Plants

Question 1

What are the characteristics of the Kingdom Plantae?

Answer 1

These are multicellular eukaryotes, photosynthetic autotrophs (chloroplasts with chlorophyll a and b). Land plants evolved from aquatic green algae of the phylum Charophyta. The plant life cycle is called the Alternation of Generations.

Question 2

Describe the Alternation of Generations.

Answer 2

Part of life cycle as a haploid adult - as a gametophyte (n). Gametophytes make gametes. The other part of life cycle as diploid adult - as a sporophyte (2n). Sporophytes make spores. Proportion of the life cycle occupied by gametophyte and sporophyte varies among plants.

Question 3

Sporophytes (2n) produce _____ (n) by _____.

Answer 3

Sporophytes (2n) produce spores (n) by meiosis.

Question 4

Spores (n) develop into _____ by _____.

Answer 4

Spores (n) develop into gametophytes by mitosis. This occurs if spores find themselves in favorable conditions for growth.

Question 5

Gametophytes (n) produce _____ (n) by _____.

Answer 5

Gametophytes (n) produce gametes (n) by mitosis.

Question 6

Gametes (n) fuse to from _____ (_____).

Answer 6

Gametes (n) fuse to from zygotes (2n).

Question 7

Zygotes (2n) develop into _____ (2n) by _____.

Answer 7

Zygotes (2n) develop into sporophytes (2n) by mitosis.

Question 8

What evidence is there for evolution from green algae?

Answer 8

1. The chloroplasts found in Charophyta and in land plants are homologous (similar).
2. Both Charophyta and land plants have cell walls made of cellulose.
3. Both store food as starch.
4. Both have similar sperm structure.
5. There are similarities in mitosis and cytokinesis.

Question 9

What general difference is there between plants and green algae?

Answer 9

Plants have more complexity and cell specialization than green algae.

Question 10

List the four possible adaptations that land plants would have and that green algae wouldn’t.

Answer 10

1. Roots or root-like structures.
2. Conducting vessels (vascular tissue).
3. Reproductive adaptations.
4. Dehydration prevention.

Question 11

What is the benefit of roots or root-like structures in land plants?

Answer 11

Roots or root-like structures anchor the plant on land and absorb water and nutrient from the soil.

Question 12

What is the benefit of conducting vessels (vascular tissue) in land plants?

Answer 12

These are a network of tubes that allow for the transport of water and minerals from the roots to throughout the plant (xylem) or for the transport of photosynthetic products throughout the plant (phloem).

Question 13

What is the benefit of reproductive adaptations in land plants?

Answer 13

Pollen (containing sperm) can be dispersed by wind or by animals and does not require water to swim to the ovule (which contains the female gamete). Seeds are protected from UV radiation and can be dispersed by animals and wind and contains its own food source. The existence of 2 multicellular forms: haploid gametophyte and diploid sporophyte, which has an extra copy of DNA which increases genetic variation and better adaption of the environment.

Question 14

How have land plants evolved to prevent dehydration?

Answer 14

Leaves have waxy cuticles, a waxy substance that prevents gases and water from leaving the leaf (prevents drying out). And so land plants have also developed stomata (pores in their leaves) for gas exchange and water evaporation.

Question 15

Describe a stoma (many stomata).

Answer 15

Stomata are pores in the leaves and stems of land plants. These are used to control gas exchange (CO2 in and O2 out) as the waxy cuticle prevents these gasses from leaving or entering the leaf cells easily. Water also evaporates through these pores.

Question 16

What are the four land plant phyla (pertaining to this course) and what type of plants do they encompass?

Answer 16

1. Bryophyta (mosses, liverworts and hornworts).
2. Pterophyta (ferns).
3. Gymnosperms / Coniferophyta (conifers, evergreens).
4. Angiosperms / Anthophyta (flowering plants).

Question 17

Describe the bryophytes.

Answer 17

Mosses, liverworts and hornworts are all seedless, nonvascular (water moves over the surface and nutrients move in by diffusion). For this reason, they grow low to the ground. The gametophyte generation is dominant - sporophytes are smaller and dependent on the gametophyte. These require water for fertilization because the sperm must swim to the egg. They contain primitive roots called rhizoids, which anchor the plant to land.

Question 18

Explain how the bryophyte is different than the basic alternation of generations life cycle.

Answer 18

The spore, produced by the sporophyte, is the dispersal phase. Female gametophytes produce the eggs and the sperm swims to then fertilizes the egg to become a zygote that will develop into a diploid sporophyte (which grows out of a female gametophyte). This is why the sporophyte is dependent on the gametophyte.

Question 19

Which of the 4 land plant groups are also vascular plants?

Answer 19

Pterophytes, gymnosperms / Coniferophyta & angiosperms / Anthophyta.

Question 20

What are the two types of vascular tissue?

Answer 20

Xylem and phloem. Plants containing vascular tissue have true roots. These roots can bring nutrients throughout the plant, unlike rhizoids which only keep the plant in place.

Question 21

Describe xylem.

Answer 21

Xylem conducts water and minerals from the root to the rest of the plant. It is composed of dead, tube-shaped cells which form a microscopic water-pipe system. The xylem is supported by lignin, which is embedded in the cell wall (within the cellulose).

Question 22

Describe phloem.

Answer 22

This vascular tissue conducts food (organic compounds; products of photosynthesis) made in the leaves throughout the plant. It is composed of living cells arranged into tubules.

Question 23

Describe the pterophytes.

