207 Flashcards
Limnology:
Multidisciplinary to the study of all inland water communities, and their interactions with physical, chemical and biological environments
-euphotic zone:
littoral zone (intertidal zone), neritic zone, epipelagic zone
littoral zone (intertidal zone)
shallow shoreline, influence of tides- high productivity gets sufficient light and gets nutrients from ocean and terrestrial run off- waves - most things live in this zone
aphotic zone
reduced -> no light
benthic
bottom sediment
If the conditions exceed the optimum species
ranges, the species may have to:
– Migrate to more suitable locations
– Dormancy
– Adapt/acclimate to changing conditions
Stabilizing selection
- Extreme phenotypes are selected against and average phenotypes are favoured
- Average traits have the best survival
- Eliminates harmful mutations
– Maintains status quo
(no evolution)
natural selection mechanisms
- Stabilizing selection
- Directional selection
- Disruptive selection
Directional selection
- An extreme trait has increased survival, traits move toward the “better” or “most adapted” trait
- New beneficial mutations are fixed in the population
Disruptive selection
- 2 traits have increased fitness, traits move to bimodal
- Or intermediate trait is selected against
- Responsible in part for sympatric speciation
Microevolution
– operates at the population level
– random and selection processes
Macroevolution:
– operates at the species and higher taxonomic levels
– speciation
Species
species:
– Organisms that form a natural
population
– Reproductively isolated
– Will transmit specific characteristics
from parent to offspring
BIOLOGICAL SPECIES CONCEPT (BSC)
– A group of organisms reproductively isolated from
similar organivsms =
* Infertile organisms will arise when different species crossed
ecocline
a gradual change in a genotype or a phenotype of a species over a large geographic area
ecotype
individuals of a species on opposite ends may appear very diff from eachother. if genetically distinct from each other they may be called a subspecies or separate species
Allopatric Speciation
-Geographic isolation,
no movement of population
-Genetic differentiation
Parapatric Speciation
– Movement into a new habitat, no isolation
– New genes dominant and excel in new habitat
– Habitat expansion
– Divergence may occur because of reduced gene flow
Sympatric Speciation
– Genetic drift occurring when populations are free moving with no barriers
– New niche exploited
– Randomly mating species
– may result due to assortative mating
To avoid heating, plants have (3)
options:
- Decrease heating via conduction (Hcd)
- Increase convective cooling (Hcv)
- Reduce radiative heating (Hr)
response to water stress
– Plant stomata are typically more active in cooler, humid part
of the day. (reduction in water loss)
– Alter leaf shape or plant shape (short term vs. evolved)
– Prematurely drop leaves
– Water stress inhibits the production of chlorophyll
– Increase root development
Consequences of water stress
A reduction in the growth rate of the plant with a smaller leaf area
Plants in a high temperature environment must to maintain heat balance by
– Place leaves above the ground to avoid the ground convective heat
– Small leaves to promote convective cooling (and increase air flow to the
stem)
– Hairs on leaves will reflect light
– Leaves will orientate parallel to the sunlight to reduce radiative heat gain
population
is a group of individuals of the same species living in a given area at the
same time.
community
a group of plants and animals interacting in a particular region
microclimate
-microclimate: is a specific habitat (small scale) of an area which may differ from the general climate of the area
-ground colour- darker colours absorb more light
boulders/burrows-create shaded cooler environments
Thermal neutral zone
the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced.
order of indivi
-individuals, population,community, ecosystem, landscape, region, biosphere
law of tolerance
distribution and abundance of species depends on deviation between local conditions and optimal conditions for species
Poikilotherms
Body temperature varies directly
with environmental temperatures.
Homeotherms
– maintain a relatively constant
internal environment.
Ectotherms
– Rely mainly on external energy
Endotherms
– Rely heavily on metabolic energy
Short horned lizard of Alberta
both Poikilotherms and Ectotherms
marine fish
ectotherms that are homeothermic
fitness
Fitness is the quantitative representation of individual reproductive success. It is also equal to the average contribution to the gene pool of the next generation, made by the same individuals of the specified genotype or phenotype.
genetic drift
the change in frequency of an existing gene variant in the population due to random chance.
gene flow
the transfer of genetic material from one population to another. Gene flow can take place between two populations of the same species through migration, and is mediated by reproduction and vertical gene transfer from parent to offspring.
