What determines the number of individuals in a population?
Birth rate
mortality rate
Immigration
Emigration
2 LIFE TABLES.
NAME THEM AND WHY IS ONE BETTER?
TIME..AT ONE TIME AT AGE OF DEATH
AGE..FOLLOW COHORT THRU TIME
AGE SPECIFIC IS BETTER.
ALL ASSUME SEASONAL VARIATION!
EXAMPLES:
TREES AND RINGS.
DEER AND LOWER JAW.
FISH RINGS ON SCALES.
IS dX OF THE LIFE TABLE COMPARABLE AMONG POPULATIONS?
WHY?
NO.
DEPENDS ON THE NUMBER YOU START WITH.
IN THE LIFE TABLE WHY IS qX COMPAREABLE AMOUNG POPULATIONS?
QX IS A RATE!
SURVIVORSHIP IN LIFE TABLE.
STATE EQUATION
lX=nX/nO
WHEN N
x IS NUMBER ALIVE AT START.
WHAT ARE THE 3 TYPES OF FUNCTIONAL RESPONSES.
1. Type I – convex....K SELECTIVE. PARENTAL INVESTMENT
2. Type II – diagonal
3. Type III – concave...r SELECTIVE...TREES ARE TYPE 3 AS WELL.
THE MOST BASIC DEMOGRAPHIC EQUATION
DENSITY (OF A UNIT AREA) =
(BIRTH +IMMIGRATION) - (DEATH + EMIGRATION)
OR....
D = IN - OUT
In nature, X - X year and X-X year
cycles have been widely recognized at northern latitudes for a variety of birds
and mammals.
3-4 AND 9-10
WHY DO CYCLES APPEAR TO AFFECT POPULATIONS?
The cycles appear to be the result
of synergistic interactions between food availability and predation.
DEFINE Exponential population growth.
a curve representing
the number of individuals in a population that becomes steeper and steeper over
time.
Differential equation
- assumes continuous reproduction
DN = rN.
Dt
IN EXPONENTIAL GROWTH, r DEFINES WHAT?
natural increase or biotic potential {r}
IF r=0 ON THIS CHART WHAT WOULD LINE LOOK LIKE?
FLAT
IF r =( - NUMBER) ON THIS CHART WHAT WOULD LINE LOOK LIKE?
LINE WOULD GO DOWN.
Very high intrinsic rates of
increase {r} can lead TO WHAT?
chaotic population dynamics.
R >7 AT LEAST.
DEFINE CHAOS
the tendency of simple, deterministic systems under some circumstances to exhibit complicated and effectively unpredictable dynamics.
DEFINE NUMERICAL RESPONSE
when predator numbers respond to changes in prey numbers, i.e., prey go up, predator increase; prey go down, predator decrease.
Ways in which animals try to reduce predation:
1. Cryptic coloration
2. Aposematic coloration
3. Aggressive resemblance
4. Mimicry
WHEN LOOKING AT A GROWTH CHART, THE INCREASE IN THE POPULATION FROM THE START IS SLOW.
WHAT TYPE OF SPECIES IS IT ? r OR K?
K
PARENTIAL INVESTMENTS.
ELEPHANTS.
LEMA PLANT, r OR K?
r FAST GROWTH.
DEFINE Logistic population growth
a population that begins to grow exponentially, then begins to level off as it approaches the carrying capacity.
Logistic population growth is represented by an S-shaped or sigmoidal curve.
DEFINE ALLEE EFFECT
A distinction is made between a "strong Allee effect", where a population exhibits a "critical size or density
DEFINE TIME-LAGS
the result of delayed feed-back in population density; can result in population
fluctuations.
DEFINE Population regulation
the process by which environmental interactions determine the density of a population.
HISTORICALLY, IT WAS VIEWED AS RESULTING IN EQUILIBRIUM (POPULATION) DYNAMICS.
DEFINE Density-dependence
A factor or factors affecting population size whose intensity of action varies with density; that is, densities at time t influence densities at time t + x.
PRESENT EFFECT FUTURE. THINK ABOUT THE K CAPACITY.
GRIME TRIANGLE. COMPETITION FROM OTHERS.
DEFINE Density-independence
having influence on individuals in a population that does not vary with the degree of crowding.
THINK GRIME'S TRIANGLE. STRESS, COMPETITION AND DISTURBANCE.
DENSITY INDEPENANCE= STRESS OR DISTURBANCE. SOMETHING OUTSIDE OF THE POPULATION IS WORKING IT DOWN.
NON EQUILIBRIUM DYNAMICS = DENSITY INDEPENDENCE.
