Vascular Plants

Question 1

Vascular plants overview

Answer 1

Efficient and effective internal transport of water and photosynthates
Lignin – strength and rigidity
Sporophyte with cuticle
Apical meristems (growth from tips) on branching sporophytes
Mycorrhizal associations with fungi help gather water and nutrients
Alternation of generations with dominant sporophyte

Question 2

Earliest known vascular plant

Answer 2

Cooksonia
Dichotomous branching
Few cm high
Sporangia at tips

Question 3

Carboniferous

Answer 3

Lycophyte trees
Giant horsetails
Ferns

Question 4

How are ferns and mosses different

Answer 4

Ferns contain tracheids
Mosses don’t

Question 5

Cross section of fern

Answer 5

Cross section through tree fern stem shows well-developed xylem and phloem in sporophyte – water and nutrients can move efficiently – but gametophyte still vulnerable

Question 6

Heterospory

Answer 6

Specialisation of spores to reflect roles of male and female gametophytes
Male and female spores produced in different sporangia
Male spores small – microspores → microgametophyte → sperm
Female spores large – megaspores → megagametophyte → egg (and support for the embryo)

Question 7

Specialisation of male spores

Answer 7

Pollen- sperm no longer needs to swim

Question 8

Specialisation of female spores

Answer 8

Protects and disperses embryo

Question 9

Pine life cycle features

Answer 9

Pollen carries sperm – wind dispersed
Pollen tube delivers sperm to egg cell
Megagametophyte becomes seed – protection and food for young embryo (or us!) and dispersal away from mother plant

Pollination depends on the wind

Question 10

Importance of conifers

Answer 10

Dominate key ecosystems such as boreal forest, temperate rain forest
Cold-adapted and dry adapted
Major economic and cultural importance

Question 11

Gymnosperms

Answer 11

Pollen and pollen tube
Seeds from exposed ovules (Gymno = naked)
Seeds have seed coat, food supply and embryo

Question 12

Lifecycle of fern - alternation of generations with independent sporophyte

Answer 12

Diploid sporophyte
Underneath fern leaves - sorus contain sporangium
Undergoes meiosis to form haploid spores
Germinate into haploid gametophyte
Antheridium - sperm
Archegonium - eggs
Fertilisation - diploid zygote —> embryo
Becomes a sporophyte

Question 13

Dominant generation

Answer 13

Sporophyte

Question 14

Why are gametophytes vulnerable

Answer 14

No cuticle
No tracheids

Question 15

Heterosporous life cycle

Answer 15

Diploid sporophyte
Strobilus (cone)
Micro- or mega- sporangium
Meiosis,—> produces microspores and megaspores
Fertilisation
Zygote 2n
Megagametophyte supports developing embryo by providing nutrients (megaspore wall)

Question 16

Micro spores

Answer 16

Male spores
Microgametophyte—> sperm

Question 17

Megaspores

Answer 17

Female spores
Megagametophyte —> egg (and support for embryo)

Question 18

Male and female cones

Answer 18

Microsporangia and megasporangia

Question 19

Male and female cones

Answer 19

Microsporangia and megasporangia

Question 20

Pine life cycle

Answer 20

Sporophyte 2n
Male and female cones
Meiosis —> microspore and megaspores
Pollen transported by wind to female gametophyte
Pollen tube (from tube cell) grows to take sperm to fertilise the egg inside the seed
Embryo 2n within seed coat

Question 21

Conifers- where are ovules

Answer 21

No ovaries
Sit on cones

Question 22

The gynosperms

Answer 22

Coniferophyta, Cycadophyta, Gnetophyta, Ginkophyta

Question 23

How many uk native conifers

Answer 23

3

Question 24

Uk native conifers

Answer 24

Scots pine
Juniper
Yew

Question 25

What limits conifers

Answer 25

Slow process Slow pollination by wind

Question 26

When is the embryo food source formed

Answer 26

Before fertilisation

Question 27

Asexual reproduction in vascular plants

Answer 27

Fragmentation – adventitious roots (cuttings) (Equisetum, Salix) Stolons: strawberry plants (Fragaria sp.) Bulbils or adventitious plantlets (Kalanchoe daigremontiana) Apomixis (Taraxacum officinale)