EES 152: Ecology Exam 2

blue

Within PAR. what color light is used most by photosynthesis?

45%

What percentage does PAR make up of all solar radiation?

photon flux density

What is PAR measured in?

ATP and NADPH

energy from these two molecules is used to build organic molecules, using CO2 as a carbon source

carbon fixation

the process in which inorganic carbon, usually in the form of CO2, is converted into organic molecules, including carbohydrates

C3, C4, and CAM

What are the three ways photosynthesis is done?

mesophyll cells 

Where do all C3 reactions take place?

rubisco

In C3 plants, what enzyme is used to initially fix CO2?

open; large

Do C3 plants need to keep their stomata open or closed? Do they have a small or large amount of stomata?

mesophyll and bundle sheath cells

What two different cells are involved or related to C4 plants?

pepco

In C4 plants, what enzyme is used to initially fix CO2?

less

Compared to C3 plants, do more or less stomata need to be open to bring in the same number of CO2 molecules in C4 plants?

lacking in C3 plants; present in C4 plants

Do the bundle sheath cells in C3 plants have chloroplasts? What about in C4 plants?

CAM plants

plants where stomata close during the day and open at night

lower temperatures reduce the vapor pressure deficit

Why do CAM plants fix carbon at night?

mesophyll, PEP

All reactions in CAM plants occur in ______ cells, like C3 plants, but CO2 is combined initially with _______, like C4.

large vacuoles in mesophyll cells

CAM plant leaves have what?

pepco

In CAM plants, what enzyme is used to initially fix CO2?

C3 plants are more competitive; C4 inefficient at low light intensities, ineffective as shade plants, takes more energy

Why aren’t C4 plants more abundant than C3 plants?

shaded regions: C4 does poorly (less light); C3 does well; opposite for sunny habitats

Plants that occur in shaded habitats versus a plant that occurs in open, sunny habitats. Difference between a C4 and C3 species in these conditions?

the rate is limited

The rate at which photosynthetic organisms can take in energy always levels off with increasing light. What does this mean?

true

TRUE OR FALSE: The current rise in CO2 has potential direct effects on energy acquisition and nutrients

heterotrophs

organisms that obtain their energy by capturing organic molecules manufactured by other organisms

93-97%

How much of biomass is made up of CHONP?

nitrogen

Which nutrient is particularly limiting?

carbon

What other element do ecologists use in ratio with nitrogen?

food

C:N ratio describes the quality of what to consumers?

describes quality of food (plants have high C:N; animals, fungi, bacteria have low C:N)

herbivores need to eat more plants to get enough N and energy; N is used to make DNA, RNA, proteins

Why does the C:N ratio of a food source matter?

toxins and chemical defenses (in tropical plants: mustard oil, capsaicin), symbiosis with ants and trees

What adaptaions have plants developed in response to herbivory?

cellulose; it is not digestible by any animal

What defense do ALL plants have against herbivores, and why?

nitrification

the oxidation of ammonia (NH4) to nitrite (NO2-) to nitrate (NO3-)

camouflage, spines and shells, repellents and poisons, behavior

What defenses have prey evolved in response to predation?

Mullerian mimicry

two or more toxic or harmful species evolve to resemble each other’s warning signals, such as the same pattern or bright colors

Batesian mimicry

a harmless species resembles a harmful one

type I functional response

feeding increases linearly with food supply up to a point and then levels off abruptly; only animals that need little to no time to process food

type II functional response

feeding increases linearly at low densities, rises more slowly at intermediate densities, and then levels off at high densities

time spent finding food

At low food density, feeding rate is limited by what?

time spent finding and handling food

At mid-food-density, feeding rate is limited by what?

time spent handling food

At high food denisty, feeding rate is limited by what?

type III functional response

S-shaped curve; low densities may afford prey more protected hiding spaces

type II

What type functional response is most common?

optimal foraging theory

an ecological concept that predicts animals will evolve behaviors to maximize their fitness by optimizing their foraging decisions, such as maximizing net energy gain or efficiency

principle of allocation

a principle that states an organism has a limited quantity of resources that it can use for life processes

greater energy expenditure

High mortality rate; reproduction at earlier age. What does this mean in terms of energy expenditure?

polygamy

meaning having many mates

polyandry

one female to several mates

polygyny

one male to several females

fecundity

the number of eggs produced per female (physical ability)

distinct differences that results due to competition for mates

Define sexual selection.

intrasexual selection

individuals of one sex compete among themselves for mates (larger size, teeth, antlers) 

intersexual selection

members of one sex consistently choose mates on the basis of a particular trait

elaborate, sexually selected displays or adornments act as handicaps that demonstrate high fitness of the individual (a sign of health that is difficult for a male to fake)

Define the handicap hypothesis

individuals in a group usually spend less time looking for predators, but more time moving to find food

What are the advantages of group living and cooperation? Disadvantages?

inclusive fitness

an organism’s overall fitness determined by its own reproductive success PLUS the reproduction of the individuals which it shares genes with

kin selection

under certain conditions, an organism can increase its inclusive fitness by helping its relatives, which it shares its genes with

age at maturity

age at first reproduction

parity

number of reproductive events 

principle of allocation

if organisms use energy for one function such as growth, the amount of energy available for other functions is reduced

trade-offs between functions such as number and size of offspring

What does the principle of allocation lead to?

areas of high disturbance

Small plants producing large number of small seeds appear to have an advantage in what areas?

surviving environmental hazards

Plants producing large seeds are constrained to producing fewer seedlings, but are more capable of what?

semelparous

organisms that breed only once during their lifetime; allocate stored resources to reproduction, then die

iteroparous

organisms that breed multiple times during their lfiespan

r-selection

rapid development, early reproduction; semelparity, small body size, many small offspring

k-selection

slow development, late reproduction; iteroparity, large body size; few, large offspring

intensity of disturbance (process limiting plants by destroying biomass); intensity of stress (external constraints limiting rate of growth 

What variables are important in Grime’s life history classification of plants?

low disturbance; high stress

stress tolerators

deserts, tundra, alpine meadows, bogs; grow slowly

Where do stress tolerators grow? How do they grow?

low disturbance; low stress

competitors

rapidly; compete with others for resources

How do competitors grow?

high disturbance; low stress

ruderals

colonize disturbed habitats; rapid growth; early maturation and easily dispersed seeds

How do ruderals grow?

metapopulation

a group of subpopulations living on separate patches connected by the exchange of individuals or genetic flow 

N=nM/x (where M is individuals in the initial sample, n is the individuals in the second sample, and x is the number of MARKED individuals in the second sample)

What is the formula for population size given the mark and recapture method?

declines

Population density (declines or increases) with increasing organisms size?

type I survivorship curve

low mortality among young but high mortality among older individuals

type II survivorship curve

fairly constant probability of mortality throughout life

type III survivorship curve 

high mortality among young but low mortality among older individuals

dispersion

describes the spacing of individuals within a population with respect to one another

even spacing

type of spacing that may arise from direct interactions among individuals; direct competition

clumped distribution

type of spacing that may arise from tendency of progeny to remain near parents or clumped distribution of resources; individuals in discrete groups

random distribution

type of spacing that may arise from neutral interactions between individuals and the local environment

males are subject to sexual selection and they aim for those traits to evolve

Why do males tend to get colorful or extravagant in their morphology?