IN REGURDS TO GRIMES MODEL WHAT 2 FACTORS RELATE TO DENSITY INDEPENDANCE?
DENSITY INDEPENANCE= STRESS OR DISTURBANCE. SOMETHING OUTSIDE OF THE POPULATION IS WORKING IT DOWN.
IN REGARDS TO NON-EQUILIBRIUM DYNAMICS, WHAT CORRELATES TO IT:
DENSITY DEPENDANT OR INDEPENDENT?
INDEPENDENT.
THINK HURRICANE COME ALONG, THAN A FIRE.
POPULATION KEEPS ON GOING BUT NO INTERNAL COMPETITION.
WHAT WOULD A CHART LOOK LIKE FOR A DENSITY DEPENDANT BIRTH/ DEATH RATE LOOK LIKE?
IF THE BIRTH AND DEATH RATE WERE INDEPENDENT, WOULD THEY CROSS ON A CHART?
NO.
NO EQUILIBRIUM POINT.
BOTH BOUNCE ALL OVER THE CHART.
DENSITY DEPENDANT OR INDEPENDENT?
DEPENDANT.
T OR F
Population dynamics resulting from density-independent factors have generally been assumed to be nonequilibrium dynamics.
TRUE
Density-independent population dynamics can result from:
1. Fire
2. Floods
3. Ice-storms
Density-dependent factors may be divided into two categories.
NAME THEM
1.Extrinsic – the population’s response to interaction with other members of the community.EXTERNAL
2. Intrinsic-the populations own response to its density.
DEFINE EXTRINSIC AND GIVE 4 EXAMPLES.
Extrinsic – the population’s response to interaction with other members of the community.
Extrinsic factors:
1. Predation
2. Parasitism
3. Interspecific competition
4. Disease
DENSITY DEPENDANT OR INDEPENDENT?
DENSITY DEPENDANT.
DEPENDANT UPON THEIR FOOD.
DEFINE INTRINSIC AND GIVE 6 EXAMPLES.
the populations own response to its density.
Territoriality..COUGAR/MULE
Reproductive inhibition... FEMALE MOUSE/HORMONES
Dispersal...MOLES..TO HIGH..TAKE OFF.
Stress..RABBITS..HORMONES..CORTICAL STEROIDS.
Ideal free distribution...WOOD LOTS. DISTRIBUTION OF DENSITY.
Intra-specific competition...FROM SPECIES OF SAME POPULATION.
DENSITY DEPENDANT OR INDEPENDENT ?
BOTH!
DIFFERENT MECHANICS!
1ST PEAK IS DEPENDANT..POP EFFECTED SIZE.
2ND INDEPENDENT...WAS EXTERNAL, WEATHER.
DEFINE Intraspecific competition AND THE 2 TYPES.
Intraspecific competition –competition between members of the same species for a limiting resource.
1.Exploitation – using up the resource before other individuals obtains access (scramble). GET IT 1ST.
2. Interference –involves direct interaction among competing individuals of the same species (contest). FIGHT.
IN SOURCE/SINK DYNAMICS, Source population : birth rate > death rate; population regulated by WHAT?
emigration.
WILL STAY WITHIN RANGE.
IN SOURCE/SINK DYNAMICS, Sink population : birth rate < death rate; population maintained by WHAT?
immigration.
NOT REGULATED.
CAN BECOME EXTINCT.
DEFINE META-POPULATIONS AND WHAT CAN RESULT FROM THEM.
spatially subdivided populations that are interconnected by occasional dispersal events.
occasional dispersal events can result in recolonization of patches in which populations have gone extinct.
DEFINE COMMENSALISM
STRONG SPECIES IS NOT EFFECT WHILST WEAKER SPECIES BENEFITS.
BIRDS ON A WATER BUFFALO.
SHARK AND THE RAMORAS.
DEFINE Optimal foraging
a set of rules, including breadth of diet, by which organisms maximize food intake per unit of time or minimize the time required to meet their food requirements.
DEFINE CURRENCY
a measure of what the individual is trying to maximize; traditionally this was energy; more recently fitness.
Biased Random Walk occurs when?
movement towards a particular point.
Correlated Random Walk occurs when?
subsequent movements influenced by previous movement.
WHAT THE HELL IS A BCWA
BCWA = Biased Random Walk + Correlated Random Walk
WHO?
Degu
Octodon degus
DEFINE " GIVING UP DENSITIES"
The level at which an individual ceases to use a particular resource.
Resources interspersed among a matrix.
Based on optimal foraging theory.
IN A GIVING UP DENSITY(SEEDS) GRAPH, THE LOWER OR SMALL THE NUMBER THE MORE FEEDING OCCURS.
TRUE OR NOT?