Tundra-
lacking trees because of moisture conditions,less evaporation, sufficient moisture. Soils low decomposition, plants are slow growing, not great diversity but good abundance.
boreal forest/ tiaga
extremely variable in temp- moderate precipitate low evaporation= water accumulation- soil is low fertility thin and acidic, low decomposition
temperate forest
. Temperatures have low variability - heavy precipitation- precipitation heavy in winter, fall and spring . fertile soils
river zones
epilimion- warm, low density
thermocline- zone of rapid temp change
hypolimnion-cold high density
ecosystem ecology
Biological, physical, and chemical processes and interactions.
why high productivity in intertidal
conc of nutrients, force of waves, temp, solar radiation
Earth’s climatic variation is due to
spherical shape of earth, unevening heating of earths surface, earths axial rotation as it orbits
influences of soil structure
age, parent material, climate, organisms
oligotrophic lakes
high oxygen, low nutrients, deep and clear waters, low productivtity
Due to cool temperatures they store oxygen better (look up oxygen storage of water at varying temperatures)
Ectotherms often use ________ strategies to maintain an optimum operative temperature range.
behavioural
genetic diversity
mutations, crossing over, independent assortment, gene flow
- not genetic drift
plants dealing with water stress
closing stomata, developing thick leaves, alternative water conserving pathways for photosynthesis, dropping and wilting leaves
bogs and fens
have low salitity, nutrient limination, water logged soils, anaerobic environments
difference
bogs have low ph
fens can be basic or acidic
An annual plant adapts to cold temperatures by:
completing its life cycle in a single year
ecotypes.
Locally adapted and genetically distinctive populations within a species are referred to as
plant located in an arid climate will possess all of the following in order to prevent water loss
reduced leaf size,
decreased shoot biomass,
increased root length,
waxy coating.
amensalism
one organism isnt effected and the other is negatively effected
most intense competition
closely related species. intra more than inter
gauses (competitive exclusion) principle
-no two species with same niche can coexist. one will outcompete the other. the winner may be random if identical
exploitative or indirect competition
competition to secure resources first.
-consumptive
-premeptive
consumptive
one species overconsumes the food
pre- emptive
occupying an area
exploitative, interference
interference
direct aggressive interaction between individuals
-overgrowth
-chemical interference
-territorial
-encounter
over growth
one species out growing another
chemical interference
use chemical to limit growth
allelopathy-prevent growth, germination
territorial
defence of an area
encounter
direct fighting for a resource
mechanisms of competition
consumption, pre emption, overgrowth, alleopathym,territory,encounter
fundamental niche
realized niche
removal of a competitor results in
increased growth
increased nutrients
expanded range
liebigs law of the minimum
population increases until critical resource is limiting
what is needed for specie to co exist
habitat differences
food differences
different activity time
coexistance may occur if
- resources are not limiting, low competition
2.resource partitioning-species will use differing sizes of prey, different feeding times - species will exploit only a portion of resources unavailable to othersresulting in the coexistance of species
herbivory
exploitative interaction- reduces fitness of plant
consumptive effects
direct effects predators have on prey populations through capture and consummption =death
non consumptive effects
indirect effects - changes in prey as a consequence of predators being present, even when prey arent killed
indirect effects on the behaviour of prey
vigilance, habitat selection, grouping, inducible defenses, fear
assumptions of loltka volterra equations
- in absence of predators, prey grow exponentially (logistically)
2.predator limited only by availability of prey - prey and predator reproduce continuously, have no age structure and are all identical
4.models assume predation is random
5.predator mortality rate is density independant
general outcomes of lv model
-extinction of predator,survival of prey
-exrinction of prey followed by extinction of predator
-oscillations that dampen to stable point
-oscillations that increase until the extinction of one
-immediate stable limit cycle
-immediate stable point
laws of population ecology
-populations tend to grow exponetially
-populations show self limiations
-consumer resource interactions tend to be oscillatory
factors contributing to stable limit cycle
-rarity of prey drives predators down
-predators catch up and reduce prey
-prey not limited(rapid increase)predators not consuming at fmax dont respond
-carrying capacity slows prey
to get oscillations or co existence (My hair and nails)
-multiple predators
-heterogenity
-addition of individuals (immigration)
–non random predation
reality of predation
-predation is not random
-prey have refuges
-predators may have a carrying capacity unrelated to prey
-generation times differ between prey and predator
-predators may be generalists
-multiple equilibria may occur
prey defenses against predators
-chemical
-protective armour
-crypsis - camoflages
-object resemblance
-flashing colour
-behaviour
-aposematism- warning colours
mullerian mimicry
deimatic behaviour
sudden threatening or startling behaviour
batesian mimicry
colours resemble poisonous
lethal
sublethal
plant defenses to grazing
sructural
-thorns, spines, c:n ratio
avoiding predation- refuges
spatial refuge- areas of escape
temporal refuges- alter phenology and growth rate
refuges- body size
large body size
large groups - refuges
trophic cascade
a progression of indirect effects by predators across succesfullu lower trophic levels
location parasites
endoparasite-living within the host
ectoparasite-living on the host
size parasites
micro parasite
macro parasite
host vulnerable to infection
-host immune response
facultative-
mutualism can live without partner
obligate
cannot live without mutualistic partner
non symbiotic
-species do not physically coexist
seed dispersal
for a population to be mutualistic
-fitness of successful mutuals must be greater than either unsucessful or nonmutualists
-combined fitness of successful and unsuccessful mutualists must exceed non mutualistts
index of species abundance
species diversity
richness
number of species in a community
eveness
relative abundance and variation of species in a community. the numerical distribution of species in relation to others.
