Type of Fertilization

[nigel123]

1. Which type of fertilization (self fertilization or cross fertilization) will improve genetic variability of plants? Give reasons.

2. Why do most flowering plants tend to overproduce seeds?

[Dr.Stein]

1. Cross fertilization. In cross fertilization there will be genes recombination from other resources (other plants), so it will result in increasing diversity of their offspring.

2. To have more possibilities of their offspring to survive and continue their exixtence.

[mothorc]

with some species, structure of flower make them have to self fertilization. Thus genetical variation not improve but these species still develope normally, I don't know why.example: ficus spp (flowers inside fruit)

[Poison]

Those kind of plants (the ones that adapted themselves for self-fertilization) usually are the ones which lost their pollen carriers (maybe like a kind of insect) in some step of their evolution.
The other reason might be that there is no need for a genetic variation. I mean, the plant can already survive with its present genetic material.

[MrMistery]

That is inaccurate. There is always need for genetic variation, if it is possible. An organism is never fully adapted to the environment

[mothorc]

But I think he is right
some plant don't have genetical variety, such as mangoteen. All mangoteen trees around the world have the same genetic matterial, because they derive from soma embryal (true embryal dead)

[Poison]

That is inaccurate. There is always need for genetic variation, if it is possible. An organism is never fully adapted to the environment

That's what is written in my plant bio book. Do you have another idea about that?

[MrMistery]

Of course there are a lot of self-fertilising plants on this earth: peas, vines etc... The dracil plant even has a mechanism that releases polen when it vibrates. But to say that an organism is fully adapted to the environment? That is an absolute statement. The guy who wrote that plant book of your might have known a lot of biology, but he didn't understand it.
Anyway, just think of this. Even if the plant is self-fertilising, that does not mean that there is no genetic variation going on: mutation, genic flow etc
It's just different strategies angiosperms have chosen: cross-polination or self-fertilising. It is true that one is more succesful than the other

[mothorc]

to poison: Can you give me the name of your plant book?.thank you.
it is right that we can't say self-fertilize species have not genetical variation. but these species seem very stable.

[Poison]

I don't remember the name now. I will try to find it for you. Actually the name is Plant Biology. But I don't remember the authors.

I didn't say 'fully adapted'. I said 'it can survive'.

Even if the plant is self-fertilising, that does not mean that there is no genetic variation going on: mutation, genic flow etc

That's what I tried to say actulally. I think I have misunderstood. I didn't mean there is no variation. But there is no variation caused by fertilization.