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non-human reproduction
asexual reproduction
Asexual reproductive organisms do not use gametes
Gametes are sex cells that have only half of the chromosomes, they are haploid.
Through asexual reproduction, genetically identical offspring is produced.
Produces identical clones, with barely any genetic variation.
Their variation is given by random mutations, not by their reproduction type.
asexual reproduction in plants
stolons
Projected extensions of the stem over the ground. They are also called runners. Both plants might share amino acids and sucrose, but it is not likely that they share raw materials (like mineral ions).
Example: Strawberries.
rhizomes
Projected extensions of the stem under de ground.
Example: Grass.
bulbs
Leaves of a plant that are modified into layers that grow into a whole new plant due to their high concentration of nutrients. The center of the bulbs is the flower.
Example: Onions, Tulips, Lilys.
corms
The stem of a plant is modified to store nutrients in layers, with a basel plate fundamental for the plant’s survival in harsh environments. The layers are called cormels.
Example: Garlic.
tubers
The roots of a plant are modified to store nutrients and are able to turn into a whole new plant.
Example: Potatoes.
can
can
can
artificial propagation
Tissue culture
Small amounts of unspecialized tissue are placed in a full of nutrients medium (such as agar).
advantages and disadvantages
advantages | disadvantages |
|---|---|
An individual can reproduce itself without a mate. | Evolution is less likely. |
The organism does not need to produce gametes, therefore it can use those resources for other organismic activities. | If the parent does not have resistance to a certain disease, the offspring do not either. |
All good traits of the parent are inherited by the offspring | Competition for resources due to proximity or a poor environment. |
As there is no dispersal, the environment in which the offspring develops is as favorable as the parent one is. | If the parent’s environment is not good, then the offspring’s one is not good either. |
Is a quick and effective reproduction type. |
sexual reproduction
chromosomes: DNA compacted as a structure, and a unit.
plant gametes:
male gametes: pollen
female gametes: ovules.
advantages and disadvantages
advantages | disadvantages |
|---|---|
More variation, evolution-prone conditions, and constant genetic exchange. | Requires more energy to find a mate. |
Reduced competition due to seed dispersal. | Growth is slower. |
Higher chance of disease resistance. |
sexual reproduction in plants
plant parts
Sepal: Leaves underneath the petals.
STAMEN: male
Filament
Anther
Pollen sacs.
CARPEL: female
Style (not always)
Ovary
Ovules (female nuclei)
Stigma
The sticky part receives pollen.
categories for plants with flowers
dioecious: some male plants, and some female plants.
monoecious: a plant with some male flowers and some female flowers.
hermaphrodite: male and female in the same flower.
order of events
Meiosis
Pollination
Fertilization
Mitosis
Seed Dispersal
Germination
fertilization
fertilization is defined as the fusion of the gametes nuclei.
gametes
female | male |
|---|---|
bigger in size | smaller in size |
less amount produced. | more amount produced. |
stationary. | mobile. |
for fertilization, when pollen interacts with the carpel (Stigma or Style), the carpel grows a pollen tube so that the pollen can reach the ovule that cannot move.
after fertilization, the diploid cell is called a zygote.
pollination
According to how the flower is pollinated, it looks different and has different adaptations
wind
animals
hummingbirds
bats
Insects
bees
butterflies
wasps
Part | Insect-pollinated | Wind-pollinated |
|---|---|---|
Petals | Work as a land platform for animals, the petals are colorful and scentful. They might be imitating insects too. | In most flowers they are absent or they are small and green. |
Nectar | Used as a resource to give to insects in exchange for pollination. Attracts animals. Is used as a symbiosis tool and it is produced in the nectaries. | Absent. |
Stamen | It is ubicated on the inside of the flower. | Long filaments and anthers hanging out of the flower. |
Stigma | Found on the inside, with a small surface area. | Found on the outside of the plant, it is feathery so that it can catch most pollen grains. |
Pollen | Less amount is produced, is sticky and picky so that it can get easily attached to the fur of the animal pollinator | More amount is produced, is very light and smooth to be carried properly. |
Bracts | Sometimes. | Absent. |
self and cross-pollination
Self-pollination | Cross-pollination |
|---|---|
Pollen comes from the same plant | pollen comes from a different plant |
Avoided with the different levels between the stamen and the carpel. | Avoided isolating animals, and covering the flower with plastic. |