them; made up of internal sacs lined with
moist epithelium.
Tracheal system of insects is made up of tubes that branch out throughout the body
Mammalian respiratory system
Air enters the lung through a system of branching tubes when chest cavity increases in
volume as a result of muscular contractions by diaphragm and rib muscles
With exception of smallest bronchioles and alveoli, most epithelial cells lining respiratory
tract are covered with cilia and thin film of mucus
trachea; wind pipe; lined by cartilaginous rings to maintain shape.
bronchus 1 per lung. Splits into bronchioles
bronchiole; continue to split and become smaller until they terminate as alveoli
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alveoli: grape-like clusters of air sacs at ends of small bronchioles; surface where gas
exchange is actually carried out; highly capillarized.
capillaries; exchange gases with epithelial cells lining alveoli.
1. inhalation: sucking-in of air; chest cavity increases in size due to contraction of
diaphragm and rib muscles resulting in a decrease in air pressure in the lungs. Air flows
down its pressure gradient into lungs.
2. exhalation; relaxation of diaphragm and rib muscles decrease s size of chest cavity,
causing air to be expelled.
tidal volume = vol of air that animal inhales and exhales in each normal breath ( ~500ml)
Vital capacity = max volume of air that we can inhale and exhale (strenuous exercise.)
(3500-4800 ml )
500 ml breathing at rest
Residual volume = air that remains in the lung after forcefully blowing out as much air
as posssible. i.e lungs hold more volume than vital capacity due to dead air in
uncollapsed alveoli.
Emphysema = loss of resilience of in lung cells. Smoking makes walls of alveoli brittle
(lose elasticity) and some rupture, leading to reduced capacity for gas exchange.
Hyperventillation = breathing control centers no longer send signals to muscle cells
because rapid breathing purged too much CO2 from the body.
Gases diffuse down pressure gradients in the lungs and other organs
Partial pressure = portion of atmospheric pressure contributed by a certain gas.
Disorders of the Respiratory system
Reduced air flow or gas exchange impedes respiratory function.
Asthma: Spasmodic contraction of bronchi; reversible decrease in gas exchange surface;
becoming more common;bronchodialators standard therapy.
Emphysema: Alveoli become permanently impaired as result of loss of elasticity;
permanent decrease in gas respiratory surface; common in smokers; leads to
cardiovascular disease.
Bronchitis: inflamation of bronchi; heavy mucous and cough; common in smokers.
Pneumonia: inflamation of lungs due to infection; viral or bacterial.
Tuberculosis: infectious lung disease caused by Mycobacterium tuberculosis; easily
treatable, but becoming more common.
Botulism: form of food poisoning caused by Clostrridium botulinum; toxin blocks
transmission of nerve signals to skeletal muscles.
Congestive heart failure: backpressure from heart moves fluids into the lungs
Cystic fibrosis: Defective ion channel upsets water relations; excessive build up of
mucus in bronchi and parabronchi; most common genetic disorder in N. America;
recessive.