TRUE.
SHOW HOW MUCH FOOD IS LEFT TO CONSUME IN EACH INSTANCE.
INTERPRET THIS GRAPH IN REGARDS TO THE PREDATORS INFLUENCE.
THE DEGUS FED MORE WHEN THE PREDATORS WERE TAKEN OUT.
REMEMBER THAT THE GUD SHOW WHAT WAS LEFT AFTER FEEDING!!!
2 TYPES OF COMPETION?
ENTRINISTIC (IN)
EXTRINSTIC (OUT)
WHAT TYPE OF COMETITION WAS SHOWN BTN
Octodon degus (DAY) AND Phyllotis darwini (NITE)?
SCRAMBLE COMPETITION.
WHO GETS IT FIRST.
ACCORDING TO THIS GRAPH, WHERE WAS FEEDING DONE MORE?
ELEVATED.
LOWER NUMBER SHOWS WHAT'S LEFT AFTER FEEDING.
TWO TYPES OF HERBIVORY
Grazers – eat herbaceous plants such as grasses and forbs, e.g., bison and grasshoppers.
Browsers – eat leaves and
twigs of woody material, e.g., deer.
Although many herbivores can be considered grazers or browsers, types of herbivory are much more wide ranging
NAME SOME!
Frugivory
Seed predation
Nectivores
Leaf mining
Roots
Sap suckers..WOODPECKER AND APHIDES
Herbivory can affect the distribution and abundance of plants in a variety of different ways,
NAME 4
1. significant reductions in density
2. altering growth forms
3. reductions in biomass
4. changes in interspecific competition.
T OR F
Frugivory can be a form of mutualism?
TRUE.
ANIMAL DISPERSES THE SEEDS
NAME 3 DEFENSES THAT PLANT HAVE EVOLVED IN RESPONSE TO HERBIVORES.
Morphological...THORNS
Associational...GROW NEAR A THORN BUSH
Chemical (secondary compounds)...POT OR ALCOHOL IN SEEDS.
one of the first mathematical models of predator-prey interactions; initially
assumed one predator species and one prey species; based on a set of
differential equations.
Lotka-Volterra predator-prey model
Lotka-Volterra predator-prey model IS BASED ON WHAT?
change in predator numbers over the change in time in relation to changes in prey density over time.
UNDERSTAND THE DIFFERENT TYPES:
CYCLIC CYCLE LIMITS?
2,4,8,16,32,64..
Temporal scale must always be carefully considered when trying to describe cycles (or any other population dynamics).
WHY?
ONE MIGHT NOT COVER THE COMPLETE CYCLE OF THE ORGANISM.
SPRUCE BUDWORM. CAN'T DO A 10 YEAR CHART WHEN IT'S CYCLE IS 25.
DEFINE Functional and numerical responses
Numerical response –
when predator numbers respond to changes in prey numbers, i.e., prey go up,
predators increase; prey go down, predators decrease.
Three types of functional responses:
1. Type I....ZOOPLANKTON
2. Type II....SEEDS...EAT FAST THEN LEVEL OFF
3. Type III...SEARCH IMAGE. IF RARE, LESS LIKELY TO EAT. BUT IF COMMON THEN BECOMES AVERAGE.
DEFINE THE 3 TYPES
1. Type I....ZOOPLANKTON
2. Type II....SEEDS...EAT FAST THEN LEVEL OFF
3. Type III...SEARCH IMAGE. IF RARE, LESS LIKELY TO EAT. BUT IF COMMON THEN BECOMES AVERAGE.
.
Ways in which animals try to reduce predation:
1. Cryptic coloration
2. Aposematic coloration
3. Aggressive resemblance
4. Mimicry
DEFINE Mimicry
is the resemblance of one organism to a not very closely related organism living in the same area.
Two types of mimicry.
1. Batesian mimicry – an edible mimic resembles a distasteful or poisonous model. e.g., viceroy – monarch mimics; fly – bee mimics; king snake – coral snake mimics.
2. Mullerian mimicry – when several poisonous or unpalatable species resemble one another.
2 EXAMPLES OF MULLERIAN MIMICRY.
FROGS IN TROPICS.
BEES/WASPS/FLY IN MIDWEST.
A fly MIMICS A BEE WHAT TYPE IF MIMICRY?
1. Batesian mimicry – an edible mimic resembles a distasteful or poisonous model. e.g., viceroy – monarch
Ectoparasite – parasites that live ontheir hosts, e.g., fleas and ticks.
DEFINE Endoparasite
Endoparasite – parasites that live in their hosts, e.g., viruses, blood flukes, and some tapeworms.
