Lecture 4 - Reproductive Biology

Question 1

vegetative (clonal) propagation increases a weed’s ________ ability and ________

Answer 1

colonizing, persistance

Question 2

what are the benefits of selfing and outcrossing

Answer 2

selfing - guarantees some mating success even if only one plants exists
outcrossing - avoids inbreeding depression and creates new genotypes

Question 3

t/f: most clonally propagated species can only produce seeds asexually

Answer 3

f, they can typically also reproduce sexually

Question 4

asexual reproduction

Answer 4

creation of new individuals without involving genetic recombination

Question 5

what environments favour asexual reproduction

Answer 5

harsh environments and lack of mates

Question 6

2 types of asexual reproduction

Answer 6

vegetative reproduction
agamospermy (apomixis)

Question 7

vegetative reproduction

Answer 7

clonal growth (generally accompanied by seed production)

Question 8

agamospermy (apomixis)

Answer 8

creation of a seed without fertilization

Question 9

ramet

Answer 9

each independent offspring from vegetative reproduction (genetically identical, but physiologically independent)

Question 10

genet

Answer 10

entire genetic individual

Question 11

rhizomes

Answer 11

underground horizontal stem

Question 12

stolons

Answer 12

above-ground horizontal branch

Question 13

tubers

Answer 13

underground storage organ lasting 1 yr

Question 14

shoot bases

Answer 14

bulbs, corms

Question 15

root suckers

Answer 15

new shoots arise from buds on creeping roots or taproots

Question 16

vegetative reproduction advantages

Answer 16

-allows existence at limits of range where pollination/seed production iffy
-assures reproduction will low mortality
-rapid development with shortened time to flowering

Question 17

vegetative reproduction disadvantages

Answer 17

-restricted to short-distance dispersal
-limits genetic re-combi natation

Question 18

2 types of vegetative spread

Answer 18

expanding front/phalanx strategy
guerilla strategy

Question 19

expanding front/phalanx strategy (vegetative spread)

Answer 19

weeds advance as moving front as densely aggregated ramets (dispersal distance relatively short)

Question 20

guerilla strategy (vegetative spread)

Answer 20

forms loosely aggregated ramets that spread along main axis separated by distance
can invade new areas but never dominate

Question 21

phalanx strategy _______ invasion

Answer 21

resists

Question 22

guerilla strategy ________ invasion

Answer 22

does not resist

Question 23

phalanx strategy spreads _________

Answer 23

very slowly

Question 24

Guerilla strategy spreads _______

Answer 24

rapidly

Question 25

which weeds families most commonly reproduce through apomixis

Answer 25

Composite (sunflower/daisy/aster) rose, and grass families

Question 26

sexual reproduction

Answer 26

pollination required to fertilize egg and produce seed (cross or self-pollination)

Question 27

autogamy

Answer 27

fusion of nuclei derived from the same zygote but from different meiosis (all forms of self-fertilization) (sexual)

Question 28

allogamy

Answer 28

cross fertilization; out-crossing (sexual)

Question 29

how does the mating system of a weed influence its population structure

Answer 29

highly selfed - differences among populations results in identifiable biotypic variation among pop highly out-crossed - populations characterized by a high degree of variability

Question 30

t/f: outcrossing facilitates rapid spread of new traits

Answer 30

t

Question 31

sexual reproduction advantages

Answer 31

-produces genetically variable individuals -produces more fit genotypes avoid accumulation of deleterious alleles -allows kids to leave home

Question 32

sexual reproduction disadvantages

Answer 32

-sex costs resources -sex breaks up happy homes (well established genotypes or populations)

Question 33

________ is another form of gene flow

Answer 33

seed movement

Question 34

________ constitutes a major form of gene flow

Answer 34

pollen movement

Question 35

wild mustard is a _______ flower

Answer 35

perfect

Question 36

monoecious

Answer 36

separate male and female flowers on the same plant

Question 37

which common broadleaf weeds have highly selfing mating systems

Answer 37

wild buckwheat cleavers hemp nettle purslane common groundsel canada fleabane

Question 38

which common broadleaf weeds have highly outcrossing mating systems

Answer 38

perennial sow thistle common toadflax purple loosestrife russian thistle

Question 39

which common broadleaf weeds have both selfing and out-crossing mating systems

Answer 39

night-flowering catchfly leafy spurge lambs quarters stinkweed

Question 40

highly self pollinated grasses

Answer 40

green foxtail, downy brome

Question 41

obligate outcrosser in grasses

Answer 41

annual ryegrass