Ecology Exam 2

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Water will always move _______ concentration gradients

magnitude gradients

Determines if organism loses or gains H2O from environment

evaporation

Accounts for much of water lost by terrestrial organisms

Relative humidity equation

Relative humidity= (water vapor density/saturation water vapor density)*100

Water vapor density measurement

measured as the water vapor per unit volume of air

saturation water vapor density measurement

measured as quantity of water vapor air can potentially hold, changes with temperature

Total atmospheric pressure

pressure exerted by all gases in the air

Water vapor pressure

partial pressure due to water vapor

Saturation water vapor pressure

pressure exerted by water vapor in air saturated by water

Vapor pressure deficit

difference between WVP and SWVP at a particular temperature

Higher vapor pressure deficit causes ____________ rate of evaporation

higher

Is water more concentrated in freshwater environments or in the oceans?

freshwater environments

osmosis

diffusion across a semipermeable membrane

Isosmotic (isoosmotic)

body fluids in organism and external fluid are at the same concentration

Hypoosmotic

body fluids are at higher water concentration than external environment

Hyperosmotic

body fluids are at a lower water concentration than external environment

Water potential (psi)

capacity of water to perform work, generally negative in nature, water potential of the solute measures the reduction in water potential due to dissolved substances

0

water potential of pure water

Matric forces

waters tendency to adhere to container walls

Ψ_pressure

reduction in water potential due to negative pressure created by water evaporating from leaves

2 major challenges terrestrial organisms face

-evaporative loss to environment

-limited access to replacement water

Metabolic water

the water released during cellular respiration

What will a plant allocate resources to?

the structure or function responsible to the acquisition of resources that are most limiting

water conservation by plants and animals

•Many terrestrial organisms equipped with waterproof outer covering.

•Concentrated urine / feces.

•Behavioral adaptations to avoid stress times.

•Drop leaves in response to drought.

•Thick leaves

•Few stomata

Periodic dormancy

Autotrophs

use inorganic source of C and energy

Photosynthetic autotrophs

use CO2 as C source and sunlight as energy

Chemosynthetic autotrophs

use inorganic molecules as source of C and energy

photon flux density

number of photons striking surface area

What factors influence the distribution of light quality/quantity across the earths surface?

*water depth

*water quality

*elevation

*shade

*atmosphere quality

*aspect

*burrows and rocks

Albedo

reflectivity of surfaces (such as soil)

Where do plants get their carbon?

from the atmosphere

How does carbon enter the plant?

CO2 enters the stomata of plants

C3 photosynthesis

named after PGA (3 carbon acid-3-phosphoglycerate), used by most plants and algae

Rubisco

the most abundant enzyme on earth, needs lots of CO2, the enzyme that catalyzes CO2 fixation (low affinity for CO2), catalyzes photorespiration

Photorespiration

O2 + RuBP

occurs in the light

consumes energy

C4 photosynthesis

4 carbon acid produced, PEP carboxylase (enzyme), acids produced during carbon fixation go to specialized cells called bundle sheath, there C3 pathway ensues

CAM photosynthesis

limited to succulent plants in arid and semi-arid environments, carbon fixation takes place at night, reduced water loss, low rates of photosynthesis, extremely high rates of water use efficiency

Denitrifiers

convert nitrate to dinitrogen gas (which can be used by organisms), need NO3

herbivores

mostly feed on plants

carnivores

mostly feed on animal flesh

detritivores

mostly feed on non-living organic matter

What 5 elements make up 93-97% of biomass of plants, animals, fungi, and bacteria

C, O, H, N, P

N and P are usually the hardest to get

How is food quality measured

C:N ratios

Plant defense mechanisms

*thorns/spines

*grow tall

*enlist the help of other organisms for protection

*cellulose

*lignin

*silica

*toxins

*digestion reducing compounds

Organisms prefer eating things with _____ C:N ratios

lower

What constitutes most of the biomass on earth?

plants

How do animal prey not get eaten?

*poison

*venom

*camouflage

*hard outer shells

*detaching limbs

*run fast

*climb well

*nocturnal

*spines

*stay in groups

*emitting odor

*Aposematic coloring

*Mullerian mimicry

*Batesian mimicry

Aposematic coloring

warning colors

Mullerian mimicry

co-mimicry among several spp. of noxious organisms

Batesian mimicry

harmless spp. mimic noxious spp.