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Chapter 48: Nervous SystemsNervous systems perform the three overlapping
functions of sensory input, integration, and motor output
Central nervous system (CNS)- the brain and spinal cord
Effector Cells- the muscle cells or gland cells that actually carry out the body’s
responses to stimuli Neuron-the functional unity of the nervous system specialized for
transmitting signals from one location in the body to another
Peripheral nervous system (PNS)- the nerves that communicate motor and sensory
signals between the CNS and the rest of the body
Dendrites- convey signals from their tips to the rest of the neuron
Axons- which conduct messages toward their tips
Myelin Sheath- an insulating layer that enclose the vertebrate nervous system
Schwann cells- supporting cells that form myelin sheaths
Oligodendrocytes- supporting cells that help to produce the myelin sheaths
Synaptic terminals- endings of the axons that relay signals to other cells be releasing
chemical messengers called neurotransmitters
Synapse- The site of contact between a synaptic terminal and a target cell
Sensory Neurons- communicate information about the external and internal
environments from sensory receptions to the CNS
Interneurons—integrate sensory input and motor output (they make synaptic
connections only with other neurons)
Motor neurons- convey impulses from the CNS to effector cells
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Chapter 49: Sensory And Motor Mechanisms Hydrostatic skeletons
Hydrostatic skeleton- consists of fluid held under pressure in a closed body
compartment, the main type of skeleton in most cnidarians, flatworms, nematodes, and
annelids
Peristalis- a type of locomotion produced by rhythmic waves of muscle contractions
massing from head to tail (earthworms)
Exoskeleton- a hard encasement deposited on the surface of an anima (Mollusk, beetles)
Cuticle- a nonliving coat secreted by the epidermis
Chitin- a polysaccharide similar to cellulose
Endoskeleton – consists of hard supporting elements, such as bones, buried within the
soft tissues of an animal
Skeletal Muscle- attached to the
bones and is responsible for their
movement
Myofibrils- tiny fibers that are in
skeletal fibers
Myofilaments- Two types of filaments- thick and thin,
Thin filaments- actin and regularatory proteins collided around each other
Thick filaments- myosin molecules
Sarcomere- the basic functional unit of the muscle, a repeating pattern of dark and light
lines
Z lines- the borders around the sarcomere,
I band- the area near the edge of the sarcomere where there are only thin filaments
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A band- the broad region that corresponds to the length of the thick filaments H zonethe center of the A band that contains only thick filaments
Sliding-filament
model- the thin
and thick
filaments do not get smaller, they just slide past each other when the muscle contracts.
Cross-Bridge- the sites where energized myosin binds to a specific site on the actin
Phosphagens- where muscle cells store glycogen needed for repetitive muscle
contractions
Creatine Phosphate- the phosphagens of vertebrates, can supply a phosphate group to
ADP to make ATP Calcium Ions and regulatory proteins control muscle contraction
Tropomyosin- the regulatory protein that blacks the myosin binding sites on the actin
molecules
Troponin complex- controls the position of tropomyosin on the thin filament
Sacroplasmic reticulum- a specialized endoplasmic reticulum that transports calcium
from the cytoplasm into the interior of the reticulum
T (Transverse) tubules- infoldings of the plasma membrane where the tubules contact
the sarcoplasmic reticulumDiverse body movements require variation in muscle
activity
Motor unit- consists of a single motor neuron and all the muscle fibers it controls
Recruitment- tension in a muscle that can be increased by activating more and more of
the motor neurons controlling the muscle
Fast and Slow Muscle Fibers
Fast Muscle fibers- used for rapid, powerful contractions
Slow muscle fibers- can sustain long contractions, often found in muscles that maintain
posture
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Other types of muscle
Cardiac Muscle- found only in the heart, striated
Intercalated discs- junctions between cardiac muscles cells where gap junctions can
provide direct electrical coupling among cells
Smooth Muscle- lacks the striations of skeletal and cardiac muscle
Chapter 50: An introduction to ecology and the biosphere
Ecology is the scientific study of the interactions between organisms and their
environment
Abiotic components- nonliving chemical and physical factors (light, temperature, water,
nutrients)
Biotic components- all the other organisms that are part of any individual’s
environments
Ecological research ranges from the adaptations of organisms to the dynamics of
ecosystems
Organismal ecology- concerned with the behavioral, physiological, and morphological
ways in which individual organism meet that challenges posed by their abiotic
environment
Population- a group of individuals of the same species living in a particular area
Community- consists of all the organism that inhabit a particular area
Ecosystem- a study that includes all abiotic factors in addition to the community of
species that exists in a certain area
ABIOTIC FACTORS OF THE BIOSPHERE
Biosphere- the global ecosystem, the sum of all the planet’s ecosystems, or all of life and
where it lives
Climate and other abiotic factors are important determinates of the biosphere’s
distribution of organisms.
