Lecture 15 & 16 Seed Plants, Angiosperms Flashcards
what is the one phylum in angiosperms?
anthophyta - includes smallest and tallest seed plants
what is the angiosperm life cycle?
- AoG - sporophyte is dominant - gametophyte is reduced in size / microscopic and depend on the sporophytes for nutrients
what are the the “three Fs” of the angiosperm life cycle?
- Flowers - double Fertilization - Fruits
what are flowers?
- specialized reproductive shoots of angiosperm sporophytes
how do flowers attatch to the stem?
- via receptacle
what are the four floral organs?
- sepals + petals + stamens + carpels
what are the four reproductive floral organs?
- stamens and carpels (sepals and petals are sterile)
what are stamen?
- microsporophyll that consist of stalk / filaments topped by an anther with pollen sacs that produce pollen
what are carpels?
- megasporophyll that consist of ovary at the base and style leading up to stigma where pollen is received
what are incomplete/complete flowers?
- complete have all 4 organs - incomplete lack one or more
what are clusters of flowers called?
- inflorescences - ex: sunflower
what is the development of male gametophytes in angiosperms?
- pollen grain is 2-celled male gametophyte and spore wall - pollen develops from microspores within the microsporangia (pollen sacs) of anthers - each microspore undergoes mitosis to produce two-celled gametophytes: generative cell (sperm) + tube cell (pollen tube)
what is the development of female gametophytes in angiosperms?
- female gametophyte or embryo sac develops within ovule contained within ovary at stigma base - within an ovule, two integuments surround megasporangium - one cell in megasporangium undergoes meiosis - 4 megaspores but only one survives - megaspore divides producing 7-celled fem gametophyte (gymno have ~3k) - large central cell has 2 nuclei POLAR NUCLEI
what is STEP 1 of angiosperm life cycle?
FLOWERS - POLLINATION - pollen grain produces pollen tube - generative cell undergoes MITOSIS to produce two sperm cells - pollen tube grows into ovary and discharges two sperm cells
what is STEP 2 of angiosperm life cycle?
- DOUBLE FERTILIZATION - pollen tube discharges two sperm into embryo sac within ovule - one sperm fertilizes egg –> zygote (2n) - other sperm consumes with polar nuclei giving rise to the TRIPLOID (3n) food storing ENDOSPERM – nourishes developing embryo
what is STEP 3 of angiosperm life cycle?
FRUIT - SEED DEVELOPMENT - each ovule develops into a seed - ovary develops into a fruit enclosing the seed
what does the triploid endosperm do?
- nutrients for embryo - repeatedly undergoes mitosis to produce starchy food for embryo - in most monocots and some eudicots, stores nutrients - in other eudicots food reserves of endosperm exported to cotyledons
what is embryo development?
- first mitotic division - splits egg into basal and terminal cell - basal cell produces multicellular suspensor which anchors embryo to parent plant - terminal cell gives rise to most of embryo - cotyledons form & embryo elongates
what are 2 types of fruit?
- dry or fleshy
what are the three classifications of fruit based on their development?
- aggregate: single flower with multiple separate carpels ex raspberry - simple: singer or several fused carpels ex peas - multiple: group of flowers called an inflorescence ex: pineapple
what is an accessory fruit?
- contains other floral parts in addition to ovaries?
what do fruits develop from?
the ovary
what are the the four adaptive advantages to angiosperm style fertilization?
- food store for seed (endosperm) develops only after fertilization – double fertilization 2. Fruit development is usually triggered by fertilization 3. Female gametophyte is reduced in size and hence cheaper to produce 4. Production of the small female gametophyte takes few days rather than a few months – annual plants
what are 6 differences between monocots and eudicots?

what is the structure of the mature seed?
- embryo is inclosed by hard protective seed coat
why does the seed undergo a state of dormancy?
- increases chances that germination will occur at a time and place most advantagous to seedling
- sometimes requires environmental cues to break dormancy
what is a difference between monocots and eudicots?
- M: one cot + large endosperm
- E: 2 cots at embryonic axis
what is a common type of asexual reproduction in angiosperms?
fragmentation
- separation of parent plant into parts that develop into whole plants
what are the two kinds of flowers (ecious)
- monoecious: M and F flowers on same individual plant
- dioeciuos: M and F flowers on individual plants
what are 3 mechanisms that prevent self-fertilization?
- dioecous species
- stamens and carpels mature at different times
- self-incompatibility - rejects its own pollen triggering signal transduction pathway leading to a block in pollen tube growth