Fig. 10-1a, p.152

Fig. 10-1b, p.152

ATP ATP

p.153

Fig. 10-2, p.154

a Garden pea flower, cut in half. Sperm form in pollen grains, which originate in male floral parts (stamens). Eggs develop, fertilization takes place, and seeds mature in female floral parts (carpels).

b Pollen from a plant that breeds true for purple flowers is brushed onto a floral bud of a plant that breeds true for white flowers. The white flower had its stamens snipped off. This is one way to assure cross-fertilization of plants.

c Later, seeds develop inside pods of the cross-fertilized plant. An embryo within each seed develops into a mature pea plant.

d Each new plant’s flower color is indirect but observable evidence that hereditary material has been transmitted from the parent plants.

Fig. 10-3, p.154

carpel stamen

b A gene locus (plural, loci), the location for a specific gene on a chromosome. Alleles are at corresponding loci on a pair of homologous chromosomes

d Three pairs of genes (at three loci on this pair of homologous chromosomes); same thing as three pairs of alleles.

Fig. 10-4, p.155

a A pair of homologous chromosomes,both unduplicated. In most species, oneis inherited from a female parent and itspartner from a male parent.

c A pair of alleles may be identicalor not. Alleles are represented in the text by letters such as D or d.

fertilization produces heterozygous offspring

meiosis II

meiosis I

(chromosomes duplicated

before meiosis)

Homozygous dominant parent

Homozygous recessive parent

(gametes) (gametes)

Fig. 10-5, p.156

Trait Studied

Dominant Form

Recessive Form

F2 Dominant-to-Recessive

Ratio

Seed shape

Seed color

Pod shape

Pod color

Flower color

Flower position

Stem length

2.98:1

3.01:1

2.95:1

2.82:1

3.15:1

3.14:1

2.84:1787 tall 277 dwarf

651 long stem 207 at tip

705 purple 224 white

152 yellow428 green

299 wrinkled882 inflated

6,022 yellow 2,001 green

5,474 round 1,850 wrinkled

Fig. 10-6, p.156

female gametes

mal

e g

amet

es

Fig. 10-7a, p.157

a From left to right, step-by-step construction of a Punnett square. Circlessignify gametes. A stands for a dominant allele and a for a recessive allele atthe same gene locus. Offspring genotypes are indicated inside the squares.

A

A A A A

AAAAA

Aa

AaAa

AaAaaa aa aa aa

a

a

a

a

a

a

a

a

Fig. 10-7b, p.157

A

AA

Aaa Aa

AaAa

A

a

aa

Aa Aa

AaAa

True-breeding homozygousrecessive parent plant

F1 offspring

b Cross between two plants that breed true for different forms of a trait.

True-breeding homozygousdominant parent plant

Fig. 10-7c, p.157

AAa

AAa

Aa

a

a

Aa

AA Aa

aaAa

F2 offspring

HeterozygousF1 offspring

HeterozygousF1 offspring

c Cross between heterozygous F1 offspring.

aa

AA

p.165

the expectedphenotypicratio of 3:1

(dominant)(dominant)(dominant)(recessive)

AA AAAaAaaa

aa

Aa

Aa

A

A

a

a

Fig. 10-9, p.159

parent homozygous recessivefor white flowers, short stemsGametes at fertilization

parent homozygous dominantfor purple flowers, tall stems

Meiosis, gamete formationin true-breeding parent

plants

Possible genotypes resulting from a cross between two F1 plants:meiosis,gameteformation

All F1 plants are AaBbheterozygotes with purpleflowers and tall stems.

meiosis,gameteformation

Fig. 10-10, p.160

Phenotypes(Blood type):

Genotypes:

A AB B O

or

ABAO BO OO

BBAAor

Fig. 10-11, p.160

Cross two of theF1 plants, andthe F2 offspringwill show threephenotypes ina 1:2:1 ratio:

homozygousparent (RR)

homozygousparent (rr)

heterozygousF1 offspring (Rr)x

RR Rr Rr rr

Fig. 10-13, p.161

EB Eb eB eb

EB

Eb

eB

eb EeBbblack

EeBBblack

EEBbblack

EEBBblack

EEBbblack

EeBBblack

EeBbblack

Eebbchocolate

EeBbblack

EEbbchocolate

EeBbblack

Eebbchocolate

eeBByellow

eeBbyellow

eebbyellow

eeBbyellow

Fig. 10-16, p.163

p.164

Fig. 10-19a, p.164

Range of values for the trait

This red graph line of therange of variation for a traitin a population plots out asa bell-shaped curve. Suchcurves indicate continuousvariation in a population.

Nu

mb

er

of

ind

ivid

ual

sw

ith

a m

eas

ura

ble

val

ue

fo

r th

e t

rait

Fig. 10-19c, p.164

Fig. 10-20a-b, p.166