Major abiotic Factors
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TEMPERATURE- Certain organisms need certain temperatures to live in; most
organisms cannot live in extreme high or low temperatures. Organisms function best
within certain environmental temperatures
WATER- The availability of water varies among habitats, and most habitats are shaped
by organisms requirements for obtaining and conserving water supplies
SUNLIGHT- Provides the energy to fuel most ecosystems, although only photosynthetic
organisms use the sun directly.
WIND- Amplifies the environmental temperature, contributes to water loss by increasing
the rate of evaporation, hold an effect on growth form of plants
ROCKS AND SOIL- Physical structure, pH, and mineral composition of rocks and soil
limit plant distribution, animals that feed off of them.
PERIODIC DISTRUBANCES- Hurricanes, fires, volcanic, tornadoes, and other
disturbances
Climate and the distribution of organisms
Climate- the prevailing weather conditions at locality, affected by water, light, and wind,
and temperature
Biome- A major type of ecosystem, those that occupy geographic regions
Global Climate Patterns
Tropics- regions between 23.5 N latitude and 23.5 S latitude
Local and Seasonal Effects on Climate
Turnover- during the summer and winter, many lakes in temperate regions are thermally
stratified, of layered vertically, according to temperature. Such lakes undergo a biannual
mixing of their waters as a result of changing water-temperature profiles. It brings
oxygenated water from the surface of lakes to the bottom and nutrient rich water from the
bottom to the top
AQUATIC AND TERRESTRIAL BIOMES
Aquatic biomes occupy the largest part of the biosphere
Vertical stratification of aquatic biomes
Photic zone- where there is sufficient light for photosynthesis
Aphotic zone- little light penetrates
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Thermocline- a narrow stratum of rapid temperature change that separates a more
uniformly warm upper layer from more uniformly cold deeper waters
Benthos- a community of organism in the benthic zone
Benthic zone- the substrate at the bottom of all aquatic biomes
Detritus- a source of food for the benthos that is made up of dead organic matter
Freshwater Biomes
Littoral Zone- the shallow, well-lit waters close to shore
Limentic zone- open surface waters further from shore
Profundal Zone- deep aphotic zone
Oligotrophic- a type of lake that is deep and nutrient poor
Eutrophic- usually more shallow that oligotrophic, and have a high nutrient content
Mesotrophic- In between the oligotrophic and eutrophic levels of deepness and nutrient
content
Wetland- an area covered with water that supports aquatic plants
Estuary- the area where a freshwater stream or river merges with the ocean, often
bordered by extensive coastal wetlands called mudflats and salt marshes
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Intertidal zone- Zone where land meets
water
Neritic Zone- the shallow regions over
the continental shelf
Oceanic zone- past the continental zone that reaches very deep
Pelagic zone- the open water of any depth
Benthic Zone- the bottom of the seafloor
Oceanic pelagic biome- most of the ocean’s water, far from shore, that is constantly
mixed by ocean currents
Benthos
Abyssal Zone- the deep benthic zone, where organisms are adapted to cold, high water
pressure, and near or total absence of light, and low nutrient content.
-Here, there are chemoautotrophic prokaryotes
The geographical distribution of terrestrial biomes is based mainly on regional
variations in climate
Canopy- the upper part of the forest, the top layers of the trees that cover the entire forest
Permafrost- permanently frozen stratum
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CONCEPTS OF ORGANISMAL ECOLOGY
The costs and benefits of homeostasis affect an organism’s responses to
environmental variation
Regulators- they use behavioral and physiological mechanisms to achieve homeostasis
in the face of environmental fluctuations in temperature, moisture, light intensity, and
concentrations of a variety of chemical factors
A) Tropical Forests- Rainfall is extremely variable, prime determinate of the vegetation
growing there. Plants are thorny shrubs, trees and succulents. In areas with distinct wet
and dry seasons, tropical deciduous trees are common
B) Savanna- Large showcase of large herbivores and their predators, many insects, ants
and termites. Grasses and scattered trees, fire is an important factor as many things are
fire-adapted. Often periods of seasonal drought
C) Desert- Some rainfall, cacti, rooted shrubs, many plants use CAM photosynthesis,
many protective adaptations deter mammals and insects feeding on them (spines and
poisons)
D) Chaparral – Dense, spiny, evergreen shrubs, mild rainy winters, and long, hot, dry
summers, often brushfires, so things are adapted to that, some seeds can only germinate
after a hot fire.
