Topic 12 - Angisperms Flashcards
what is anthophyta?
- the flowering plants
- anthos = flower
-phyta = plants
How many phyla do angiosperms have?
- just one
- called anthophyta
what is a flower?
- a specialized shoot with
up to 4 whorls of modified leaves
Structure of a flower bottom to up:
Bottom
- sepals (non-reproductive)
- petals (non-reproductive)
-stamen is made up of a filament and an anther it is the male part (microsporophylls)
- carpels are made up of an ovary, style and stigma, it is the female part (megasporophylls)
what makes a pollen?
- anthers
how many ovules does the ovary at the base of carpel contain?
- 1 or more ovules
What is a perfect flower?
- contains both stamens & carpels, and
therefore is complete (= perfect), in
Linnaeus’ opinion
what is an imperfect flower?
- contains either stamens or carpels
– hence an imperfect flower is either a male
(has only stamens) or a female (has only
carpels)
what can be species be with imperfect flowers?
- monoecious
- mono = one
- oikos = house
- monoecious species have male and female
flowers on same individual plant
what can species also be with imperfect flowers?
- dioecious
– male and female flowers on
different individual plants (di = two)
what are angiosperms more reliant on?
- animal pollinators
what is the role of flowers to the angiosperms?
- flowers are often modified to attract them and dispense pollen
- flowers provide food rewards for animals that visit them and that
remove or deposit pollen
-the rewards are sugary fluids (nectar) or pollen itself
What are fruits?
- they are unique to angiosperms.
– mature ovary containing seeds
– the ‘container’ part of angiosperm (angio =vessel, container
what does carpos mean?
- fruit
In angiosperms, the megagametophyte is called?
- embryo sac which contains only 7 cells
- one of these cells have 2 nuclei which is called polar nuclei
what is double fertilization?
- one sperm nucleus fuses with egg nucleus –> 2n zygote
– other sperm nucleus fuses with the 2
megagametophyte nuclei called polar nuclei
– becomes triploid endosperm
what is unique in an angiosperms?
endopserm, take nutrients from
parent gametophyte
what does the endosperm repeatedly undergo?
- mitosis to
produce starchy food source for
embryo
what is a cotyledon?
- embryonic seed leaves
- it is inside the cell.
- you can have one or two
what are common names for the subdivision of Anthophyta
into groups called Monocotyla
and Dicotyla?
- monocots
and dicots
Steps of the Angiosperm life cycle?
- In the megaspornagium of each ovule, the megasporocyte divides by meiosis, producing four megaspores. One will survive and gives rise to a female gametophyte.
- on the anther each microsporangium contains microsporocytes that divide by meiosis, producing microspores.
- The microspore develops into a pollen grain. Th generative cell of the gametophyte will divide, forming two sperms. The tube cell will produce the pollen tube.
- after pollination, two sperms are discharged in the ovule.
- double fertilization occurs. one sperm fertilizes the egg, forming a zygote. The other sperm fertilizes the central cell, forming the endosperm.
- The zygote develops into an embryo and is packaged along with food in a seed. (embryo(2n), endosperm (3n), seed coat(2n)
- when a seed germinates the embryo develops into a mature sporophyte.
what is the first undeniable fossil of angiosperm?
†Archaefructis sinensis
when did rapid diversification of angiosperms occur?
- rapid diversification of angiosperms and
decline of many gymnosperm groups
occurred in Cretaceous and early Tertiary
what did Darwin view the appearance and dominance of flowering plants as?
- Darwin viewed the seemingly sudden
appearance and rise to dominance of
flowering plants in the fossil record as an
“abominable mystery”
