1. Challenges on Land Water – Most found under the surface of the land
Minerals –
Under land surfaces
Gases –
Abundant in the atmosphere
Support –
Necessary on land
Light –
More available on land

2. Temperature –
Changes are more extreme on land
Reproduction –
If gametes swim, this is a challenge on land
Dispersal –
Water is seldom available for dispersal, other methods must be explored.

3. Solutions: Getting Water: Diffusion, rhizoids, roots
Transporting water:
Xylem (vascular tissue cells)
Transporting food:
Phloem (vascular tissue cells)
Preventing desiccation:
Waxy cuticle
Obtaining gases:
Stomata or air pores

4. Obtaining sunlight:
Leaves
Supporting the Body:
Xylem
Environmental response to stimuli:
Hormones
Fertilization without water:
Pollen
Dispersal:
Movement from airborne spores to seeds

5. Plant Characteristics
What distinguishes plants?
Multiellular eukaryotes
Photoautotrophs
Live on land
Possess apical meristems in roots and shoots
Embryophytes with placental transfer cells
What characteristics do plants share with their green algal ancestors?
Chloroplasts with chla, chlb and caretonoids
Cellulose cell wall structure
Food stored as starch

6. Why was a new mode of reproduction necessary?
Disperse gametes in non-aquatic environment, on land
Gametes are produced within gametangia
Zygote develops into embryo within female gametangia. (embryophytes)
Male gametangia = antheridia -> anthers
Female gametangia = archegonia -> ovules
Gametangia are protetive jacket of sterile cells that prevent gametes from drying out.

7. Other Adaptations Waxy cuticle – prevents dessication
Stomata for gas exchange
Xylem and phloem in tracheophytes
Secondary compounds:
Flavonoids
Terpenes
Tannins
Have bitter taste, protect plant from UV radiation, protect plant from pathogens

9. Heteroorphic – sporophyte and gametophyte have different morphologies

10. Spore Production Sporangium found on sporophyte contains…
Spore mother cell
Spore mother cell undergoes meiosis …
Produces spores (haploid)
Spores with sporopollenin (durable outer coating) is unique to plants

11. Move Onto Land:
What evidence is there that plants evolved from green algae (charophytes)?
Homologous chloroplasts with chla, chlb and caretonoids
Biochemical similarities:Cellulose cell wall structure
Food stored as starch
Similar cell plate formation
Similar sperm structure
Similar genes and rRNA’s
Green algae and plants of today both evolved from a common charophyte ancestor.

12. Adaptations to shallow water
Charophycean algae live in shallow waters
If waters dry out natural selection favors land adaptations
Evolutionary novelties opened up land as an adaptive zones

13. Advantages to Land Lots of room Lots of light and gasses
Soil rich in nutrients
Originally no herbivores on land

14. Thallus of charophyte is haploid
Most algae fertilize gametes in water, this one has fertilization attached to female parent.
Non-reproductive cells of the thallus grow around zygote, and zygote undergoes meiosis after it gets larger, and isreleased and grows into haploid swimmng spores.
If meiosis is delayed and mitosis of 2n aygote occurs there is a multicellular diploid stage attached to haploid parent.
Rudimentary sporophyte would depend on the gametophyte for nourishment and protection.
Advantage to this lifecycle is that multicellular diploid can make more spores.
If protection of gametes occurred then leading to the brypohytes

15. Possible Taxonomic Differences

23. Sporophyte moss

24. antheridia
sperm
antheridia

27. archegonium
egg

29. Ferns To what division do ferns belong? Pterophyta
What evolutionary novelty is seen in these plants?
Vascualr system,with xylem, phloem and lignin
What adaptive zone opens up?
Getting taller

30. Homosporous vs. Heterosporous Vascular plants
Homosporous – sporophyte produces single spore type -> bisexual gametophyte -> eggs and sperm
Heterosporous – sporophyte produces different male and female spores that produce male and female gametophytes -> male releases sperm and female releases eggs
Which type of plant is the fern?
Fern is homosporous,

37. Fern sori with sporangium

38. Fern Frond xs with sorrus , sporangia and spores
Fern sorus with sporangia