LESSON 12- PLANT REPRODUCTION Flashcards
Types of reporduction
Sexual and Asexual
Asexual: Budding
A new individual develops from an outgrowth on the body of an organism
Hydra reproduce this way
-When the conditions are favourable the hydra grows one or more extensions on the side of their bodies
-When they are large enough, these buds detach and live as a new genetically identical individual
Asexual: Fragmentaion
a process in which a piece or body fragment of the parent organism develops into a mature individual
All fungi develop this way
-Mushrooms grow small pieces, called spores, which break off and then develop into a new genetically identical mushroom
Asexual: Mitosis
A single cell dividing into 2 indentical daughter cells
Pros of asexual reproduction:
- No seeking of mate
-Plantlets formed by asexual reproduction are more healthy tahan younge seedling produced by sexual reproduction. So plantlets have a higher survival rate
- Takes less energy because specialized reproductive structures are not formed
-If it had traits that allow it to survive certain conditoon, offspringa will have that ability too
Cons of asexual reproduction:
- 1 unfavorable conditon could mean a population wiping out because genetic info is indetical
Structures involved in Asexual reproductions
-corms
-stolons
-“eyes” on tubers
Sexual: Meiosis
- contributes to variety
-Meiosis makes gametes (sperm and egg cells)
Sexual reproduction in Angiosperms
Pollunators brush agsint anters and pick up pollen
- When pollenatar brushes pollen from another flower onta stigma, the flower is pollinated
- Next the sperm joins a egg
- Pollen grains consist of 2 types of cell tube cells and generative cells
-Pollen grain lands on stigmas, uses the tube cells to burrow down a pollen tube from the stigma through the style to the inside area of the ovary
-Generatives cell which is inside the ovary will divide into 2 sperm cells
-From there, the sperm cells target an ouvle inside the ovary
- Each ovule has the potenial to devlope into a seed if fertilzed
-inside the ovule there is an egg cell and 2 polar nuclei
-one sperm cell fertizlies the egg, which forms a zygote
-the second sperm join with the 2 polar nuclei, whic devlopes Endosperm.
-ovary ripens and turns into fruit
-seeds trvael far from parent so they do not compete
Parts involved in angiosperm sexual reprodcution
stamen, anther, filament, carpel, stigma, style
style
the stalk that leads to the ovary
stigma
the sticky surface on top of the
style
carpel
the female reproductive fl oral part,
comprising a stigma, a style, an ovary,
and an ovule
filament
the thin stalk that supports
the anther
anther
the floral organ that produces
pollen
stamen
the male reproductive fl oral part,
comprising an anther and a fi lament
pistil
female reproductive structure
Sepals
protect planst bud
Sexual reproduction in Gymnosperms:
-Pollen from males cones are released
-female cones may pick up on the pollen, the pollen fertilizes in the ovule
-This makes a seed
Sexual reporduction: non-vascular seedless
- Make egg and sperm
-sperm and egg find each other if its wet enough to swim to nearest egg
-egg fertilizes and creats sporophyte
-spores released into air and moist place
Sexual reporduction in vascular seedless plants
- spores on underside of frond. fern leaf
- spores released into wild
Pros of sexual reproduction
- adapts to a variety of envirments because of gentic variety
Cons
- sepcalized organs needed to produce the sex cells
- May require more resources
- combining gentics may make offspring weak
Gymnoseprms pollination
-wind pollination
-insect pollination
Gymnoseprms fertilization
- 1 sperm nucules fertilizes eg and diploid
-zygote is formed
Gymnosperms seed production
-zygote devlopes into embryo
-seed groes and become mature sporophyte
Angiosperms pollination
Self-pollination: Plants pollinate themselves or another flower on the same plant.
Cross-pollination: Plants receive pollen from another plant, ensuring genetic diversity.
Animal Pollination: Insects and other small animals move from flower to flower collecting nectar and moving pollen.
Wind Pollination: Some plants lack colourful reproductive organs but produce large quantities of light pollen grains to increase the chances of pollen landing on a receptive reproductive organ.
Fertlizarion in angiosperms
- When conditons are right pollen grain begins to hrow a pollen tube
- Pollen tube grows down style unti its is at ovary
- carry 2 haploid sperm nuclie to the ovary
-once pollen tube reacts ovary both sperm nuclei are involved in seperate fertilization events, called double fertilzation
- 1 sperm egg fertilizes the egg which forms zygote
-2nd sperm joins 2 polar nuclei
Seed production in angiosperms
- ovary ripens and turns into fruit
-ovary wall turns into fruit wall –> pericarp
