Chapter 30 - Plant Diversity II

Question 1

What are the advantages of producing a seed?

Answer 1

• seeds can move away from the mother plant; do not have to be attached
• seed plants are dominant producers on land
• 12000 years ago humans began cultivating plants

Question 2

Name five derived traits of seed plants.

Answer 2

1) Reduced Gametophytes
2) Heterospory
3) Ovules
4) Pollen
5) Seeds

Question 3

Reduced gametophyte

Answer 3

microscopic male and female gametophytes (n) are nourished and protected by the sporophyte (2n)

Question 4

Heterospory and what types?

Answer 4

Other or different spores

microspore (gives rise to a male gametophyte) megaspore (gives rise to a female gametophyte)

Question 5

Ovules

Answer 5

Inside each ovule, a female gametophyte develops from a megaspore and produces one or more eggs

Question 6

Pollen

Answer 6

pollen grains make water unnecessary for fertilization; pollination occurs when pollen is transferred to the part of the seed plant that contains the ovules

Question 7

Seeds

Answer 7

survive better than unprotected spores; can be transported long distances (by wind or animals)

Question 8

Pollination Tip

Answer 8

• ovules not completely enclosed in sporophyte tissue at pollination

Question 9

Where is the female and male gametophyte located in a seed plant?

Answer 9

-

Question 10

What are the four groups of gymnosperms?

Answer 10

• Coniferophytes
• Cycadophytes
• Gnetophytes
• Ginkgophytes
• all lack flowers and true fruits

Question 11

Conifers

Answer 11

• largest gymnosperm phylum
• tallest and oldest vascular plants
  EX. pines, spruces, firs, cedars

Question 12

Pine (conifer)

Answer 12

• cluster of two to five tough, needle like leaves
• Produces male and female cones
• microsporangia develop into four-celled pollen grains
• megasporangium produces megaspores one of which becomes female gametophyte

Question 13

Cycadophytes

Answer 13

• resemble palms, but are not flowering plants
• heights of 15 meters or more
• produces cones
• some female cones can be huge
• sperm have flagella
• life cycle like that of conifers

Question 14

Gnetophytes

Answer 14

• only gymnosperms to have vessels in their xylem; vessels are a particularly efficient conducting cell type that is a common feature of angiosperms
  EX. Welwitschia from southwestern Africa
  EX. Ephedra found worldwide; source of ephedrine - taken off market in 2004 because linked to strokes and heart attacks

Question 15

Ginkgophytes

Answer 15

• only one species remains extant
• Ginkgo biloba has broad leaves that shed in fall
• sperm have flagella
• dioecious - separate male and female trees
• Fleshy covering of female seeds is very stinky like rancid butter

Question 16

Angiosperms

Answer 16

• more than 250000 known species
• enclosed ovules within diploid tissue at time of pollination
• produce fruit (from carpel)
• origins are a mystery

Question 17

Examples of Angiosperms

Answer 17

• Archaefructaceae (extinct family) may be sister clade, but debate continues
• Amborella trichopoda thought to be the closest living relative to the first angiosperm

Question 18

Flowers

Answer 18

• house the gametophyte generation of angiosperms

- are modified stems that bear modified leaves

Question 19

Flowers have four whorls

Answer 19

1) sepals - 3 to 5 and green, leaflike
2) petals - 3 to 5 and often colored
3) androecium = stamens
4) gynoecium = one or more carpels

Question 20

Stamens produce

Answer 20

produce haploid pollen (the male gametophyte)

Question 21

Carpel: 3 Major regions

Answer 21

• ovary, stigma, and style
• the carpel contains the female gametophyte
• the ovary becomes the fruit

Question 22

Fruits are adapted for

Answer 22

dispersal

Question 23

3 layers of ovary wall are:

Answer 23

• exocarp (outside)
• mesocarp (middle)
• endocarp (inside)

Question 24

All 3 layers of ovary wall are called:

Answer 24

pericarp

* fates of these layers determines whether the fruit is fleshy or dry and hard

Question 25

Fruits allow what to colonize large areas?

Answer 25

angiosperms

Question 26

Fruits with fleshy coverings that are black, blue, or red are dispersed by what?

Answer 26

Birds and vertebrates

Question 27

Fruits dispersed by birds and vertebrates have what?

Answer 27

A hard seed coat that is resistant to stomach acid or digestive enzymes

Question 28

Fruits with hooked spines (burrs) are dispersed by what?

Answer 28

animal fur or human's clothing

Question 29

What buries acorns and nuts that could result in sprouting in the spring?

Answer 29

squirrels and other mammals

Question 30

Fruits of maple, ash, and elm trees have what that aid in wind dispersal?

Answer 30

"wings"

Question 31

Orchids have what that aids in wind dispersal?

Answer 31

dust like seeds

Question 32

Dandelions have what that float on wind currents?

Answer 32

seeds with "parachutes"

Question 33

What other plants have similar adaptions for wind dispersal like dandelions?

Answer 33

Milkweeds, cottonwood trees, willows, goat's beard, and others

Question 34

How do coconuts practice dispersal?

Answer 34

They can float in water to disperse to another island

Question 35

Most species use flowers to attract pollinators and reproduce?

Answer 35

- nectarines - scent * some can be pollinated by wind, usually grass, trees, some flowers

Question 36

The angiosperm life cycle includes:

Answer 36

double fertilization

Question 37

Angiosperm Life Cycle

Answer 37

- Megaspore produces 8 haploid nuclei - Female gametophyte consists of embryo sac and the 8 nuclei in only 7 cells - Most important are the egg and the two polar nuclei in the single cell - Pollen grain (after landing on receptive stigma) forms pollen tube toward embryo sac - Two sperm pass through the tube - One fuses with egg to form zygote - Other sperm fuses with polar bodies to form triploid endosperm nucleus - Endosperm will nourish the embryo

Question 38

Monocots

Answer 38

- one cotyledon - parallel veins - scattered vascular tissue - fibrous root system - pollen grain with one opening - floral organs in multiples of three

Question 39

Eudicots

Answer 39

- two cotyledons - net like veins - vascular tissue arranged in a ring - taproot usually present - pollen grains with three openings - floral organs usually in multiples of 4 or 5

Question 40

In what ways do humans depend on seed plants?

Answer 40

food, wood, and many medicines

Question 41

Why should we be concerned about the destruction of habitat across the world?

Answer 41

threatens the extinction of many plant species and the animal species they support