Download Angiosperms

PLANT DIVERSITY II: QUESTION ANSWERS
1. Contrast how sperm reaches eggs in seedless plants vs in seed plants.
In seedless plants (moss, fern) the sperms swims through a thin film of
water on the plant to reach the egg in the arachegonium.
2. What features not present in seedless plants, have contributed to the great
success of seed plants on land? (list, describe, state evolutionary advantage)
1. Reduced gametophyte – the gametophyte generation is very small. The
advantage is that is protected from drying out and receives is nutrients
from the sporophyte, increasing its chances of surviving.
2. Heterospory – seed plants produce two types of spores. This allowed for
spores to develop different traits to carry out their jobs better (eggs
larger, stay within the sporangium). It also allows for increased variation
in offspring.
3. Ovules – the megasporangium, megaspore, and protective covering. These
for the seed, which , because of the protective covering and food source,
can go dormant and can disperse over longer distances.
4. Pollen and the production of sperm. The pollen grain contains the sperm.
The wall of the pollen includes sporopollenin, and protects the pollen
grain. Pollen can be dispersed by the wind, allowing for sexual
reproduction over longer distances.
5. Seeds are structures made up of an embryo sporophyte, a food source,
and a protective covering. They allow the embryo to survive harsh
weather conditions like cold or winter or lack of water in a dry season.
They are specialized for dispersal by wind, water, animals, ensuring the
propagation of the species.
3. Distinguish between homosporous and heterosporous.
Homosporous plants produce only one type of spore.
Heterosporous plants produce two types of spores, sperm and eggs.
4. Explain how the life cycle of a pine reflects the five adaptations found in all
seed plants.
The pine life cycle illustrates heterospory, as ovulate cones produce
megaspores and pollen cones produce microspores.
The reduced gametophytes are evident in the form of the microscopic pollen
grains that develop from microspores and the microscopic megaspore that
develops from the the megaspore.
The egg develops within the ovule, and a pollen tube allows the sperm to
reach the egg.
The seed contains a food source and a protective seed coat.
5. Why is a gymnosperm seed said to be “naked” and how does it compare to a
seed produced by an angiosperm? The gymnosperm seed is naked because it
does not develop within an ovary as the angiosperm seed does.
6. List adaptations seeds have to aid dispersal.
Wings and fluffy fiber structures that allow seeds to be dispersed by wind.
Seeds within edible fruit that are able to withstand the low pH of a
digestive tract as they pass through an animal.
Barbs and hooks that snag a seed into the fur of an animal.
Ability to float, allowing dispersal by water (coconut)
7. List the characteristics of an angiosperm.
Flowers, Fruit, double fertilization, vascular tissue, seeds, true roots, true
leaves
8. Draw and label the three parts to a seed.
9. What is the result of double fertilization?
One sperm fertilized the egg to produce the 2N zygote (which forms the
embryo). The other sperm joins with the 2 nuclei in the large central cell of
the female gametophyte, forming a 3N (called triploid) endoperm. The
endosperm is a source of nutrients for the embryo when it germinates.
10. Explain how plant diversity can be considered a non-renewable resource.
Species of plants have evolved over hundreds of thousands or millions of
years. If a plant becomes extinct, we, as humans, cannot replace it. It and
its potential as a source of medicine or other useful biochemical substance is
lost.
11. Contrast a gymnosperm (pine) life cycle with an angiosperm life cycle.
Both gymnosperms and angiosperms have dominant sporophyte generations.
Both produce two types of gametes from gametangia (archegonia and
antheridia). They differ in that the eggs and sperm are produced in two
differed cones in a gymnosperm. Eggs and sperm are produced in flowers in
angiosperms, that may produce both types of gametes, or just one,
depending on the species of plant. Generally gymnosperms take 3 years to
complete the gamete to mature seed stage. Angiosperms usually complete
the process within a few months.
12. List and describe 7 differences between monocots and eudicots.
Monocots
Eudicots
1 cotlyledon
2 cotyledons
Vascular tissue in scattered
Vascular tissue forms a ring
Pattern
Fibrous roots
Tap root
Pollen with 1 pore
Pollen with 3 pores
Leaves have parallel veins
Leaf veins from a network pattern
Flower parts in sets of 3
Flower parts in sets of 4 or 5
No petiole, forms sheath
Petiole
Generally only has primary growth
Some species have secondary growth
13. What six crops provide most of the food calories consumed by humans?
Wheat, rice, corn, cassava, sweetpotato, potato
14. Compare the timeframe to produce seeds in gymnosperms and seeds in
angiosperms. Gymnosperm process takes about 3 years, angiosperms
generally several months.
15. List several adaptations of gymnosperms.
Dominant sporophyte generation, vascular tissue, seeds develop from
fertilized ovules, transfer of sperm to ovule via pollen grain, heterosporous.
Form (naked ) seeds.
16. List several uses of gymnosperms by man.
Lumber, medicines (Sudafed, taxol), turpentine, food (pine nuts)
17. Label the structures and stages of the life cycle of the pine:
18. How does the angiosperm life cycle differ from a general alternation of
generations? The gametophytes are small, short lived.
19. Label the life cycle of the angiosperm.
20. Describe and give an example of co-evolution.
Some species interact so intimately that they can cause evolutionary changes in each other over
time. This is called coevolution. In coevolution, when one species develops an evolutionary
advantage, it triggers a change in a closely associated species. This change may then cause
another evolutionary change in the first species. A species of moth called the Morgan's sphinx
moth has a proboscis, or tongue, that is almost 12 inches long. This is more than three times its
entire body length. Why would a moth need such a long tongue? Because of the flower it feeds
on.
21.
The following is a phylogenic tree of all plants:
Charophytes
Green algae,
Ancestor of plants
Bryophytes
(mosses)
Pterophytes
(Ferns)
Gymnoperms
Angiosperms
22. Where in an angiosperm would you find the megasporangium?
a. In the style of the flower.
b. Inside the tip of of a pollen tube
c. Enclosed in the stigma of a flower
d. Within an ovule contained within an ovary of a flower
e. Packed into pollen sacs within the anthers found on a stamen
23. A fruit is most commonly
a. A mature ovary
b. A thickened style
c. An enlarged ovule
d. a modified root
e. a mature female gametophyte
24. With respect to angiosperms, which of the following is incorrectly paired
with its chromosome count?
a. Egg – 1N
d. zygote – 2N
b. Megaspore – 2N
e. sperm – 1N
c. Microspore – 1N
25. Which of the following is not a characteristic that distinguishes
gymnosperms and angiosperms from other plants?
a. Alternation of generations
d. pollen
b. Ovules
e. dependent gametophyte
c. Integuments
26. Gymnosperms and angiosperms have the following in common except
a. Seeds
b. pollenc. vascular tissue
d. ovaries e. ovules
27. Label on the following phylogenic tree , where each of the following derived
characteristics appear:
a. Flowers
b. Embryos
c. Seeds
d. Vascular tissue
Charopyte green algae
Mosses
B
Ferns
D
Gymnosperms
C
A
Angiosperm