Bio 1780 Prelim 2 Review

Question 1

Is the gametophyte or sporophyte more dominant in mosses? and ferns?

Answer 1

moss: gametophyte, ferns: sporophyte

Question 2

What is found in fungi cell walls?

Answer 2

chitin

Question 3

Why are red algae red? Does it mean they don’t have chloroplast?

Answer 3

They have an accessory pigment phycoerythrin, they have chloroplasts with chlorophyll-a

Question 4

What is found in the cell wall of glaucophyte chloroplasts and what is its significance?

Answer 4

and what is its significance?

a. Peptidoglycan, evidence of endosymbiosis of cyanobacteria

Question 5

How do fungi acquire nutrients? explain the process

Answer 5

Absorptive heterotrophy: hyphae secrete digestive enzymes and processed nutrients are then absorbed

Question 6

What are some problems land plants had to overcome and what structures did they develop to overcome
them?

Answer 6

support - sprawl on ground or have trunk; avoid dessication - stomata; access to water - vascular systems; spreading gametes - shape of seeds

Question 7

What is lichen?

Answer 7

symbiotic relationship b/w fungi (usually ascomycetes) and a photosynthetic partner (either cyanobacteria or
green algae)

Question 8

What is the fitness of an individual measured as?

Answer 8

The number of offspring it produces in its lifetime compared to the average individual in its population

Question 9

What is Hardy-Weinberg equilibrium? What is the formula and what do we use it for?

Answer 9

p
2
+ 2pq + q2
= 1, p + q = 1. Used as null model if no evolution is present

Question 10

Define the Bottleneck effect and predict its outcome

Answer 10

Sudden external factor (e.g. natural disaster) that kills most of the individuals in a population, only leaving a
randomly selected small group of individuals. Genetic drift will cause it to evolve from the previous genotypic
frequencies

Question 11

What does Heterozygosity depend on? How do they each affect the degree of heterozygosity?

Answer 11

Mutation & population size. Increase in both mutation rate and population size will increase heterozygosity

Question 12

For what reason might an advantageous allele have trouble coming to a “fixed” frequency in a population?
What conditions would cause it to do so quickly and easily?

Answer 12

recessive allele advantage = hard to fix b/c hard to get enough homozygous recessive to show effect, dominant
allele fix quickly b/c it’s effect is not shielded

Question 13

What is genetic drift? When is it more important?

Answer 13

chance deviations in allele frequency over time resulting in evolution but without natural selection or adaptation; small populations

Question 14

Why do advantageous alleles that are co-dominant fix faster than those that are dominant?

Answer 14

heterozygous individuals have distinct phenotypes and so its recessive alleles can be selected against more
efficiently than if heterozygous indv exhibit dominant phenotype and shield the recessive allele

Question 15

What is secondary contact? What are the possible outcomes of it?

Answer 15

When extrinsic barrier disappears and populations allowed to mate. speciation now depends on intrinsic
barriers.
b. Outcome 1: hybrids equally/more fit than parental - species will merge.
c. Outcome 2: hybrids less fit in parental ranges but equally/more fit in hybrid zone, then stable hybrid zone
will form.
d. Outcome 3: Hybrid less fit everywhere relative to parental, natural selection will reinforce reproductive
isolating mechanisms and speciation occurs

Question 16

Outcome when hybrids equally/more fit than parenta

Answer 16

species will merge.

Question 17

Outcome when hybrids less fit in parental ranges but equally/more fit in hybrid zone

Answer 17

stable hybrid zone

will form.

Question 18

Outcome when Hybrid less fit everywhere relative to parental

Answer 18

natural selection will reinforce reproductive

isolating mechanisms and speciation occurs

Question 19

What is reinforcement and what does it accomplish?

