Origin of Plants

• Land plants came from Green Algae

• A plant is a multicellular autotroph in which the embryo develops within the female parent.

Challenges to Life on Land

• Resources– Algae - surrounding water– Plants - air and soil

• Roots – Anchor plant– Absorb water and Minerals

• Shoots – Support, photosynthesis• Leaves – Gas exchange, photosynthesis• Vascular tissue – tube shape cells that

branch through a plant – transport waters and minerals in plant

Maintaining Moisture

• Cuticle – Land plants’ waxy coating on the leaves and other aboveground parts of many plants, helping the plant body retain water.

• Stomata - are microscopic pores in the leaf's surface.

Algae Reproduction

Surrounding water ensures that released gametes and offspring do not dry out.

Also provides a means of dispersing the gametes and offspring to new locations.

Challenge

• Plants must keep from drying out in the air & must disperse.

• Adaptations:– produce their gametes in a "jacket" of

protective cells. The protective jacket surrounds a moist chamber where gametes can develop without dehydrating.

– Sperm reach the eggs by pollen grains, which are carried by wind or animals

Mosses (Bryophytes)

• Nonvascular• Lack True leaves and roots

– Have “roots” called rhizoids• Need water to reproduce

Ferns

• Vascular• Seedless (produce spores)• Need water to reproduce• Lignin

Gymnosperms

• Plant that bears seeds that are not enclosed in an ovary.

• Conifers – most common gymnosperms.

Picture 1: Why does the celery turn red?

Picture 2: What are the red dots on the celery?

Land Plants

Problem Solution(s)

cuticle

Not in water – can’t disperse

No water to hold up plant

Need to be anchored

Need to obtain water

Stomata

Mosses (Bryophytes)

• Nonvascular• Lack True leaves and roots

– Have “roots” called rhizoids• Need water to reproduce

Alternation of Generations

• Mosses have a sporophyte (spore producing) diploid stage and a gametophyte haploid stage.

antheridium

archegoniumDefine:

Alternation of Generations

Ferns (Pteridophytes)

• Vascular• Seedless (produce spores)• Need water to reproduce• Lignin

Spore producing structure found on the underside of the leaf.

Gymnosperms

• Plant that bears seeds that are not enclosed in an ovary.

• Conifers – most common gymnosperms.

Gymnosperms

• Adaptations:– Small gametophyte (haploid) generation– Pollen– Seed – (embryo + food)

Pollen

• Pollen contains cells that develop into sperm.

• Wind carries pollen from male to female cones.

• Pollen allowed sperm to reach eggs in dry environments.

• Why are mosses always small in size?

• How do the male gametes of mosses get from one plant to another to fertilize an egg?

• The ferns dominated the first forests on land. Describe two adaptations that allowed ferns to grow to tree size.

• Why are ferns still restricted to moist habitats for at least part of their life cycle?

• How are male gametes in gymnosperms transported?

• Describe how a seed is an important adaptation for land plants.

Do Now: Copy this Chart

Ferns

• The ferns dominated the first forests on land. Describe two adaptations that allowed ferns to grow to tree size.

• Why are ferns still restricted to moist habitats for at least part of their life cycle?

Gymnosperms

• How are male gametes in gymnosperms transported?

• Describe how a seed is an important adaptation for land plants.

Angiosperms

• Describe the important reproductive adaptations that characterize angiosperms.

Name:__________________

• These anchor a plant into the ground.

• Where do the spores of ferns grow?

• What do the seeds of a gymnosperm lack?

Name:_____________

• What adaptation maintains land plants moist?

• What do mosses lack?

• What do ferns need to reproduce?

Name:_____________

• A gymnosperm is:

• Ferns can grow taller than mosses because they have:

• What is a seed:

Name:_________________

• 2 problems with being a land plant:

• These are found in leaves and used for gas exchange:

• Mosses lack: