L12, seedless vascular plants

Question 1

what did green algae proceed to evolve into?

Answer 1

nonvascular seedless (bryophytes) –> vascular seedless –> vascular seed

Question 2

sporophytes are the … generation

Answer 2

dominant

Question 3

explain leaf evolution

Answer 3

microphylls evolved as outgrowths, known as enations. Megaphylls evolved by fusion of branch systems

Question 4

what are the characteristics of microphylls?

Answer 4

relatively small, with single strand of vascular tissue

Question 5

what are the characteristics of megaphylls?

Answer 5

blade has a complex system of branching veins

Question 6

what is a sporophyll?

Answer 6

a leaf which bears spores and can produce spores of different sexes. Can either be a microsporophyll or a megasporophyll, OR produce both types of spores on the same leaf

Question 7

clusters of sporangia are known as …

Answer 7

sori

Question 8

how do sporophytes compare to bryophytes?

Answer 8

sporophyte is not dominant in bryophytes - not even independent
no true vasculature
no true leaves
sporophytes produce spores, but no spore-bearing leaves

Question 9

what families are in the phylum Lycopodiophyta?

Answer 9

Lycopodiaceae (lycopodium), Selaginellaceae (Selaginella), Isoeteceae (Isoetes)

Question 10

what familes are in the phylum Monilophyta

Answer 10

ferns, equisetaceae

Question 11

what are seedless vascular plants often referred to as?

Answer 11

“ferns and their allies”

Question 12

Lycopodium:

Answer 12

about 400 species, mostly tropical, spirally arranged microphylls, sporophylls often arranged in a strobilus, homosporous

Question 13

life cycle of Lycopodium:

Answer 13

1. meiosis results in spores, which are released (carried by wind mostly)
2. gametophyte develops when the spore germinates, being a hermaphrodite, containing both the immature archegonium and immature antheridium
3. the immature archegonium opens and allows sperm cells to enter, causing fertilization and a zygote to form. the mature antheridium results from the sperm cells being released
4. zygote (2n) matures into a young embryo, undergoes mitosis and develops into a young sporophyte

Question 14

definition of heterosporous:

Answer 14

same strobilus producing two kinds of different spores. produces microspores (male gamete) and megaspores (female gamete)
there is a shorter transfer after development of two sets of spores

Question 15

all vascular plants are…

Answer 15

oogamous

Question 16

is the gametophyte stage long or short?

Answer 16

very short

Question 17

the entire gametophyte life-cycle occurs in the …

Answer 17

pockets of the strobilus (sporophyte)

Question 18

male gametophyte grows within …

Answer 18

microspore

Question 19

female gametophyte grows within …

Answer 19

megaspore

Question 20

at maturity, the archegonia is exposed to…

Answer 20

the exterior

Question 21

describe ferns (monilophyta)

Answer 21

second largest plant group after angiosperms, approx. 11,000 living species, approx. 75% tropical, and shows a great diversity of growth forms

Question 22

explain the characteristics of the fern lifecycle

Answer 22

homosporous, gametophyte grows much like liverworts, spores arranged in sori underneath the leaf, and there are hundreds of sporangia on a single leaf

Question 23

describe the chinese brake fern:

Answer 23

• hyperaccumulator of arsenic
  -can thrive in soil containing up to 500 mg Arsenic/kg
• 140 mg arsenic is enough to kill adult human