Unit Two: A Comparison Of Plants And Animals

Question 1

What are the characteristics of plants?

Answer 1

• eukaryotic
• multicellular (unlike algae, some algae are multicellular but not all)
• photosynthetic autotrophs (get their carbon from CO2)
• store carbohydrates as starch
• life cycle alternates between multicellular n and 2n phases (alternation of multicellular generation - haploid and diploid)

Question 2

What did plants evolve from?

Answer 2

Filamentous green algae

Oldest mega fossils dates back about 425mya

Plants probably evolved about 470mya (fossils of spores)

Question 3

What is the taxonomy chain?

Answer 3

Domain - kingdom - phylum - class - order - family - genus - species

Question 4

What are bryophytes?

Answer 4

They are haploid plants.

They have a diploid reproductive structure.

Question 5

What are examples of bryophytes?

Answer 5

Mosses, liverworts, hornworts

Question 6

Why can’t mosses grow tall?

Answer 6

Mosses can’t grow fall because they don’t have roots; they can’t keep nutrients. They are thin, and therefore fragile.

Question 7

What are features of the bryophytes (which are present in all plants)?

Answer 7

1. A waxy cuticle
   Covers all above-ground surfaces
2. Stomata (holes/openings)
   Used for gas exchange. Plants can’t exchange through cells because of the waxy coat.
3. Guard cells (specialized cells that can open or close the stomata)

2 & 3 cover all above-ground surfaces, allow gas exchange, decrease water loss

4. Alternation of generation (the dominant plant is haploid)
   Produces gametes using mitosis
   Fusion of gametes - diploid organ - produces spores using meiosis

Question 8

What are seedless vascular plants?

Answer 8

Diploid plants - produces spores

Smaller haploid plants - produces gametes

Question 9

What do all plants have?

Answer 9

Stomata, guard cells, egg and sperm, waxy cuticle

Question 10

What are examples of seedless vascular plants?

Answer 10

equisetum

ferns

Question 11

What are the features of seedless vascular plants?

Answer 11

-all features of bryophytes
-vascular tissue
phloem – conducts products of photosynthesis
Xylem – conducts water and minerals
contains lignin – a material in cell walls; provides support/strengthens cells and plant
dead xylem = woody tissue

Question 12

What are gymnosperms?

Answer 12

Diploid plant - produces spores

Haploid reproductive structure - produces gametes

Question 13

What are examples of gymnosperms?

Answer 13

conifers
cycads
ginko
gnetophytes

Question 14

What are features of gymnosperms?

Answer 14

• all the features of bryophytes and seedless vascular plants
• pollen - multicellular, haploid, male reproductive organ; produces sperm
• seeds = embryo (“baby” plant) + endosperm (food reserves); protected by seed coat

Question 15

What are flowering plants?

Answer 15

angiosperms

Question 16

What are examples of angiosperms?

Answer 16

monocots - grasses

dicots - trees, and most other plants

Question 17

What are features of angiosperms?

Answer 17

• all of the features of bryophytes, seedless vascular plants and gymnosperms
• develop from flowers
• the ovary
• remains with seed to provide protection
• all fruits contain seeds

Question 18

Where is pollen produced and released?

Answer 18

In the anther

Question 19

What are the steps of double fertilization in angiosperms?

Answer 19

1. pollen (male organ) contacts stigma (female organ)
2. If pollen and stigma are compatible, the pollen tube grows towards the ovule
3. 2 haploid sperms are released (produced via mitosis of cell in pollen)
4. One sperm nucleus fuses with the egg (ovule) nucleus and forms the zygote/embryo (2n)
5. The 2nd sperm nucleus fuses with 2 nuclei of the central cell and forms 3n endosperm.

the ovule will become the fruit

Question 20

What are the steps of embryo development in angiosperms?

Answer 20

1. double fertilization

2. seed development