Chapter 29: How plants colonized Land Flashcards
What are 6 traits that plants have in common with protists like algae?
- Multicellular
- Eukaryotic
- Photosynthetic
- autotrophic
- cellulose walls
- chloroplasts with chlorophylls a and b
What is the relationship between charophytes and land plants?
Charophytes are the only algae that are the closest relatives to land plants NOTE: ** LAND PLANTS DID NOT EVOLVE FROM CHAROPHYTES**
What are 4 distinctive traits that plants and charophytes share? (synapomorphy features with charophytes)
- Rings of cellulose-synthezising proteins (instead of linear in other algae)
- Peroxisome enzymes (minimize loss of organic products)
- Flagellated sperm
- Formation of Phragmoplast (wall between nuclei of two daughter cells during cell division)
What is sporopollenin and why was it useful in adaptation to terrestrial life?
sporopollenin is a layer of durable polymer that prevents exposed zygotes from drying out. It enabled plants to live above the waterline.
What are 4 benefits to moving to terrestrial life for plants billions of years ago?
- bright, unfiltered sunlight
- more co2 from atmosphere than water
- soil by the edge of water had tons of nutrients
- few herbivores and pathogens
What were 2 big challenges of terrestrial habitat living?
- Lack of water
2. Lack of structural support against gravity
what are 4 key traits that appeared in land plants and not charophyte algae? (SYMPLEISOMORPHIES OF LAND PLANTS)
- alternation of generation (including placental transfer cells and embryophytes)
- walled spores produced in sporangia (sporopollenin)
- Multicellular Gametangia (archegonia/anthridia)
- Apical Meristems
What are 2 traits (besides the ones not shared with charophytes) that helped plants adapt to terrestrial life?
- presence of a waxy cuticle to prevent water loss
2. Secondary Compounds to defend against parasites and herbivores
What are Bryophytes and what species do they include?
Bryophytes are nonvascular seedless plants, that include liverworts, mosses and hornworts.
What is the dominating form of Bryophytes?
Gametophyte form
What do bryophytes need in order for fertilization to happen?
They need to be in a moist environment because the sperm has to travel in a water medium to get to the egg
What anchors the gametophytes?
Rhizoids
What forms as a result of germinating moss spores?
Protenema –> a mass of green, branched and one-cell-thick filaments
Describe the Alternation of Generation Cycle for mosses in 10 steps
- Spores develop into protonema
- Haploid protenema produce buds
- Buds divide through mitosis and form 2 Gametangia: male and female
- The male gametophyte, contains antheridia that make sperm
- The female gametophyte, contain archegonium that produce eggs
- Sperm swims to egg
- fertilization occurs
- Zygote develops into sporophyte embryo
- Sporophyte embryo grows a long stalk that emerges from archegonium
- Sporophyte is nutritionally attached to gametophyte
- Meiosis occurs
- Haploid spores in capsule pop out and form protenema.
What is the function of foot of the moss sporophyte?
Absorbs nutrients from gametophyte
What is the Seta in the moss sporophyte?
It is a stalk that transports nutrients absorbed from the foot to capsules where spores are made
What are peristomes in moss?
They are structures that open in dry conditions to get more water and close in moist conditions to keep in more water.
What is a type of moss that is used in peat moss? Why is it beneficial?
Sphagnum is a moss found in wet lands that forms peat moss. It inhibits decay of other organisms and often preserves courses. It also can be a source of fuel because it contains 30% of the world’s soil carbon, therefore its a large co2 reservoir.
What are 6 properties of seedless vascular plants?
- flagellated sperm that needs water to reach eggs
- mainly lives in damp environments
- sporophytes are not dependent on gametophytes
- Sporophyte dominant
- Contains xylem and phloem
- Contains sporophylls –> spore bearing leaves
What is the alternation of generation cycle for ferns (in 6 steps)?
- Sporangia releases spores (spores are bisexual)
- Each gametophyte develops an archegonium (female part) and antheridium (male part)
- Sperm gets released at different times and eggs develop at different times to promote genetic diversity so other sperm can fertilize the eggs
- Sperm uses flagella to swim to eggs
- Zygote develops into a new sporophyte –> grows out of the archegonium of parent gametophyte
- On the underside of sporophyte leaves are sori which are produce spores from sporangia
How do seedless vascular plants transport their water and minerals?
Through Xylem (which is composed of dead cells) and tracheas which are tube shaped cells that carry water and minerals from roots.
What are water conducting cells strengthened by?
Lignin
What are tubes that transport sugars, amino acids and other organic products from the leaves to the rest of the plant in seedless vascular plants?
Phloem
What is the difference between microphyll leaves and megaphyll leaves?
Microphyll leaves are older and they are small and spine shaped and are supported by a single strand of vascular tissue
Megaphyll leaves are newly evolved leaves with tons of branching and a vascular system that has a greater photosynthetic productivity
How do homospores produce spores in 3 steps?
- Sporangium on sporophyll
- Produces single type of spore
- Typically bisexual gametophytes which make eggs and sperm
How do heterospores produce spores in 2 steps?
FEMALES:
- Megasporangium on megasporophyll
- Produces megaspores
- Megaspores produce female gametophyte
- Female gametophyte produces eggs
MALES:
- Microsporangium on microsporophyll
- Produces microspores
- Microspores produce male gametophyte
- Male gametophyte produces sperm
What are 2 clades of seedless vascular plants?
- Lycophytes (phylum lycophyta): include club mosses, spike mosses and quill worts
- Pterophytes (phylum pterophyta): include ferns, horsetails and whisk ferns
Whats the difference between lycophytes and pterophytes?
pterophytes are more closely related to seed plants, and have megaphyll leaves and branching roots.
Lycophytes are mostly microphyll leaves and only branch at growing up of root.
What is a significance of seedless vascular plants today?
used as coal when they’re fossilized because they store ALOT of Co2.
Which prehistoric era did seedless vascular plants dominate the earth? Why?
Carboniferous period –> because there was a lot of co2 in the atmosphere and they stored a lot of it and were able to utilize it.
What are 3 advantages of bryophytes not growing tall and being thin?
- no vascular system –> don’t have something to support their weight or resist gravity
- Get nutrients straight from the ground
- Thinness allows them to absorb from atmosphere and ground without need for a transportation system
What are 3 Economic uses for seedless vascular plants (like pterophytes and lycophytes)?
- silicon dioxide on horsetail stems (lycophytes) that are cleaning agents
- Young fern sporophytes that are called fiddleheads –> edible
- Spores produced by lycophytes were once used as flash powder in photography because they’re rich in oils