E) Temperate Grassland- Plains and prairies, seasonal drought, occasional fires, large
mammals, few woody shrubs and trees, soil is often deep and rich in nutrients
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F) Temperate Deciduous Forest- Dense strands of deciduous trees, distinct layers and
seasons
G) Coniferous Forest- cone bearing trees, pine, spruce, fir, and hemlock, frequently
logged
H) Tundra- permafrost, bitterly cold temperature, high winds, shallow topsoil
Conformers- organisms that call allow some conditions within their bodies to vary with
external changes
Principle of allocation- organisms have a limited amount of energy that can be allocate
for obtaining nutrients, escaping from predators, coping with environmental fluctuations,
growth, and reproduction
Acclimation- involves substantial but reversible change that shift an organisms tolerance
curve in the direction of the environmental change
Chapter 52 Population Ecology
Two important characteristics of any population are density and the spacing of
individuals
Population- a single species that occupy the same area
Density- the number of individuals per unit area or volume
Dispersion- the pattern of spacing among individuals within the geographical boundaries
of the populations
Measuring Density
Mark-Recapture Method- tagging a certain amount, and then using (number marked
times total catch second time) divided by number of marked recaptures
Patterns of Dispersion
Grain- one which the environmental patches are so large that an individual organism can
distinguish and chose among patches
Clumped- Strong attractions to each other
Uniform- evenly spaced organisms
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Random- random spacing, with no strong attraction or repulsion
Biogeography- the factors that influence the distribution of a species over its range are
the subject
Demography is the study of factors that affect the growth and decline of populations
Demography- the study of vital statistics that affect population size
Age Structure and Sex Ratio
Age Structure- the relative number of individuals of each age
Birthrate (Fecundity)- the number of offspring produced during a certain amount of
time
Death Rate- the number of deaths in a certain amount of time
Generation Time- the average span between the birth of individuals and the birth of their
offspring
Sex Ratio- the proportion of individuals of each sex
Cohort- a group of individuals of the same age, from birth, until death
Survivorship Curve- a plot of the numbers
in a cohort still alive at each age
LIFE HISTORY TRAITS
Life History- the traits that affect an organism’s schedule of reproduction and death
Number of reproduction episodes per lifetime
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Smeelparity- expend their energy in one large reproductive effort, and then die
Iteroparity- organisms that produce fewer offspring at a time over a span of many
seasons
An exponential model of population growth describes an idealized population in an
unlimited environment
Intrinsic Rate of increase- the maximum population growth rate
Exponential population growth- population increase under certain conditions
A logistic model of population growth incorporates the concept of carrying capacity
Carrying capacity- the maximum population size that a particular environment can
support with no net increase or decrease over a relatively long period of time
Logistic population growth- incorporates the effect of population density
Population Growth Models and Life Histories
Equilibrial populations (k-selected- are those that are likely to be living at density near
the limit imposed by their resources
Opportunistic populations (r-selected)- likely to be found in variable environments in
which population densities fluctuate
POPULATION LIMITING FACTORS
Density-Dependent Factors regulate population growth by varying with the density
Intraspecific competition- the reliance of individuals of the same species on the same
limited resources
Density-Dependent factor- one that intensifies as the population increases in size
The occurrence and severity of density-independent factors are unrelated to
population density
Density-independent factors- unrelated to population size
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Chapter 53: Community Ecology
Species Richness- the number of species contained
Species diversity- the species richness and relative abundance
The interactive and individualistic hypotheses pose alternative explanations of
community structure: science as a process
Individualistic hypothesis- Gleason’s idea that community was a chance assemblage of
species found in the same area simply because they happen to have similar abiotic