Answer 23

Pterophytes, such as ferns, are seedless but vascular. Sporophyte is the dominant life stage. Gametophytes are however independent, small and grow on or below the surface. Though the presence of a vascular system means that water in not required for nutrients, water is needed for fertilization because the sperm must swim to the egg.

Question 24

Describe the pterophyte life cycle.

Answer 24

Spores, produced by sporophyte, is the dispersal phase. The gametophyte produces both eggs and flagellated sperm (in different parts of the gametophyte). The sporophyte develops from a zygote.

Question 25

How do sperm from a gametophyte pterophyte reach the eggs on another part of the gametophyte?

Answer 25

Pterophytes require water for fertilization. When it rains, the sperm can swim down to the eggs of the gametophyte.

Question 26

Which of the 4 land plant phyla are also seed plants?

Answer 26

Gymnosperms / Coniferophytes & angiosperms / anthophytes.

Question 27

What is a seed?

Answer 27

A seed is a sporophyte embryo, surrounded by a food supply and a protective coat. An embryo is formed when the female gamete (within the ovule) is fertilized by the male gamete (sperm). The resulting diploid zygote will grow into the embryo which will eventually develop into the new sporophyte.

Question 28

Describe gymnosperms / coniferophytes.

Answer 28

These have seeds and are vascular. Sporophyte is the dominant life stage (tree). Gametophytes are reduced (microscopic) and are no longer independent from sporophytes. Male gametophyte in pollen grain (carried by animals or blown by wind). Female gametophyte found in the ovule. Their seed is naked (not surrounded by fruit tissue) and is found on the cone in gymnosperms. Seeds are dispersed by wind or animals.

Question 29

Which plant group includes some of the largest, tallest and oldest plants on the planet?

Answer 29

Phylum Coniferophyta (gymnosperms).

Question 30

What are the two different types of cones that gymnosperms produce?

Answer 30

Coniferophytes produce small pollen cones (male) which produces pollen grain which contains the male gametophyte (contains sperm). They also produce the ovulate cone (female), which contains the female gametophyte, which consists of multicellular nutritive tissue and the female gamete (egg cell). The ovule develops into the seed after feralization and these seeds are dispersed by the win after scales of the ovulate cone separate (open).

Question 31

Describe the coniferophyte life cycle.

Answer 31

Pollen grains and seeds can be dispersed over large distances. Male gametophytes produce male gametes (in pollen grain). Females gametophytes produce females gametes (in ovule). Fertilization creates a diploid embryo that develops within a seed. Seed will germinate and grow into a diploid sporophyte.

Question 32

Describe angiosperms / Anthophyta.

Answer 32

These are the youngest, most evolved land plants. They contain flowers, seeds, fruits and vascular tissues. Sporophyte is the dominant life stage; gametophytes are reduced and are no longer independent.

Question 33

Describe the flower of an angiosperm.

Answer 33

The flower is the reproductive structure of the plant (male and female organs). Its colour and scent attracts pollinators (such as bees) which carry pollen from one flower to another (same species).

Question 34

Describe the seed of an angiosperm.

Answer 34

These are held in
a protective, enclosed chamber at the base of the flower called the ovary (non-naked, meaning they have fruit and vascular tissue around them). The ovary matures into fruit.

Question 35

Describe the fruits of an anthophyte.

Answer 35

Fruits aid with seed dispersal. They can be propeller shaped and carried by the wind, they can be burrs that cling to animal fur and can be eaten by animals and passed through the digestive tract.

Question 36

What is the stamen?

Answer 36

The stamen is the male reproductive structure of the flower, which produces pollen.

Question 37

What is the carpel? What else is it called?

Answer 37

The carpel is the female reproductive structure of the flower. It contains ovules and is also called the pistil.

Question 38

Fruits develop from the ovary _____.

Answer 38

The ovary itself will transform into the rest of the fruit.

Question 39

Describe the angiosperm life cycle.

Answer 39

Pollen grains and seeds can be dispersed over large distances. Male gametophytes produce male gametes (in pollen grain) and female gametophytes produce female gametes (in ovule). Fertilization creates a diploid embryo that develops within a seed (seed is surrounded by fruit tissue). Seed will germinate and grow into a diploid sporophyte.

Question 40

What are the defining characteristics of a fruit?

Answer 40

A fruit is a seed-bearing structure that develops from the ovary of a flowering. Seedy outgrowths such as apples, squash and tomatoes are all fruits.

Question 41

What are vegetables?

Answer 41

A vegetable is another plant part, such as roots, leaves and stems. Roots such as beets, potatoes and turnips, leaves such as spinach, kale and lettuce and stems such as celery and broccoli are all vegetables.

Question 42

All four land-plant phyla have _____ _____ and _____.

Answer 42

All four land-plant phyla have waxy cuticles and stomata.

Question 43

Only _____ and _____ require H2O for fertilization.

Answer 43

Only Bryophyta and Pterophyta require H2O for fertilization.

Question 44

Only Bryophyta doesn’t have _____ in their cell walls.

Answer 44

Only Bryophyta doesn’t have lignin in their cell walls. Xylem is supported by lignin embedded in the cell wall.

Question 45

Gametophyte is the dominant life stage of what plant group?

Answer 45

Bryophyta.

Question 46

Which land-plant group does not have true roots?

Answer 46

Bryophyta.

Question 47

Which two land-plant groups have seeds and pollen?

Answer 47

Coniferophyta and Anthophyta.

Question 48

Which land-plant group has fruits and flowers?

Answer 48

Anthophyta.