shannon wiener
combines species richness with the number of individuals per species
alpha
local diversity
beta
change in diverstiy
gamma
regional diversity
shannon weiner index
index maximum when all species equally abundant
factors affecting species diversity
- physical structure reflects abiotic factors - avaliablity of resources
2.species interactions - disturbance
species diversity is higher in more complex environments
diversity increases with hetero
community stratification
increased stratification allows for more species diversity
species zonation
disturbance
any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources , substrate avaliablilty or the pjhysical enviornment
connell
intermediate disturbsnce promote higher diversity
succession
the directional change in the structure of a community through time. each sequence a sere
succession
all in one location; change in time
zonation
change over space/gradient
Characteristics of population distributions
Components to understanding population distributions are:
- Geographic range: where in the world species lives
- Density: how many individuals per area
- Dispersion: spacing of individuals with area
- Dispersal: movement from one area to another
Fundamental niche
Abiotic conditions which species can tolerate
Realized niche
Abiotic & Biotic conditions species tolerates
geographic range
- Determined by the presence or absence of suitable habitat
- Contains the range of ecological conditions needed for survival
- ie. Where is the geographic distribution of the moose (Alces alces) in Alberta? Why?
– What habitat components does the moose require? - Where is the Alberta distribution for the short horned lizard?
Density
Density
Density = The number of individuals (n) in an area of habitat
– Reflects quality of the habitat
* Carrying capacity (K)
* Directly connected to ecological interactions
– i.e. Species are more common where there are more resources
* though may vary over time OR be related to other factors
lowest r wins competition for a single resoiurce
effect of competition
reduced population size, reduced realized niche space
what is needed for species to coexist
habitat differences, food differeences, different activity times
coexistence may occur if
resources are not limitng , resource partitioning
why does predation matter
-affects distribution of prey species
-regulate prey and predator populations
–can force the structure of communities
reality of predation
predation is not random, prey have refuges, predators carrying capacity unrelated to prey,generaation times differ between prey and predator, predators may be generalists
lynx hare cycle conclusions
at high hair density numerical rwesponse oflynx and coyotes decrease= predation
. fear of predation leads to reduced birth rates =predsation
fcators that stabilize predator prey interactions
-interference from outsdie the system (immigration)
-escape from predation, partial prey refuge
mycorrhizae-
feed on plant roots. plants get better nutrients and better extraction of water
how do we determine community structure
types of species, numbers of species, index of relative abundacne
richness
of species]
intermediate disturbance
allows for persistance of species that are good colonizers and species that are good competitors
ecosystem
biotic community and abiotic factors
ecosystems maintain themselves
by cycling energy and nutrients
the low rate of energy transfer between trophic levels
makes decomposers generally more important
primary production
fixation of energy by autotraophs. conversion of inorganic to organic
gross primary production
total energy fixed by autotrophs
net primary production
energy left over by autotrophs after meeting metabolic and energic needs
terrestrial primary prdoctuivity
temperature and moisture
areas near equator have the highest
productivity
aquatic primary production
nutrient limited
two laws of thermodynamics
1.total amount of energy is constant. not created or destoryed
2.heat energy will move from warm to cold. entropy will tend to increase in a closed system
what limits energy transfer
respiration, growth and reproduction.
