Biology 171 Exam 2 Andrew

Front 1

Pleiotropy

Back 1

One gene affects many traits

Front 2

Polygenic Inheritance

Back 2

Many genes affect one trait

Front 3

Disruptive Selection

Back 3

Intermediate traits are not favored, but extremes are. The result is that the distribution of the phenotype becomes bimodal.

Front 4

Stabilizing Selection

Back 4

The extremes are not favored, so the distribution of phenotypes collect towards the intermediate

Front 5

Tetrad

Back 5

Two replicated chromosomes combined

Front 6

Balancing Selection

Back 6

Heterozygote genotypes are favored over homozygotes

Front 7

Directional Selection

Back 7

One tail of the phenotypic distribution is favored. The "standard deviation" is also reduced in Directional Selection.

Front 8

GPP

Back 8

The total amount of photosynthesis occurring per unit area

Front 9

NPP

Back 9

The amount of chemical energy produced minus the energy used for cellular respiration

Front 10

Linneaus

Back 10

Developeda nested classification of species by grouping species by morphological similarities

Front 11

Hutton

Back 11

The idea that small changes occurring over long periods of time can accumulate to cause large transformations of the Earth

Front 12

Lamarck

Back 12

Promoted the idea that species change over time

Front 13

Malthus

Back 13

Populations have the potential to grow exponentially and will therefore compete for resources

Front 14

Cuvier

Back 14

Showed that extinctions were common. Also believed in Catastrophism (?)

Front 15

Lyell

Back 15

Uniforitarianism - the idea that geological mechanisms that operated durin the Earth's history continued to operate today and at the same rate

Front 16

What is the Hardy-Weinberg Principle?

Back 16

1 = p^2 +2pq + q^2

Front 17

If a population is _______ evolving, then genotype and allele frequencies in the population will be STABLE

Back 17

Not

Front 18

What are the requirements for the Hardy-Weinberg Equilibrium?

Back 18

Population size is very large
Population is close (no gene flow)
No mutations are occurring at gene under study
Mating is random with respect to trait under study (no sexual selection, no inbreeding at gene under study)
All genotypes in population have equal chance of surviving and reproducing

Front 19

Sexual Selection

Back 19

Process by which individuals that possess certain heritable traits are more successful at obtaining mates and thus reproduce at a higher rate than individuals that lack those traits

Front 20

What are humans doing to change the carbon cycle?

Back 20

We add CO2 via intensive agriculture, deforestation, and the burning of fossil fuels

Front 21

What are humans doing to change the Water Cycle?

Back 21

We have concrete, we cut down forests which increases runoff, we irrigate agricultural fields, and we have to mine for water

Front 22

What are humans doing to change the Nitrogen Cycle?

Back 22

We burn fossil fuels (releasing N20), we use fertilizers, and we cultivate certain crops that have a major impact on the global cycle

Front 23

What are some advantages and disadvantages of asexual reproduction?

Back 23

Advantages: you dont need a mate, or expend energy to attract a mate, there are fewer risks of STDs, and it leads to faster population increases
Disadvantages: little genetic variation for evolution to act upon, no way to get rid of deleterious mutations

Front 24

When does crossing over occur?

Back 24

Prophase 1

Front 25

Mendel's Law of Segregation

Back 25

Alleles separate during gamete formation and each gamete receives only one allele for each trait

Front 26

What is Mendel's Law of Independent Assortment?

Back 26

It is the concept that alleles of different genes are transmitted independently of one another

Front 27

T.H. Morgan

Back 27

Discovered Sex-Linkage with fruit flys

Front 28

Why do we use fruit flies in the lab? (or peas, for that matter)

Back 28

Small size and easy to culture, short generation time, produces 100s of offspring per mating

Front 29

The lower the % recombination, then the _____ the two genes are

Back 29

Closer

Front 30

Codominance

Back 30

When both alleles are expressed simultaneously

Front 31

Incomplete Dominance

Back 31

Phenotype of a heterozygote is intermediate to the two homozygotes

Front 32

Epistasis

Back 32

One gene alters the expression of another gene (genes interact)

Front 33

What is chemosynthesis?

Back 33

The process by which bacteria and archaea use H2S and other inorganic molecules as an energy source

Front 34

Terrestrial Primary Productivity ________ from the equator towards the poles

Back 34

Declines

Front 35

What limits primary production in aquatic ecosystems?

