Prelim #1 Flashcards
Population
Group of individuals of a single species that live in a particular area and interact with on another
community
an association of interacting populations of different species that live in the same area
ecosystem
a community of organism plus the physical environment in which they live
biosphere
all living organisms on earth plus the environments in which they live
Observational Studies: Pros vs Cons
(measure existing patterns, associations between variables of interest)
pros: realism; generate hypothesis
cons: hard to isolate cause and effect
Controlled Experiments:
Pros vs. Cons
(manipulate variables of interest, compare response to control)
pro: isolates cause and effect
con: often less realistic conditions
Take-away from oaks to Lyme disease case study
higher acorn production increases mammal foraging, which leads to high tick populations, increasing Lyme disease risk to humans (more acorns due to less moths which are result of mice)
Evolution: Who has the highest fitness?
person with most offspring…fitness measured by reproductive success
What are the three assertions for evolution by natural selection (excess of individuals, intraspecific competition)?
- variation in phenotypes
- heritability of phenotypes
- phenotype correlated with fitness
Phenotype is function of genetics and the environment (equation)
P=G+E+(GxE)
Macroevolution
over time, we can get very large changes in populations of organisms…if 2 populations are genetically isolated and change enough (so that they can’t reproduce together) they are different species
Microevolution
small scale changes
spatial variation
variation from place to place (at one time)
temporal variation
variation from time to time (at one place)
thermoregulation equation
HNET=HAR- HRR+/- HCOND+/-HCONV - HEVAP+ HMET
Homeotherms
maintain constant temperature
Poikilotherms
body temperature subject to the environment
ectotherms
depend largely on external sources of heat
endotherms
regulate their body temperature by producing heat
Bergmann’s rule
within a broadly distributed genus, larger species are found in colder climates and smaller species are found in warmer regions
As edge/diam increases…
SA/Volume decreases
What about limbs and appendages?
less/smaller appendages will have lower sa:vol…greatest heat loss will be from shape with lots of SA:VOL
As ratio of red: far red decreases, stem elongation….because….
increase because plants think that there is competition for light
where are plant’s eyes? how do we know?
stem; experiment that blinded stem had no shade response (stem elongation) compared to control
first law of thermodynamics
energy is not created nor destroyed by normal chemical means
second law of thermodynamics
when energy is transferred or transformed, part of the energy is lost as heat
Photosynthesis inputs/outputs
inputs: co2, h2o, light
outputs: glucose, oxygen
respiration inputs/outputs
inputs: o2, glucose
outputs: co2, ATP, water
C3 photosynthesis
most common photosynthesis pathway
C4 photosynthesis
plants in hot areas: more efficient CO2 uptake…occurs in different compartments
CAM photosynthesis
plants in hot/dry areas, often succulents…uncoupled processes in plants. open stomates at night when it is cool, get CO2, trap it
net primary production (NPP)
the total amount of organic matter available for consumption by higher trophic levels
Consumption efficiency
% of NPP consumed
assimilation efficiency
% of ingested food assimilated by an organism
production efficiency
% of assimilated mass that becomes new biomass
trophic efficiency
% of energy from one trophic level acquired by trophic level above and incorporated into biomass (about ~10%)
Geometric growth equation and assumptions
N at time t=lambda^t X N initial
discrete generations, no immigration/emigration, unlimited resources
Equation for rate of change in population size when a population is growing exponentially
dN/dt=rN
r=growth rate
N=number of individuals in population
Exponential growth equation and assumptions
N at time t=e ^(rt) x N initial
no immigration/emiigration, unlimited resources, population does not need to reproduce at same time
if b>d
r>0, population increases , dN/dt>0
if b
r<0, population decreases, dN/dt<0
if b=d
r=0, population size constant, dN/dt=0
logistic growth equation
dN/dt=rmax * N * (1 - (N/K)
population growth rate=intrinsic growth rate as N close to 0 * population size x reduction in growth rate due to crowding
when is most rapid growth?
half the carrying capacity (K/2)
R-selection
abundant resources, density-independent mortality, unpredictable physical environment, (insects and opportunist plants)
K-selection
limiting resources, density-dependent environment, predictable physical environmental (many large mammals)
type 1 survivorship
species that exhibit high survivorship when young and middle aged but high mortality in old age: k-selected (humans, elephants, sheep)
type 2 survivorship
species with relatively constant survival at all ages (ex: birds)
type 3 survivorship
species that exhibit high mortality when young and high survivorship when older (ex: fish, desert shrub)
Life table: x
life stage or age range
life table: Nx
number of individuals at the start of each age
life table: Lx
proportion surviving
life table: Mx
per-female rate of offspring production
R0 definition and equation
summation of Lx*Mx
per-generation rate of increase in the population
semelparity:
occurs when organisms reproduce once and then die…best when environment is stable
iteroparity
occurs when organisms reproduce multiple times over their lifespan
bet-hedging
when organisms suffer decreased fitness in their typical conditions in exchange from increased fitness in stressful conditions (spreading risk)
how do organisms deal with environmental variation? 3 options:
reproduce multiple times, disperse to many different habitat patches, seed, cyst, or egg dormancy to survive harsh times
source sub-populations
b»d produce lots of dispersing indviduals
sink sub-populations
b<
