Lecture 2- Major Groups of Land Plants and their Reproduction

Question 1

How many divisions are there of land plants

Answer 1

10

Question 2

General life cycle of animal

Answer 2

gametes, fertilization/syngamy— zygote(2n)—- multicellular adult (2n)—- meiosis—- gametes

Question 3

General life cycle of plant

Answer 3

gametophyte makes gametes
two gametes unite to produce zygote
zygote undergoes mitosis to become sporophyte
sporophyte undergoes meiosis to produce spores
spores develop into gametophyte via mitosis

Question 4

Meiosis in land plants

Answer 4

produces spores

Question 5

mitosis in land plants

Answer 5

produces gametes

Question 6

Four major groups of land plants

Answer 6

Mosses, ferns, conifers, angiosperms

Question 7

Mosses

Answer 7

• Division byophyta
• 15,000 species
• damp areas, swimming sperm and no vascular tissue
• no true leaves
• gametophyte dominant
• homosporous

Question 8

Moss gametophytes

Answer 8

• make gametes
• haploid
• little projections
• make either egg or sperm, not both

Question 9

Moss sporophytes

Answer 9

• arise from the gametophyte

- short lifespan, disintegrate after they release spores

Question 10

Life cycle of a moss

Answer 10

1- Males: haploid spore develops into protonemata
protonemata develops into male gametophyte antheridia that makes sperm
Females: spore develops into female gametophyte, archegonia. Makes egg

2. Sperm gets in water. Sperm lands on female gametphye archegonium and swims down. Fertilizes the egg to produces diploid cell, zygote
3. Diploid cell undergoes mitosis to develop into a sporophyte. Sporophyte arises out of gametophyte
4. Sporophyte undergoes meiosis to produce spores. Releases spores and sporophyte disintegrates

Question 11

Spores

Answer 11

• haploid

- not a gamete because they don’t unite

Question 12

Non vascular plants

Answer 12

• limited
• not morphologically diverse
• bryophytes
• gametophyte dominant

Question 13

Vascular plants

Answer 13

• sporophyte dominant
• xylem and phloem
• tracheophytes
• cell walls with lignin, allows growth in tall

Question 14

vascular tissue

Answer 14

xylem and phloem

Question 15

xylem

Answer 15

• controls water and mineral flow
• to inside
• tracheids

Question 16

phloem

Answer 16

• transports sugars

- to outside

Question 17

Ferns

Answer 17

• division pterophyta
• 20,000 species
• appeared approx 400mya
• ptero: means wing or feathered
• vascular plants
• sporophyte dominant
• swimming sperm
• homosporous or heterosporous

Question 18

Life cycle of a fern

Answer 18

1- Sporangium release spores that develop into bisexual photosynthetic gametophyte
2- Each gametophyte has Antheridia makes sperm, archegonia makes egg
3- Water transmits sperm, fertilizes egg in archegonia to produce diploid zygote
4- Zygote develops into sporophyte, sporophyte takes over and gametophyte withers away
5- On sporophyte are sorus that contains clusters of sporangium. Sporangium undergoes meiosis to produce spores
6- Sporangium releases spores

Question 19

sorus

Answer 19

cluster of sporangium

Question 20

sporangium

Answer 20

• where spores produced
• diploid structure that makes haploid sperms
• produces 64
• releases spores

Question 21

Homospory

Answer 21

-makes one size spore
-all mosses, most ferns
Sporangium produces single size spore, spore develops into typically bisexual gametophyte, gametophyte produces egg and sperm

Question 22

Heterospory

Answer 22

Megasporangium produces 4 spores, surviving one is megaspore, megaspore turns into female gametophyte (archegonium), produces egg

Microsporangium produces microspores, microspore turns into male gametophyte antheridia, makes sperm

Question 23

Difference between male and female in all life

Answer 23

• size of gametes
• female has bigger gametes
• male has smaller gametes

Question 24

difference between mosses and everything else

Answer 24

-vascular tissue

Question 25

5 divisions of seed plants

Answer 25

``` 1- Cyanophyta 2-Gingkophyta 3-Gnetophyta 4-Coniferophyta 5-Anthophyta ```

Question 26

Seed plants

Answer 26

seed and pollen

Question 27

Seed

Answer 27

- embryo, nutrition, seed coat | - develops from ovule

Question 28

ovule

Answer 28

Novel structure appearing in seed plants Site of meiosis for female Contains female gametophyte, female sex organs, egg and embryo The megasporangium, megaspore, and their integument(s) Inside each ovule, a female gametophyte develops from a megaspore and produces one or more eggs

Question 29

Integument

Answer 29

A layer of sporophyte tissue that envelops and protects the megasporangium

Question 30

Ovule development

Answer 30

a) Unfertilized ovule The micropyle: the only opening through the integument, allows entry of a pollen grain b) Fertilized ovule A megaspore develops into a female gametophyte, which produces an egg The pollen grain, which has entered through the micropyle, contains a male gametophyte The male gametophyte develops a pollen tube that discharges sperm, therefore fertilizing the egg c) Gymnosperm seed Fertilization initiates the transformation of the ovule into a seed Consists of a sporophyte embryo, a food supply, and a protective seed coat The megasporangium dries out and collapses Contains multiple generations Seed coat: Parental Sporophyte generation -Female gametophyte: Haploid generation - New zygote: 3rd generation Female gametophyte- bagged lunch Seed nourishes young offspring with haploid gametophyte tissue

Question 31

Pollen

Answer 31

IS NOT SPERM Is the male gametophyte in seed plants Contains sperm Seed plants only develop if ovule is fertilized

Question 32

The conifers

Answer 32

-division coniferophyta -550 species -reproductive organs in cones: both male(pollen)and female (egg) Naked seeds “gymnosperms”: seed sits there as an ovule, nothing else around it Seed: embryo nourished by megagametophyte Slow reproduction (see jack pine) Sporophyte dominant Heterosporous Microgametophyte= pollen Megagametophyte -Within ovule -Makes egg and then nourishes embryo

Question 33

Life cycle of conifer

Answer 33

1. Each conifer tree has both male and female cones 2. Male cones make diploid microsporocytes (before meiosis) in microsporangium. Microsporocytes divide by meiosis, producing haploid microspores. Microspores develops into a pollen grain: a male gametophyte enclosed within the pollen wall, spread by the wind 3. A female cone projection has two ovules, each containing a megasporangium: Megasporocyte undergoes meiosis, produces 4 haploid products, only 1 survives which is called the megaspore 4. The megaspore develops into a female gametophyte by mitosis that contains one, two or three archegonia, each which will form an egg 4. Pollen forms pollen tube that digests its way through the megasporangium 7. Fertilization occurs when sperm and egg unite 8. Fertilization usually occurs more than a year after pollination. The ovule becomes a seed, consisting of an embryo, food supply and seed coat

Question 34

Megagametophyte in conifers

Answer 34

Makes egg in archegonium | Nourishes embryo

Question 35

Microgametophyte in conifers

Answer 35

-pollen grain, makes sperm