Lecture 7 - Ferns and conifers

Question 1

Liverworts, mosses, and ferns: sporophyte and gametophyte relationship

Answer 1

Liverwort: dominant gametophyte, small sporophyte grows and relies on the gametophyte

Mosses: dominant gametophyte, sporophyte can photosynthesis and is mostly (but not fully) independent

Ferns: dominant sporophyte, gametophyte is transcient (impermanent)

Question 2

Progymnosperms

Answer 2

Archaeopteris is one type of progymnosperm

It reproduced by releasing spores and had fronds like ferns but had a ring of vascular cambium (lateral growth tissue) like a tree

Question 3

Pteridospermatophyta

Answer 3

“seed-producing ferns”

The female gametophyte is kept within the plant, the male is released as pollen

At this point, the sporophyte is dominant and the gametophyte is no longer free-living

Question 4

Gymnosperms

Answer 4

Evolved from Progymnosperms, combined wood and seeds

Appeared around 320 MYa (late carboniferous)

Question 5

Cones: reproduction?

Answer 5

Contained female gamete in the cone, the male would spread to the female through the wind

Seeds would mature in the cone before being dropped onto the floor to grow

Question 6

Seeds from cones

Answer 6

Seed coat to protect the seed, nucellus (contains food supplied by mother for the seed), embryo (new sporophyte)

Question 7

Cycadophyta: type of plant, when did they appear, extant or extinct, male and female parts, key features

Answer 7

Cycads, first dominant gymnosperms

280 MYa

Mostly extant

Dioecious (both male and female cycads)

Drought tolerant, simple structure, slow wood production

Question 8

Ginkogophyta: type of plant, when did they appear, extant or extinct, male and female parts, key features

Answer 8

Came from gymnosperms

270 MYa

One extant species - Ginkgo biloba

Dioecious, deciduous

Seed wall is fleshy (like a fruit), with extensive branching

Question 9

Gnetophyta: type of plant, when did they appear, extant or extinct, male and female parts, key features

Answer 9

Came from gymnosperms

250-145 MYa

Three extant families/genera - Gnetum, Ephedera, Welwitchia

Sometimes dioecious, mostly evergreen but rarely deciduous

Share features with flowering plants

Question 10

Pinophyta: when did they appear, extinct or extant, male and female parts, key features

Answer 10

300 MYa

One extant order - Pinales

Often monoecious

Grow big and grow quickly (Bristlecone pine >5000). Trees are often woody and branched.

Question 11

Key features of conifers today

Answer 11

Stress tolerant:

Drought reistant, Cold tolerent (move water out of cells so it doesn’t damage cells when it freezes)

Used to make soft wood