Biology Lecture Exam 2

Moss Embryo

Immature sporophyte, nurtured by gametophyte at some point

Liverworts

Has 5200 species, small and inconspicuous, Sporophyte is very tiny compared to large gametophyte

Gemma Cups

Small cuplike structures on surface of gametophytes, responsible for asexual reproduction (fragmentation)

How do plants breath

Through stomata

How do liverworts breathe

Breathe through pores that can’t open or close

Antheridia (sperm) and Archegonia (eggs)

Specialized reproductive structures, Antheridia produces sperm and Archegonia produces eggs

Elaters

Helical shaped cells that aid in spore dispersal and increase in size when damp

How much can moss absorb

Can absorb 20x it’s dry weight

What are the two types of cells in moss

Dead

Living

Dead moss cells (Hyaline cells)

Absorbs and holds water

Living moss cells

Perform photosynthesis

Why is the fossil record for bryophytes poor

Because bryophytes are soft-bodied and lack vascular tissue

Sphagnum moss spore launch

Sporophyte connected to gametophyte, dries out, pressurizes, and explosively pops open the operculum(cap) releasing spores

How fast can the sphagnum launch spores

60 mph

Who did research on plant movement

Joan Edwards

Moss Gametophyte

Helically arranged leaves, conductive tissue consists of hydroids and leptoids

What are the two types of connective tissue in moss gametophytes

Hydroids and Leptoids

Hydroid

Carry water

Leptoid

Carry sugars

How many guard cells do Moss have

1 used for the pore

Dung Moss (Splachnum Rubrum)

Moss that grows where dung is

Disjunct Distribution

Occurs when the same species is found in two or more widely separated geographic areas.

Who proposed that dung moss species was separated by birds

Lily Lewis

Why did Winona Welch study moss

She felt bad for them

Longest cryogenic suspension for plants

20 years

Longest cryogenic suspension for animals

10 years (Tardigrade)

Can you freeze bryophytes and reanimate it

Yes bryophytes have amazing regeneration capacity, an example being in Antarctica

Oldest regrowth of moss

1500 years (millennial timescale regeneration)

Amount of Liverworts species

5200

Amount of Moss species

10,000

Amount of Hornwort species

300 (least diverse bryophyte group)

Why is Hornwort Anthoceros a puzzling group

Has Photosynthetic sporophyte

Basal Meristem

Like a vascular plant

Basal Meristem

Growth tissue at the base that makes new cells

Why are hornworts considered free-living

Stomata

Photosynthesis

Basal Meristem

Why are spores in tetrads

They are in tetrads because of meiosis

Pseudo-elaters

cells in hornworts that twist as they dry, helping disperse spores, not true elaters because they develop differently

Closest bryophyte to vascular plants

Hornworts

Most seedless vascular plants are

Ferns

Characteristics of Seedless Vascular Plants

Heteromorphic AOG

Dominant Sporophyte

Xylem Phloem

Tissue Systems

Primary and Secondary Growth

How do we use seedless vascular plants everyday

We use it for energy, the 60% of coal we use is mostly seedless vascular plants

How did plants stand so tall back then

Vascular Tissue System (Xylem, Phloem)

Production of Lignin

Xylem

Moves water and minerals from roots to rest of the plant

Phloem

Moves sugars produced by photosynthesis to other parts of the plant

Why are tree fern cross sections different

For more efficient transport

Primary Growth

Comes from apical meristem, increases tree height and produces primary tissues

What type of growth does seedless vascular plants do

Primary Growth and Secondary Growth

Secondary Growth

Comes from the cambial meristem, increases stem root and diameter, produces secondary tissues and secondary xylem (wood)

Tracheids

Transport water and minerals, give plant structure and allows it to not be crushed during transport

Heterospory

Adds another layer to AOG, sporophyte produces microspores and megaspores

Microspore

Makes a male gametophyte that produces sperm

Megaspores

Makes a female gametophyte that will produce eggs

Homospory

Plant produces only one type of spore

Can seedless vascular plants be either heterospory or homospory

Yes

What happens to antheridia and female gametophyte if plant is heterosporous

Antheridia disappears, Female gametophyte is reduced

Germination

A spore or seed starts growing

Suspensor

Grows in embryo, pushes the developing embryo into nutrient-rich female gametophyte tissue, helping the embryo obtain nutrients during development.

Whisk Ferns (Psilotum)

Tiny Leaves

No Roots

Rhizome and arial stem
Very Reduced

Psilotum Gametophyte

Subterranean (underground)

Mycorrhizal relationship - Gets help with nutrients by fungi

Fiddleheads

Fern leaves that starts tightly coiled and unravels due to circinate vernation

Sori

Groups of sporangia

1/3 of Ferns are epiphytic meaning?

They grow on trees