Chapter 30: Plant Diversity II

Question 1

Advantages of reduced gametophytes?

Answer 1

• Protects gametophytes from environmental stresses; enables developing gametophytes to obtain nutrients from parental sporophyte

Question 2

Ovules + Protection of Eggs

Answer 2

• Integument envelops and protects the megasporangium

- Whole structure is an ovule, inside female gametophyte develops from megaspore

Question 3

Pollen grain

Answer 3

• Microspore develops into these; consist of male gametophyte enclosed within pollen wall
• Transfer of pollen to part of seed plant that contains the ovules is pollination

Question 4

Advantages of seeds

Answer 4

• Single-celled
• Remain dormant for months or years
• Supply of stored food

Question 5

Gymnosperms

Answer 5

• Bear naked seeds typically on cones

Question 6

Conifers

Answer 6

• Cone-bearing plants (gymnosperms)

- Pines, firs, redwoods

Question 7

Life Cycle of a Pine

Answer 7

• (2n) Each tree has both ovulate and pollen cones
• Microsporocytes divide by meiosis; produce haploid microspores–>pollen grains
• Ovulate cone scale has two ovules (each contain megasporangium)
• Pollination occurs when pollen gain reaches the ovule; pollen grain germinates to form pollen tube
• Pollen tube develops and megasporocyte undergoes meiosis to produce four haploid cells (one survives as megaspore)
• Megaspore develops into female gametophyte that contains 2-3 archegonia; each of which will form an egg
• By the time eggs are mature, sperm cells have developed in pollen tube (extends into female gametophyte)
• Fertilization occurs when sperm + egg nuclei unite

Question 8

First seed plants

Answer 8

• 360 million years ago

Question 9

Dominant life stage for mosses/nonvascular

Answer 9

Gametophyte

Question 10

Dominant life stage for ferns/seedless vascular

Answer 10

Sporophyte

Question 11

Dominant life cycle for seed plants

Answer 11

Sporophyte

Question 12

Gymnosperms in Plant Phyla

Answer 12

• Cycadophyta
• Gingkgophyta
• Gnetophyta
• Coniferophyta

Question 13

Characteristics of Angiosperms

Answer 13

• Flower
• Petals
• Stamens: produce microspores that develop into pollen
• Filament: Stalk that comprises stamen
• Anther: Terminal sac where pollen is produced
• Carpels: make megaspores; female gametophytes
• Stigma: Tip of carpal that receives pollen

Question 14

Complete flowers

Answer 14

Have all four organs

Question 15

Fruits

Answer 15

Seed develops from ovules after fertilization, ovary wall thickens and matures into fruit

Question 16

Angiosperm Life Cycle

Answer 16

• Megasporangium of each ovule: Megasporocyte divides by meiosis to produce four megaspores; one survives
• On anther, microsporangium contain microsporocytes that divide by meiosis
• Microspore develops into pollen grain; generative wall will divide
• Pollination: Two sperm cells are discharged in each ovule
• Double fertilization occurs; on forms zygote and other forms endosperm
• Zygote develops into an embryo that is packaged along with food into a seed
• Seed germinates and embryo develops into mature sporophyte

Question 17

Micropyle

Answer 17

Pore in integuments of ovule

Question 18

Cotyledons

Answer 18

Rudimentary root, and on or two seed leaves

Question 19

Endosperm

Answer 19

Tissue rich in starch and other food reserves that nourish the developing embryo

Question 20

Monocot

Answer 20

• One cotyledon
• Embryos
• Leaf venation
• Root system usually fibrous
• Pollen grain with one opening

Question 21

Dicot

Answer 21

Two cotyledons

Question 22

Eudicots

Answer 22

• Two cotyledons
• Netlik veins
• Vascular tissue in a ring
• Taproot
• Pollen grain with three opening
• Floral organs usually in multiple of four or five