Angiosperms Flashcards
Where do flowering plants bear seeds?
within an ovary (fruit)
what does the radiation of angiosperms mark?
the transition from the mesozoic to the cenozoic era
what is the name of the female reproductive part and what does it consist of?
carpel/ pistil and consists of stigma or style leading to the ovary at the base
what is the name of the male reproductive part and what does it consist of?
stamen consisting of filament and anther
what is the job of the fruit?
protecting dormant seeds and aiding in their dispersal
when did angiosperms arise?
early cretaceous
what are the 2 main clades making up 98% of angiosperms?
eudicots and monocots
how many cotyledons do monocots and eudicots have and what are they?
monocots=1
eudicots = 2
they are seed leaves
what is the difference between monocot and eudicot veins?
monocots = parallel eudicots = net
what is the difference between monocot and eudicot stomata?
monocot = in lines equal in both surfaces - good control live in drier places eudicots = scattered - not so good at controlling water balance
what is the difference between monocot and eudicot stem vasculature?
monocots = in bundles throughout stem eudicots = continuous ring near surface
where is the cambium present?
only in eudicots meaning they can grow bigger
what is the difference between monocot and eudicot roots?
monocots= fibrous eudicots = tap root - stronger
what is the difference between monocot and eudicot flower structure?
monocots = multiples of 3 parts eudicots = 4 or 5 parts
what is the difference between monocot and eudicot pollen grains?
monocots = 1 single pore eudicots = 3 pores
which seeds are better in favourable and stressful environments?
small seeds and lots of them in favourable environments and few large seeds with lots of resources in stressful environments
what are the 6 things which determine seed size?
1) size of parent
2) form of parent
3) dispersal mode
4) environment
5) predation risk
6) lifestyle
what are 3 features of island seeds so they don’t end up in the sea?
1) bigger
2) heavier
3) harder to disperse eg reduced mechanisms for wind dispersal
which are the hormones which promote and break dormancy?
auxin promotes and gibberellins break
what are the 4 advantages of seed dispersal?
1) avoid competition with kin
2) avoid interbreeding
3) exploit new habitats
4) relationships with animals and environment
what is anemochory?
dispersal by wind
what is hydrochory?
dispersal by water
what are the 3 different zoochory dispersals by animals?
1) endozoochory - in the animal
2) epizoochory - on the animals
3) synzoochory - deliberate moving of the seed
what is the equation for seed fitness?
fitness = number x survival
what is the difference between perennial and annual plants?
perennials repeat many reproductive cycles and live for more than 2 years and annuals have one big bang reproduction and then die
what is masting and why does it occur?
synchronised flowering over large areas either to increase recruitment after a fire or to over supply predators
are angiosperms heterosporous or homosporous?
heterosporous
describe the development process to form pollen
single diploid nucleus splits by meiosis to form 4 haploid nuclei which each become a pollen grain, each pollen grain splits by mitosis to form a tube cell and a generative cell
describe the development process to form embryos
single diploid nucleus splits by meiosis to form 4 haploid nuclei and one survives and splits by mitosis to form 8 haploid nuclei within 7 cells
what is the names of the 7 cells in an embryo sac and how many of each?
2 synergid cells
1 egg cell
3 antipodal cells
2 polar nuclei within 1 cell
what are the advantages and disadvantages of abiotic pollination?
advantages - not costly
disadvantages - random process
what are the advantages and disadvantages of biotic pollination?
advantages - accurate
disadvantages - very costly to make fruits
describe the process of fertilisation?
- when pollen cell meets the stigma the generative cell splits again by mitosis to form 2 sperm cells
- one pollen nucleus fuses with one egg cell
- other pollen nucleus fuses with 2 polar nuclei giving rise to endosperm
what is an endosperm?
a triploid tissue which feeds the seedling
how do plants avoid self pollination?
each plant has 2 copies of an S gene and if pollen reaches stigma with same copy of S allele the pollen tube doesn’t grow