Back 35

Nutrients and light

Front 36

What is phytodetritus?

Back 36

It is organic material that sinks rapidly from surface waters to deep communities (a phenomenon called marine snow)

Front 37

First Law of Thermodynamics

Back 37

Energy is neither created nor destroyed, but it can be transferred from one body/form to another

Front 38

Second Law of Thermodynamics

Back 38

Energy transfer leads towards entropy

Front 39

Cellular Respiration uses ________ and produces ___________

Back 39

Sugar and O2, and ATP, CO2, H2O, and heat

Front 40

Photosynthesis uses _______ and produces _______

Back 40

light energy, CO2, and H20
Sugar and O2

Front 41

Why do plants need to carry out both photosynthesis and cellular respiration?

Back 41

Photosynthesis only makes glucose; they need cellular respiration to access the energy

Front 42

Secondary Production

Back 42

The amount of new tissue produced by consumers from the foods they ingest

Front 43

What are the reasons for the pyramid of productivity?

Back 43

A large fraction of energy is released as heat within each trophic transfer.
A large fraction of the energy present at each level is used to keep the organisms alive.
Not all organisms at lower trophic levels are consumed.

Front 44

Where does most of a plants mass come from?

Back 44

Carbon Dioxide

Front 45

What are the Limiting Nutrients?

Back 45

Nitrogen, Phosphorus, and Potassium

Front 46

Detritus

Back 46

Materials that have organic molecules that must be broken down by decomposers

Front 47

The decomposition of detritus limits the rate at which nutrients move through an ecosystem?

Back 47

True

Front 48

What are two abiotic factors that influence decomposition rate?

Back 48

Warm temperatures and moist soils

Front 49

Plants need nitrogen in a ______ form.

Back 49

Fixed

Front 50

What are some GHG's?

Back 50

Water vapor, CO2, ozone, methane, benzene, N20

Front 51

Albedo

Back 51

The fraction of radiation striking a surface that is reflected by that surface

Front 52

How do meiosis and sex generate genetic variation?

Back 52

Crossing over and independent assortment of homologs and RANDOM fertilization of gametes

Front 53

Anisogamy

Back 53

Defined by the occurrence of gametes of different sizes

Front 54

Bateman and Trivers' Principles:

Back 54

Male fitness will be limited by the number of mates, whereas female fitness will not.
Because females invest more in each gamete, they invest more in parental care of an offspring.
Females should be choosier about who they mate with, and males compete more for mates.

Front 55

Sexual Dimorphism

Back 55

Difference between the sexes in traits related to attracting and obtaining mates

Front 56

Intrasexual Selection

Back 56

Competition within a sex

Front 57

Intersexual Selection

Back 57

Female mate choice selects for male reproductive traits

Front 58

What are some examples of Male-Male Competition?

Back 58

Male combat, ritualized displays, and sperm competition

Front 59

Cryptic female choice?

Back 59

Females are NOT picky about who they mate with, but after mating, females control which sperm fertilize their eggs

Front 60

Direct vs. Indirect Benefits

Back 60

Males offer resources in addition to sperm, vs. males offer only sperm

Front 61

Good Genes Model

Back 61

Females choose mates whose genes improve their offspring's survival and reproduction

Front 62

"Sexy Sons"

Back 62

Female preferences can initially be arbitrary, but as females choose mates with certain traits, both the male trait and the female preference co-evolve.

Front 63

What is a genetic bottleneck?

Back 63

It's a sudden reduction in the number of alleles in a population.

Front 64

What is the founder effect?

Back 64

It's when the introduction of a new population results in a change in allele frequencies.

Front 65

What is genetic drift?

Back 65

It's defined as any change in allele frequencies in a population that is due to chance.

Front 66

What are the three key points about genetic drift?

Back 66

It is random with respect to fitness.
It is most pronounced in small populations.
Over time, it can lead to the random loss or fixation of alleles.

Front 67

What is gene flow?

Back 67

It is the movement of alleles from one population to another. It occurs when individuals leave one population, join another, and breed.

Front 68

Is evolution goal directed or not?

Back 68

No! It's not! Adaptations do not occur because organisms want or need them.

Front 69

What is Synapsis?

Back 69

It's when homologous chromosome pairs come together. This happens during early prophase 1.