DEFINE Microparasite
Microparasite – comparatively small parasites that generally multiply within their host, e.g., viruses, bacteria, and fungi
DEFINE Macroparasite
Macroparasite – comparatively large parasites that generally do not multiply within the host; produce eggs or larvae that pass out of the host; e.g.,
parasitic worms and arthropods.
DEFINE Parasitoids
Parasitoids – flies or wasps that live as parasites within the egg, larvae, or pupa of another insect, consuming its tissues; eventually they emerge and the host dies.
EXAMPLE OF PRARSITOIDS
PARASITIC WASP INJECTS FLY WITH EGGS.
T OR F?
Animals have been referred to as "plant parasites."
TRUE
WHO IS A HOST/CARRIER OF RIVER BLINDNESS?
RIVER FLY
SAND FLY SPREAD WHAT?
LIECHMANS TYPE OF DISEASE.
NAME THE 2 HOSTS OF SWIMMERS ICH
SNAIL AND DUCK.
WHAT TRASMITTED THE PLAGUE?
TICKS.
RESULTS OF TSETSE FLY BIT.
TRYPANAZOMA.
T OR F ?
Pathogens and parasites can not only
limit population size, but also alter the outcome of interspecific competition
and affect the distribution of species.
TRUE
DEFINE Commensalism
where individuals of one species, the commensal, live off of another species, the host; the commensal benefits and the host suffers no negative or positive effects; e.g., epiphytic plants.
DEFINE Phoresy
the transport of one animal by another.
DEFINE Saprobism
organisms that obtain their energy from dead or dying tissue.
EXAMPLE OF A SAPROBIAN
Saprobism – organisms that obtain their energy from dead or dying tissue.
T OR F?
Resources may never or only rarely be in short supply.
Consequently, competition is of relatively little importance.
TRUE.
Many, possibly most, resources are
used by more than one species. This can result in several possible outcomes.
NAME THE 4 MAJOR OUTCOMES
1. Resources may never or only rarely be in short supply. Consequently, competition is of relatively little importance.
2. Competition between two species may be mild enough that they can coexist.
3. Ghost of competition past: Competition may not be observed between two species, although sometime in the evolutionary past members of the two species were in competition.
4. Competition may result in competitive exclusion.
WHEN RESOURCES ARE USED BY MORE THAN ONE SPECIES, MANY OUTCOMES.
1. RESOURCES MAY NEVER ON RARELY BE IN SHORT SUPPLY.
EXPLAIN 4 POINT IF THIS.
A. The resource may nondepletable, rapidly renewable, or nonmonopolizable.
B. Predators or parasites may depress prey to a level in which interspecific competition does not occur.
C. Annual variability in seasons prevents populations from reaching carrying capacity.
D. Disturbances, such as fires, floods, and ice-storms, prevent populations from reaching carrying capacity.
GIVE EXAMPLE OF APPARENT COMPETITION
CARABO (MAINE) COMPETITOR WITH DEER.
CARABO DEAD, NOT DEER.
PARASITE. BUT LOOKED LIKE DEER.
ANOTHER
LYNX, RABBIT AND HAIRS OF NOVA SCOTIA.
DEFINE interspecific
arising or occurring between species; "an interspecific hybrid".
DEFINE intraspecific competition
:occurring within a species or involving members of one species
T OR F ?
two competing species will be able to coexist if the effects of crowding are more severe intraspecifically than interspecifically.
TRUE
T OR F ?
Refugia can result in coexistence.
TRUE.
DEFINE relict
an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas
DEFINE RUFUGIA
An area that has escaped ecological changes occurring elsewhere and so provides a suitable habitat for relict species.
T OR F?
Directional selection can also help reduce interspecific competition.
TRUE
THINK GHOST COMPETITION.
IS MOST COMPETITION ASYMMETRICAL?
YES.
MICE VS MOLE
If the birth rate or death rate were to change as a population got bigger (or smaller), then they would be said to be density WHAT?
dependent.
DEFINE Amensalism
a coaction in which one species is harmed and the other is unaffected.
DEFINE Allelopathy
Chemical inhibition of one organism by another. Generally used in reference to higher plants.
TREES. WALNUTS. MARIGOLD.
DEFINE Neutralism.
when two species have negligible effects on each other on an ecological time scale. Neutralism may evolve from competition.
GHOST COMPETITION.
DEFINE Mutualism.
the coaction which both species benefit.
EXAMPLE OF SYMBIOTIC MUTALISM
Lichens(algae and fungi) and herbivore / digestive microorganisms.
WHAT IS A Mycorrhizae.
NAME THE 2 TYPES.
fungi that are found in close association with the roots of vascular plants.
