Reproduction in Flowering Plants Flashcards
what makes up a flower?
female - pistil, style, stigma and ovary
male - stamen, anther, filament
what is a group of flowers?
inflorescence
what is the function of sepals?
close for protection
what is double fertilisation?
pollen lands on stigma, develops into pollen tube that carrys two sperm down
- fertilises the egg
- triggers endosperm
whats special about the endosperm?
where food stored
what happens to a seed when its fully developed?
becomes dormant in a protective coat until a trigger promotes growth
what does flowering promote?
out-breeding
what is good about fruit?
physical protection, reward for seed dispersers
types of fruit?
simple
aggregate - berries
multiple - pineapples
other ways plants reproduce?
apoxmis - clonal seeds without fertilisation self-fertilisation offering nectar rewards fragmentation roots, shoots, leaves form new plants cuttings, graft
disadvantage of seeds?
seedlings vunerable
disadvantage of asexual reproduction?
local extinctions
disadvantages of sex?
good genes lost - recombination breaks them up
twice as many females
time and energy
advantages of sex?
avoids muller ratchets
creates novel gene combos
what is mullers ratchet?
absence of recombination so mutations accumulate - asexual species won’t live long without shared DNA
