Land Plants: Seedless vascular Plant Diversity

Question 1

How has the diversity of land plants changed over time?

Answer 1

90% are angiosperms today, but they are recent addition

Question 2

What are the two types of seedless- vascular plants?

Answer 2

Lycophytes, and ferns and horsetails

Question 3

How do seedless vascular plants fertilize and disperse?

Answer 3

water (sperm), and air (spores)

Question 4

compared to the Bryophytes are seedless vascular plants more or less gametophyte dominant/reliant?

Answer 4

less

Question 5

when is the first record of vascular plants?

Answer 5

roughly 425 million years ago

Question 6

What did evolution of xylem and phloem give vascular plants an advantage in?

Answer 6

size and hydration

Question 7

What was the structures of Early vascular plants?

Answer 7

small, branched repeatedly, formed sporangia at tips of branches, no leaves, and ‘root’ structures were underground stems with small hairlike extensions, had ability to synthesise lignin

Question 8

What is lignin?

Answer 8

complex organic polymer of cell walls, especially found in sclerenchyma and associatedwith xylem vessels

Question 9

What is the function of lignin?

Answer 9

provide support and rigidity: support of plant body (especially for plants of larger size

Question 10

What is a stele?

Answer 10

vascular bundles

Question 11

WHat is the protostele? describe its structure

Answer 11

the ancestral stele - vascular tissue is organized as a simple, compacted central strand; a cylindrical strand of xylem surrounded by a region of phloem

Question 12

How did the Stele (vascular bundles) evolve?

Answer 12

changes led to more peripherally arranged vascular tissues (siphonostele)

Question 13

WHat is the structure of the siphonostele?

Answer 13

the ring of vascular tissue forms a hollow cylinder filled with pith

Question 14

What is a leaf gap?

Answer 14

often on siphonosteles - interruptions in the vascular strand where leaves originate

Question 15

What species today are siphonostele stems found in?

Answer 15

most ferns and horesetails

Question 16

WHat species today is the protostele found in?

Answer 16

lycophytes, whisk ferns and in roots of most eudicots

Question 17

What is the eustele?

Answer 17

further changes from siphonostele
a system of discreet strands around a pith (eudicots) or interspersed with parenchyma tissue (monocots)

Question 18

What species today is the Eustele found in?

Answer 18

stems of seed plants (gymnosperms/angiosperms)

Question 19

What are microphylls?

Answer 19

small scale-like photosynthetic apendages with only a single vascular strand (=vein of xylem and phloem)
emerge from stems with protosteles (lycophytes)
no leaf gap

Question 20

What are megaphylls? (true leaves)

Answer 20

leaves with a complex network of veins (xylem and phloem)
emerge from stems with siphonosteles or eusteles
found in ferns and seed plants
leaf gap

Question 21

What is homospory?

Answer 21

only one type of spore produced (ancestral state)
found in most lycophytes and most ferns

Question 22

WHat is heterospory?

Answer 22

produce two types of spores (microspores, megaspores) in two types of sporangia (microsporangia, megasporangia)
found in some lycophytes, a few ferns, and the seed plants

Question 23

WHen did Giant Lycophytes exist?

Answer 23

occured roughly 400-296 million years ago

Question 24

WHat environments did Giant Lycophytes live in?

Answer 24

swampy environments alongside early seed plants

Question 25

WHy did Giant Lycophytes go extinct?

Answer 25

due to changing climates to drier conditions

Question 26

WHat happened when the GIant Lycophytes died?

Answer 26

when the trees dies they often fell into swamps and decomposed; the dead organic matter was converted to coal

Question 27

What are features of Extant Lycophytes?

Answer 27

sporangia with spores (homospores; ancestral condiotion) protostele in roots and stem microphylls

Question 28

What are the three extant lycophyte lineages?

Answer 28

lycopodium group (club mosses) Selaginella group Isoetes (quillworts)

Question 29

Where do Club Mosses live?

Answer 29

artic to tropics

Question 30

WHat is the sporophyte of club mosses?

Answer 30

rhizomes with roots; aerial branches

Question 31

What leaf atttachment type do Club mosses have?

Answer 31

microphylls on aerial stem

Question 32

WHat are the spore producing vessels in Club Mosses?

Answer 32

Homosporous (only one type of sporangium) Sporangia often located on upper surface of sporophylls (leaves bearing sporangia)

Question 33

WHere do Sellaginella live?

Answer 33

mostly tropical, wet habitats

Question 34

What are the spore producing vessels in Sellaginella?

Answer 34

Sporophylls (mega- and microsporophylls in strobili with mega- and microsporangia) Heterosporous (microspores, megaspores)

Question 35

WHere do Isoetes (quillworts) live?

Answer 35

mostly along the margins of lakes/ponds and slow-moving streams

Question 36

What makes Isoetes (quillworts) unique among living Lycophytes?

Answer 36

has a vascular cambium, indicating tree-like ancestors

Question 37

What is spore producing like in Isoetes (quillworts)?

Answer 37

Heterosporous

Question 38

What are features of horsetails?

Answer 38

occur in moist damp habitats jointed stems rough texture (silica in their epidermal cells) underground stem (= rhizome)

Question 39

How does branching and leaves work in horsetails?

Answer 39

small, scale-like leaves in whirl at node branches arise at nodes, alternate with leaves

Question 40

What does the stem cross section of a horsetail lok like?

Answer 40

hollow pith surrounded by ring of carinal canals and vascular tissue

Question 41

What is the structure of whisk ferns?

Answer 41

have photosynthetic stems without leaves and do not form roots resemble fossils of early vascular plants

Question 42

What are aquatic ferns?

Answer 42

ferns that float on the surface of the water

Question 43

WHat is a species of aquatic fern with its common use to humans?

Answer 43

Azolla - free-floating aquatic fern that has been used for centuries in Asia as a biofertilizer of rice paddies due to its symbiotic association with nitrogen-fixing cyanobacteria

Question 44

Where is a tree fern found?

Answer 44

tropical forests

Question 45

how do tree ferns grow tall?

Answer 45

10+m by producing an erect rhizome that forms the trunk trunk is supported by a fibrous mass of rhizomes that expands as the tree fern grows

Question 46

WHat are Polypod ferns also called?

Answer 46

Adder's tongue ferns

Question 47

WHat are features of Polypod or Adder's TOngue ferns?

Answer 47

simple, spoon-shaped leaves and an upright spore-bearing stalk

Question 48

What is the stele of polypod ferns?

Answer 48

protostele in rhizome siphonostele with leaf gaps in stem

Question 49

WHat does the leaf of a polypod fern look like?

Answer 49

megaphyll frond - usually compound young frond coiled - fiddlehead Rhizomes and rachis usually have hairs, scales

Question 50

Where is sporangia located in polypod fern?

Answer 50

on lower surface of frond or modified fronds

Question 51

WHat is a sorus?

Answer 51

cluster of sporangia

Question 52

WHat is Indusium?

Answer 52

outgrowth of leaf that covers sporangia in some species

Question 53

in polypod ferns describe thereproduction?

Answer 53

gametophyte bisexual antheridia is among rhizoids archegonia is near notch water is required for fertilization

Question 54

Describe a fern life cycle

Answer 54

Sperm is released when moisture is present (n) fertilization the sporophyte (2n) is initially supplie d with nutrients by the gametophyte vascular tissues allow sporophyte to grow tall and become independent Sporangia are produced on the lower surfaces of leaves under meiosis produce haploid spores (n) spores are released into air thoese that are land in a suitable site will germinate and grow into new gametophytes