Predators

selection agents for refined prey defense

Evolutionary arms race

predator and prey race to evolve to determine the fate of the ecology of the species

Rate of photosynthesis increase with ________

photon flux density

Photosynthetic response curves

increase and then level off at a maximum photosynthesis rate

3 basic functional responses

-feeding rate increases linearly as food density increases then levels off (consumers require little or no search and no handling time)

-feeding rate rises in proportion to food density (feeding rate partially limited by search/handling time), most common

-slow at first then rate increases most rapidly at intermediate densities (s-shaped) (organism learns how to eat diet item more efficiently)

Optimal foraging theory

organisms often have options/choices regarding what they feed on, prey selection maximizes energy intake rate

optimal foraging theory equation

E/T=N_e1E₁-C_s/1+ (N_e1H₁₎

E=Energy

T=Time

N_e1=Number of diet item 1

C_s=Cost of searching H₁

H₁=Handling time

Behavioral Ecology

Interactions btwn. organisms and environment mediated by behavior

Sociobiology

examines social behavior especially as it relates to how behavior relates to fitness

Female

produces larger, more energetically costly gametes

Males

Produce smaller, less energetically costly gametes

Resource access

what limits reproduction

mate access

what limits male reproduction

sexual selection

differences in reproductive rates in individuals as a result of differences in mating success

Intrasexual Selection

individuals of one sex compete among themselves for mates (ex. elk fighting)

Intersexual selection

individuals of one sex choose mates among members of opposite sex (ex. lyre bird dancing)

genetic variation

what evolution acts on

sociality

degree to which individuals in a population associate in social groups

*cooperative feeding

*defense of the social group

*restricted reproductive opportunities

evolution of sociality is generally accompanied by:

eusociality

more complex level of sociality

*individuals of >1 generation living together

*cooperative care of young

*division of individuals into non-reproductive and reproductive castes

characteristics of eusociality

*inclusive fitness

*inherited territory

*kin selection

benefits of cooperative breeding

inclusive fitness

improve survival and reproductive rates of family members

kin selection

evolutionary strategy that favors the reproductive success of an organisms relatives even at cost to its own survival and reproduction

Hamilton’s rule

selection will favor diverting resources to kin when benefits to the helper exceed costs

Hamilton’s rule equation

R_gB - C > 0

R_g=degree of relatedness

B=reproductive benefit gained by the recipient of the help.

C=costs

population

group of individuals of a single species inhabiting a specific area, characterized by the # of individuals and their density

number of individuals, density, age distributions, growth rates, distribution, and abundance

characteristics of a population

niche

summary of factors that influence growth, survival, and reproduction of a species

niche- hutchinsons definition

n-dimensional hyper-volume

n equates to # of environmental factors important to survival and reproduction of a species. volume=range

fundamental niche

hypervolume (abiotic factors)

realized niche

biotic interactions such as competition or symbioses that may restrict or expand environments where species may live

food production; water supply; habitat; incidence of parasites, pathogens, and competitors; human impacts

climate often influences species distributions via

random distribution

equal chance of being anywhere, uniform distribution of resources

regular distribution

uniformly spaced, exclusive use of areas, individuals avoid one another

clumped distribution

unequal chance of being anywhere, mutual attraction between individuals, patchy resource distribution

rarity I

extensive range, broad habitat tolerance, small local populations (ex. peregrine falcon)

rarity II

extensive range, large populations, narrow habitat tolerance (ex. passenger pigeon)

rarity III

restricted range, narrow habitat tolerance, small populations (California condor)

metapopulations

groups of subpopulations living on patches of habitat connected by an exchange of individuals

cohort life table, static life table, age distribution

3 main methods of estimation

cohort life table

identify individuals born at same time and keep records from birth (best, but difficult)

static life table

record age-at-death of individuals

age distribution

calculate difference in proportion of individuals in each age class, assumes difference from mortality

Type I survivorship curve

majority of mortality occurs among older individuals (ex. dall sheep)

Type II survivorship curve

constant rate of survival throughout lifetime (ex. american robins and mud turtles)

Type III survivorship curves

high mortality among young, followed by high survivorship (ex. perennial shrub)

anticipate future populations, identify the drivers of population growth, manage populations of conservation concern, evaluate interactions among species

modeling population growth used to:

generations do not overlap

growth can be modeled geometrically when

Geometric growth equation

N_t = N_oλ^t

N_t = Number of individuals at time t.

N_o = Initial number of individuals.

λ = Geometric rate of increase. (# offspring left by individual in 1 time interval)

t = Number of time intervals or generations.