Answer 19

When hybrid offspring are unfit and natural selection reinforces reproductive isolation mechanisms,
changing postzygotic isolation to prezygotic isolation

Question 20

Glaucophytes

Answer 20

Unicellular aquatic 
photosynthetic organisms, 
some with 
flagella; Chloroplast derived from 
primary endosymbiosis and 
retains peptidoglycan (from 
cyanobacterial cell wall) 
between inner and outer 
membrane

Question 21

Red algae

Answer 21

Reddish accessory 
photosynthetic pigment 
masks green chloroplasts 
in low light; marine, 
multicellular, often 
attach by holdfast; Secrete calcium 
carbonate, enhance 
formation of coral reefs

Question 22

“green algae”

Answer 22

Unicellular, colonial, 
multicellular
• Two kinds of 
chlorophyll, store 
photosynthetic 
products as starch; Among green plants, 
“green algae” are 
basal to land plants

Question 23

liverworts

Answer 23

Simplest land plants, 
small leaf-like sheets 
of tissue as the visible 
organism, attach by 
hair-like rhizoids;Terrestrial but very 
moist circumstances

Question 24

mosses

Answer 24

Larger, more 
complex than 
liverworts—stomata, 
dead cell tubes for 
transport;Moist terrestrial 
habitats, form lush 
mats; Decaying layers in 
water form peat 
bogs

Question 25

microphyll

Answer 25

small leaf with single unbranched vein; originally formed from little outgrowths of sporangia, spore making structures

Question 26

megaphyll

Answer 26

big leaf with multiple branching veins; leads to evolution of true leafy structures

Question 27

ferns

Answer 27

Megaphylls with 
stomata, xylem, and 
phloem—terrestrial but 
moist quiet habitats 
(lack strong support) 
• Spores airborne, 
gametes by water

Question 28

synapomorphy of green plants

Answer 28

chlorophyll b; starch storage

Question 29

green plants

Answer 29

green algae + land plants

Question 30

synapomorphies of vascular plants

Answer 30

have systems to transport food and water throughout plant; microphyll and megaphylls; stomata

Question 31

plant tree

Answer 31

Plantae
Glaucophytes
(un-named taxon) 
Red algae 
Green Plants 
“Green algae” 
Land plants 
“Basal land plants” 
Vascular plants
Ferns 
Seed plants

Question 32

green plant with protected embryo but no seeds

Answer 32

liverworts, mosses, ferns

Question 33

Population genetics

Answer 33

evolutionary processes within populations over small time scales

Question 34

evolution

Answer 34

any genetic change in a population over time

Question 35

genetic change may occur through

Answer 35

mutation, migration, genetic drift, natural selection

Question 36

population

Answer 36

group of interbreeding individuals

Question 37

mutation

Answer 37

any heritable changes to DNA

Question 38

Evolution requires

Answer 38

genetic variation in the population

Question 39

polymorphisms

Answer 39

mutations that are segregating in a population; give evolutionary advantage, an evolutionary disadvantage, or have no effect at all

Question 40

every human, every generation, there are _____ mutations

Answer 40

10

Question 41

in entire world

Answer 41

every nucleotide is mutated every gneeration

Question 42

evolution

Answer 42

any change in allele frequency in a population over time

Question 43

gene

Answer 43

a genetic locus coding for a functional RNA transcript; almost always codes for protein

Question 44

locus

Answer 44

any defined segment of DNA; may not code for proteins

Question 45

polymorphic

Answer 45

locus is polymorphic if it has 2 or more alleles

Question 46

phenotype can be determined by

Answer 46

genotype or environmental conditions; combination of both

Question 47

Gene pool

Answer 47

all the gene copies present in a population (2 per diploid individual, therefore 2N total for a population size N)

Question 48

allele frequency

Answer 48

number of one allele (2 x AA + Aa) /total number of alleles (2 x (AA + Aa + aa)

Question 49

How does drift affect smaller populations

Answer 49

o Higher probability of large frequency jumps in any given generation
o Shorter expected time to fixation or loss