Transcript Plant Diversity

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
Define:
Alternation of Generations
archegonium
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: