Evolution of land plants

Question 1

why are land plants important?

Answer 1

almost all life on earth is land plants
fundamentally changed the environment on earth
primary producers in terrestrial food web
domestication and cultivation of plants

Question 2

what is the origin of land plants?

Answer 2

land plants started to grow on beaches to have access to large amount of water
can get nutrients from the water
downside can’t get enough sun light to photosynthesize

Question 3

what is the common ancestor of land plants

Answer 3

likely charophytes (green algae, stonewort)

Question 4

what kind of group are Charophyta?

Answer 4

paraphyletic group

Question 5

what is paraphyletic group?

Answer 5

a group that doesn’t have all of its decedents

Question 6

what is a monophyletic group?

Answer 6

a group that has all of its decedents

Question 7

Why was dryness a challenge?

Answer 7

had no control over water content and were restricted to moist areas
water was essential for reproduction

Question 8

what was the first adaptation to fight dryness?

Answer 8

the cuticle
evolved early on but still had some water loss
present in all bryophytes

Question 9

what was the problem with the cuticle?

Answer 9

prevented carbon dioxide to be taken up
solution was pores

Question 10

what was the second adaptation to fight dryness?

Answer 10

stomata
present in moss and hornworts
prevented water loss and opened when carbon dioxide is needed
selectively and actively open and close

Question 11

what are characteristics of bryophytes?

Answer 11

no vascular tissues
no roots
gametophyte (haploid) phase dominant

Question 12

what is the challenge with competition for light and gravity?

Answer 12

grow upwards to get more light for photosynthesis
competition for light, lead to selection for growth and leaves to increase photosynthetic ability

Question 13

what is the solution for competition for light and gravity?

Answer 13

lignin
makes secondary cell wall stronger and more strong and rigid
water proof barrier
resistant to decay and attack by microbes

Question 14

what are microphylls?

Answer 14

single unbranched strand of vascular
lycophytes
- club mosses and scale trees

Question 15

what is a megaphyll?

Answer 15

multiple, branched strands of vascular tissues
evolved at least twice independently
pterophytes
- ferns, horsetails and whisk ferns

Question 16

what’s the challenge pf spatial segregation and transportation of resources

Answer 16

minerals and most water is in the soil
light and carbon dioxide for photosynthesis above ground

Question 17

where does primary growth happen?

Answer 17

the apical meristems at the root and shoot tips

Question 18

what do roots and shoots provide?

Answer 18

they provide support for the plant and transportation of minerals, water and organic substances

Question 19

what is mineral transportation?

Answer 19

short distances between cells
long distances between roots and shoot parts (xylem and phloem)

Question 20

what is phloem?

Answer 20

vascular tissue which conducts sugars though the plant body

Question 21

what is xylem?

Answer 21

vascular tissue which conducts water and dissolve minerals from soil to roots to shoots

Question 22

what are mycorrhizia?

Answer 22

good at extracting nutrients from the soil and give to the plants
plants will give them sugars in return

Question 23

what are hydroids?

Answer 23

like vascular system but for moss
independently evolved (convergent evolution)
functions the same and xylem and phloem

Question 24

what are most seedless vascular plants?

Answer 24

homosporous
some are heterosporous

Question 25

what is homosporous?

Answer 25

plants produce 1 type of spore and will develop in to one type of gametophytes

Question 26

what is a gametophyte?

Answer 26

they are bisexual
can be both egg and sperm

Question 27

what is a heterosporous?

Answer 27

plants produce 2 types of spores which develop into 2 types of gametophytes

Question 28

what is endosporous development?

Answer 28

in many heterosporous plants, gametophytes produced by spores develop inside spore wall
provides protection for gametes and later for developing embryo

Question 29

what is the problem with aridity and reproduction?

Answer 29

gametophytes of bryophytes, some gymnosperms produce haploid sperm cells
impossible for sperm to reach egg in absence of water

Question 30

what’s a gymnosperm?

Answer 30

“naked” seed plants
pollen grains produced nonmotile sperm

Question 31

what is pollenation?

Answer 31

transfer of pollen to female reproductive parts

Question 32

what is the ovule?

Answer 32

sporophyte structure that produces the female gametophyte with egg
connected to sporophyte by protective tissue

Question 33

what are seeds?

Answer 33

structures from when ovule matures after fertilization through pollination (diploid)
surrounded by nutritive tissues
they have major adaptations for uncertain environments

Question 34

what are angiosperms?

Answer 34

flowering plants with covered seeds
have carpels at center that protects ovule and seeds
fruit nourishes and disperses sends
double fertilization

Question 35

what are monocots?

Answer 35

grasses, palms
parallel-veined leaves common
bundles of vascular tissue scattered in stem

Question 36

what are eudicots?

Answer 36

most fruit trees
net-vined leaves common
central core of vascular tissue in stem

Question 37

what are some angiosperm adaptations?

Answer 37

efficient transport
many have specific pollinators instead of just air currents