requirements (temp, rainfall, soil type)
Interactive hypothesis- Clement’s idea was that the community was an assemblage of
closely linked species that cause the community to function as an integrated unit
INTERACTIONS BETWEEN POPULATIONS OF DIFFERENT SPECIES
Coevolution- describes interactions involving reciprocal evolutionary adaptations in two
species
Interspecific interactions may have positive negative, or neutral effects on a
population’s density: on overview
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Interaction
Predatation +/Commensalism +/o
Competition -/Mutualism +/+
Effects on Population Density
Helps one, hurts the other
One species helps the other is unaffected
Both are hurt
Both are helped
Predication and parasitism are +/- interactions: a closer look
Predatation- a predator and prey relationship
Parasitism- specialized kinds of predators called parasites that live in or on their hosts
Parasitoidism- insects that lay eggs on living hosts
Herbivory- animals eating plants
Plant Defense Against Herbivores
- Some plants store poisons, other chemical weapons of defense
Animal Defenses Against Predators
Cryptic Coloration- camouflage can make the potential prey difficult to spot against its
background
Aposematic coloration- a warning to predators by taking on bright warning colors
- Deceptive coloring can resemble the eyes of a much larger animals or something else
Mimicry- an organisms bears superficial resemblance to another species
Batesian mimicry- a palatable or harmless species mimics a harmful model
Mullerian mimicry- two ore more unpalatable, aposematically colored species that
resemble each other
Parasitisim
Endoparasites- parasites that live inside their hosts
Ectroparasites- parasites that feed on the external surface of a host
Interspecfic competitions are -/- interactions: a closer look
Interspecific competition- populations of two or more species in a community rely on
similar limiting resources
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Interference competition- competition that can occur in different ways
Exploitive competition- the consumption or use of similar resources
The competitive exclusion principal
Competitive exclusion principle – the idea that when two organisms exist and compete
against each other, one of them will perish
Ecological Niches
Ecological niche- the sum total of the organism’s use of the biotic and abiotic resources
in its environment
Fundamental Niche- refers to the set of resources a population is theoretically capable
of using under ideal circumstances
Evidence for Competition in Nature
Resource partitioning- sympatric species consume slightly different foods or use other
resources in slightly different ways
Character displacement- the idea that characteristics tend to be more divergent in
sympatric populations of two species than in allopatric populations
Commensalism and mutualism are +/0 and +/+ interactions, respectively: a closer
look
Symbiosis – ‘living together’ is a term that encompasses a variety of interactions in
which two species host and symbiotic, maintain a close association
Parasitism- one organism harms the host
Commensalism- one partner is benefit, the other one isn’t affected
Mutualism- both partners benefit
Predators can alter community structure by moderating competition among prey
species
Keystone species- a species that makes an unusually strong impact on community
structure
DISTURBANCE AND NONEQUILIBRIUM
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Stability- the context is the tendency of a community to reach and maintain an
equilibrium
Nonequilibrium resulting from disturbance is a prominent feature of most
communities
Disturbances- the events, such as storms, fire, floods, droughts, and overgrazing that
damage communities
Succession is a process of change that results from disturbances in communities
Ecological succession- transitions in species composition over ecological time represent
a process
Primary Succession- the process where a lifeless area springs life
Secondary succession- occurs where an existing community has been cleared by some
disturbance that leaves the soil intact
The nonequilibrial model views communities as mosaics of patches at different
stages of succession
Recruitment- disturbances that trigger major changes in community structure generally
are those whose magnitude or frequency results in colonization of disturbed patches
Dynamic Equilibrium Hypothesis- species diversity depends mainly on the effect of
disturbance on the competitive interactions of populations
Intermediate disturbance hypothesis- species diversity is greatest where disturbances
are moderate in both frequency and severity
COMMUNITY ECOLOGY AND BIOGEOGRAPHY
Dispersal and survivability in ecological and evolutionary time account for the