energy loss to heat
importance of food webs
strength of interactions determine impact on entire foodweb
guild
group of organisms that make their living in a similar way
keystone species
-a species that has a disporportionate impact on the community relative to its abundance
removal of keystone
loss of diverstiy,
cascading events may occur
deep roots in fry environments
water conservation of species
- Behavioural
– Restrict daily activities to cooler parts of the day
– Burrows or utilize other cooler microclimates
– Seasonal migration - Physiological
– Raised body temperature (Camel 42C without sweating)
– Reduce metabolism
– More efficient large intestine reabsorbs water - Morphological
– Enlarged nasal passages to condense water as it leaves via
water vapour
– skin water-proofing, fur, feathers
Water and Salt Balance
- If they have excess salts
– Elimination in urine
–Drink larger volume of water
– If water is limiting
→ must concentrate urine - Kangaroo Rat (14 X more
concentrated than human) - Special adapted kidney
– Larger medulla region
– Greater length of the loop of Henle
Foraging theory
- The rates at which organisms can take in energy and nutrients are limited
- Even when presented with the opportunity for unlimited intake (unlimited supply of resources), an organisms’ actual rate of intake is limited by physical & physiological means
- Limitations on consumption are common to all species
Type 1:
Feeding rate increases linearly as food density increases — levels off at a maximum.
* consumers require little or no search and handling time.
* i.e. filter feeders
Type 2:
Feeding rate rises in proportion to food density
– Feeding rate partially limited by search/handling time.
– At low food densities, limited by difficulty in finding food
– As prey increase, easier to find
– Handling time is constant but limits feeding at intermediate densities
Handling includes: cracking shells, seeds, chasing elusive prey and digesting prey
type 3
: Feeding rate increases most rapidly at intermediate densities
(S-shaped).
– Prey protected at low densities
– Habitat protecting prey
– Predators will switch to different
prey at low densities
– Predators need to learn how to find,
catch and kill prey
Optimal Foraging Theory
= Tendency of animals to harvest food efficiently
– selecting food sizes or food patches that supply maximum food intake for energy expended.
* Search for prey
* Handling time
* Tend to maximize rate of energy intake.
Expect natural selection to favour individuals that are more effective at acquiring limiting resources
prfotiability
abundance, energy gained, handling time, cost of searching
Marginal Value Theorem (Charnov 1976)
= Tendency of animals to harvest food efficiently
– selecting food sizes or food patches that supply maximum food intake for energy expended.
* Search for prey
* Handling time
* Tend to maximize rate of energy intake.
Expect natural selection to favour individuals that are more effective at acquiring limiting resources
- Predicts that animal should stay in patch longer if
- time to reach new patch is high,
- if general environment is low in food,
- or if current patch is especially high in food.
Sexual Dimorphism arises when:
- Different functions result in male/female
differences.
ie. Females produce larger gamete than males, results in:
Larger sized females - There is intense competition between males
for females
Results may include: head ornaments - Females may choose males with the best
display, colour, song, etc
\
key life history traits
body size, fecundity,parity,maturity,parental care, life expectancy
fecundity
of offspring
parity-
of reproduction times
maturity
age of 1st reprod
How to maximize fitness?
- How often should they breed?
* Trade-off between fecundity and survival - How many offspring should they produce in each event?
* Trade-off between fecundity and survival - When should they produce offspring?
* Trade-off between breeding earlier and not living longer or breeding later
and living longer (and growth)
Semelparous
one main repro event
Iteroparous
multiple repro events
Fecundity trend
larger clutches with an increase in latitude.
* Conclusions:
– Increased litter sizes with latitude
– Reflects the largest # of offspring
parents can feed.
– Light increases with latitude in the
summer
Altricial
heavy investment
* Young born helpless
* (ie. Blind and naked)
precocial
light investment
* Partial development
* (ie. Move shortly after birth)
grime
disturbance, abiotic stress, competition
Plant Life Histories
*Ruderals (highly disturbed habitats)
* Grow rapidly and produce seeds quickly.
*Stress-Tolerant (high stress—no disturbance)
* Grow slowly—conserve resources.
*Competitive (low disturbance, low stress)
* Grow well, but eventually compete with others for resources.
oppurtunistic graph
low survival ship, low fecundy, earlyage of repro mature
equilibrium
high suvrvial, low fecudnity, late mature
periodic
low survival, high fecundity, late matutre
inclusive fitness
the survival and reproduction of an individual plus the survival and reproduction of individuals with whom it shares genes
Grime’s classification of plant life histories focuses attention on
stress and disturbance
