What are the primary differences between algae and land plants?
algae have primitive features;
land plants have derived features
What are the primitive features of algae?
thalus (body) & holdfast
What are the derived features of land plants?
leaves, stems, roots
What were the ancestors of land plants?
Charophytes (green algae)
What is the habitat of charophytes?
What are the shared biochemical features of land plants and their ancestors (charophytes)?
enxymes that make cellulose,
peroxisomes (organelles that contain enzymes)
What are the specialized parts (“organs”) of plants that help to maintain water balance?
stomata & waxy cuticle covering
What are the specialized parts (‘organs’) of plants that help to obtain resources and what resources do they obtain?
shoots (solar energy & CO2),
roots (water & dissolved nutrients)
What were mycorrhizae crucial in?
the ability of plants to inhabit dry land
What are mycorrhizae and what do they do?
intimate mutualistic associations of plant roots and fungal hyphae;
increase the absorption of minearls and water
What does primary growth in plants accomplish?
extends the length of a plant both aboveground (shoot system) and belowground (root system)
What produces the new cells for the primary growth of the shoot system?
shoot apical meristem
What produces the new cells for the primary growth of the root system?
root apical merastem
What is secondary growth?
growth in the lateral direction (stems thicken)
What is the function of secondary growth in plants?
strength (support weight),
get leaves closer to sun
In secondary growth, what produces the new cells?
vascular combium (tissue just under the bark)
What is the outgroup in the land plant clade?
charophytes (group of green algae)
What was the order of divergence of land plants, from first to last?
1) bryophytes (e.g. mosses)
2) seedless vascular plants (e.g. ferns, horsetails)
3) gymnosperms (e.g. conifers, cycads)
4) angiosperms (flowering plants)
What some early vascular plants?
What were the first seed plants?
gymnosperms (e.g. conifers, cycads)
What is the name for flowering plants?
What is the life cycle for the basic scheme of alteration of generations, starting at fertilization?
1) fertilization –> 2N zygote
2) mitosis –> 2N sporophyte
3) growth and mitosis
4) meiosis –> spores (N)
5) mitosis –> N gametophyte (haploid)
6) mitosis –> gametes (N)
Why are bryophytes small (few cms)?
they lack vascular tissues
What are the green plant bodies of mosses?
What is the life cycle of a typical moss, starging with sperm?
1) sperm (n) released from their gametangium (gametangium containing n egg remains within gametopphyte)
2) fertilization –> zygote (2n)
3) mitosis and development –> sporophytes growing from gametophytes (n)
4) mitosis –> spore (n)
5) mitosis and development –> gametophytes (n)
6) sperm released from gametangium
What do ferns produce?
spores (NOT seeds)
Are fern plants haploid or diploid?
What are some other seedless vascular plants (“fern allies”)?
ground pine (Lycopodium), horsetails (Equisetum)
What are sporophylls?
leaves specialized for reproduction
Where are the repdocutive structures of ferns found?
on the undersides of mature leaves
How small are fern gametophytes and new sporophytes?
tiny (<1 cm)
What is a sorus?
a cluster of sporangia (structures producing and containing spores)
What is the life cycle of a fern, starting with fertilization?
1) fertilization –> zygote
2) growth… –> gametophyte + baby sporophyte
3) long-lived sporophyte (2N)
4) sori… meiosis
5) short-lived but free-living gametophyte (N)
In what plants is protection for reproduction found?
What is the sperm protected inside in seed plants?
the pollen grain
Where does the pollen tube grow out of and why?
pollen tube grows out of pollen grain;
to bring the sperm to the egg