geographical ranges of species
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Chapter 54: Ecosystems
Trophic Structure- feeding relationships
Trophic levels- basis of organisms main source of nutrition
Trophic relationships determine an ecosystem’s routes of energy flow and chemical
cycling
Primary Producers- autotrophs, that use light energy to make sugars and other organic
compounds
Primary Consumers- Herbivores, which eat plants or algae
Secondary Consumers- carnivores that eat herbivores
Tertiary Consumers- carnivores that eat other carnivores
Detritivores- consumers that derive their energy from detritus
Detritius- non living organic material, such as feces, fallen leaves, and the remains of
dead organisms
Food Chain- the pathway along which food is transferred from trophic level to trophic
level
Food Webs- feeding relationships, the producer- primary consumer  secondary
consumer
Production- the rate of incorporation of energy and materials into the bodies of
organisms
Consumption- loosely defined by generally refers to metabolic use for growth and
reproduction of assimilated organic materials
Decomposition- the breakdown of organic materials to inorganic ones
Primary Producers include plants, algae, and many species of bacteria
- Limnetic Zone- phytoplankton
- Aphotic zone- deep sea, that depends on the photic zone
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Primary Productivity
Primary Productivity- amount of light energy converted to chemical energy by the
autorophs of an ecosystem
Gross Primary Productivity (GPP)- another word for the primary productivity
Net Primary Productivity (NPP)- equal to the gross primary productivity
Biomass- energy per unit area per unit time
Standing crop biomass- total biomass of photosynthetic autorophs present at a given
time
Limiting nutrient- the single nutrient that runs out of adequate supply first
As energy flows through an ecosystem, much is lost at each trophic level
Secondary Productivity
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Secondary Productivity- the rate at which an ecosystem’s
consumers convert the chemical energy of the food they eat
into their own new biomass
Ecological Efficiency and Ecological Pyramids
Ecological Efficiency- the percentage of energy transferred from one trophic level to the
next
Pyramid of productivity- the multiplicative loss of energy from a food chin, where the
trophic levels are stacked in blocks
Biomass pyramid- each tier represents the standing crop biomass
Turnover time- the lower standing crop biomass compared to productivity
Pyramid of numbers- the size of each block is proportional to the number of individual
organisms present in each trophic level
CYCLING OF CHEMICAL ELEMENTS IN ECOSYSTEMS
The Water Cycle
The Carbon Cycle
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The Nitrogen Cycle
Nitrogen Fixation- convert N2 into minerals that can be used to synthesize nitrogenous
organic compounds
Nitrification- turning ammonium to nitrite to nitrate (No2) to (NO3)
Denitrification- some nitrate is turned back to N2
Ammonification- process of decomposition of organic nitrogen back to ammonium
The Phosphorus Cycle
Field experiments reveal how vegetation
regulates chemical cycling: science as a
process
Long-Term ecological research (LTER)their job is to track the dynamics of natural ecosystems over relatively long periods of
time
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Chapter 55: Conservation Biology
The major threats to biodiversity and habitat destruction, overexploitation, and
competition by exotic species
- The Nile Perch- introduced into Lake Victoria, and the introduced perch annihilated the
cichlid populations, destroying the native fish and its own food supply
- March of the Fire ants- accidentally imported and spread through the Eastern United
States in a short amount of years 1956-1994
Biodiversity is vital to human welfare
- The rosy periwinkle, helps to sure Hodgkin’s disease and acute lymphocytic leukemia
THE GEOGRAPHIC DISTRIBUTION OF BIODIVERSITY
Gradual variation in biodiversity correlated with geographical gradients
1. Energy availability- increased solar radiation in the tropics increases the
photosynthetic activity of plants, providing an increases resources base for other
organisms and thus a capacity to sustain more species
2. Habitat heterogeneity- compared to other areas, tropical regions commonly experience
more local disturbances, and have greater environmental patchiness, allowing a greater
diversity of plant species to form the resources base for diverse communities of animals
3. Niche specialization- tropical climates may allow many organism to specialize on a
narrower range of resources.
4. Population interactions diversity is, in a sense, self-propagating because complex
population interactions coevolved and the resulting predator-prey and symbiotic
interactions in a diverse community prevent any populations from becoming dominant
Biodiversity hot spots have high concentrations of endemic species
-Biodiversity Hot spot- Any area that is relatively small but with an exceptional
concentration of species
Endemic species- species that are found in only one place and nowhere else
-Such species are normally found on islands, making them extremely likely to extinction
Migratory species present special problems in conservation
- The Monarch butterflies are hard because they migrate from the United States to
Canada, and then to Mexico and California, so conservation efforts must take place in all
of their migratory locations
CONSERVATION AT THE POPULATION AND SPECILES LEVELS
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Endangered species- an animal that is ‘in danger of extinction throughout all or a
significant portion of its range’
Threatened Species- any animals that are likely to become endangered in the foreseeable
future
The dynamics of subdivided populations apply to problems caused by habitat
fragmentation
Metapopulation- a subdivided population of a single species, and vary depending in part
on the size, quality, spatial arrangement, and persistence of habitat patches
- Often happens when human activity interferes and cuts off part of the population from
the other, essentially separating the species
Source and Sink Dynamics in Metapopulations
Source Habitat- an area of a habitat where a population’s reproductive success exceeds
morality and from which excess individuals disperse
Sink Habitat- a habitat where mortality exceeds reproductive success
Population viability analyses examine the chances of a species persisting or
becoming extinct in the habitats available to it
Population viability analysis (PVA)- a method of predicting whether or not a species
will persist in a particular environment
- Takes into account genetic variability, life history characteristics, sex rations, age at first
reproductions, fecundity, average birthrates, average death rates
Estimating minimum viable population size (MVP)
Minimum viable population size (MVP)- the smallest number of individuals needed to
perpetuate a population
Minimum dynamic area- the amount of suitable habitat needed to sustain a viable
population
Estimating Effective Population Size (Ne)
Effective Population Size (Ne)- based off the number of adults that successfully breed
Analyzing the viability of selected species may help sustain other species: science as a
process
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CONSERVATION AT THE COMMUNITY, ECOSYSTEM, AND LANDSCAPE
LEVELS
Landscape ecology- the application of ecological principles to the study of land use
patterns
Edges and corridors can strongly influence landscape biodiversity
Movement corridor – a narrow strip or series of small clumps of quality habitat
connecting otherwise isolated patches
- Corridors can promote dispersal and help sustain metapopulations
Nature reserves must be functional parts of landscapes
Zoned reserve systems- protected areas are surrounded by lands that are used and
altered more extensively by human activity
- The challenge is to develop in the surrounding lands a social and economic climate that
sustains itself while remaining compatible with the long-term viability of the protected
core area
Restoring degraded areas in an increasingly important conservation effort
Restoration ecology- a subdivision of conservation biology that applies ecological
principals in developing ways to return degraded ecosystems back to their original states
Bioremediation- the use of living organisms, usually prokaryotes, fungi, or plants, to
detoxify polluted ecosystems
Sustainable development goals are reorienting ecological research and will require
changing some human values
Sustainable development- the long term prosperity of human societies and the
ecosystems that support them
Sustainable Biosphere Initiative- a research agenda that aims to define and acquire the
basic ecological information necessary for the intelligent and responsible development,
management, and conservation of Earth’s resources
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