Reproduction Flashcards
Why is their a need for reproduction?
For continuation of species.
What are the two things organisms are designed for?
survival and reproduction
What is asexual reproduction?
It involves cell division of a single parent by mitosis to produce genetically offspring.
Why are asexual produced population unlikely to survive severe environmental changes?
Because they produce very little genetic variation.
What is sexual reproduction?
It is when 2 haploid gametes produced by meiosis, come together to produce a unique individual.
Why are sexually produced populations more likely to adapt to severe environmental changes?
Because sexual reproduction produces genetically varying offspring, some of them are likely to have adaptations to survive such environmental changes.
Explain the haploid and diploid stages of humans.
Humans spend their entire lives as a diploid organism and the only stage that is haloid is their gametes(eggs and sperms), which also unite during fertilisation to restore diploidy.
Why are bryophytes restricted to moist habitats?
due to lack of vascular bundles and the requirement for water to complete reproduction and also therefore they are very small in size and are low lying.
Why do seedlings with tiny endosperms have a low chance of survival compared to seedlings with larger endosperms?
The seedlings with tiny endosperms have a low chance of survival because they need to quickly start producing food for themselves whereas seedlings with larger endosperms have more time to establish roots and leaves before they have the need to support themselves.
What are 3 trends observed in plant evolution?
- Sexual reproduction rather than asexual.
- Diploid stages of life are dominant rather than haploid.
- Adaptations for terrestrial reproduction such as non-swimming sperm and protected embryos.
How many chromosomes do sporophytes have and give 3 examples of it.
They have 46 chromosomes and its examples are stems, leaves and roots.
How many chromosomes do gametophytes have and give 3 examples of it.
They have 23 chromosomes and examples of it are pollen, ovules, sperm and eggs.
Describe how algae reproduce?
Many small algae reproduce asexually by dividing itself in half via mitosis to produce new algae plants whereas some algae are capable of both sexual and asexual reproduction
Give three examples of algae?
- Sea grapes (Nama)
- Eucheuma (Lumi)
- Nori
What is the male and female gametophyte known as?
Male gametophyte is known as antheridia (sperm) whereas the female gametophyte is known as archegonia(eggs).
Which stage is dominant in a bryophyte?
The gametophyte, that is, most of its life is spent in haploid stage.
3 examples of bryophytes.
- mosses
- liverworts
- hornworts
Why do bryophytes grow close to each other?
To reduce water lose.
What do sperms contain, to give them water for reproduction?
They contain flagella.
Name the first vascular plant.
Ferns.
Name the first terrestrial plant.
Bryophytes
How do ferns reproduce?
They reproduce through spores as they are seedless.
What makes ferns grow taller than bryophytes?
Presence of vascular tissues.
Why are ferns found/grow in shady areas?
Because they require water for sperms to swim to the female gametes.
Which stage is dominant in ferns?
Sporophyte, meaning they spend most of their life at a diploid state.
3 examples of ferns.
- black tree fern
- Equisetum
- lycopodium
3 differences between spores and seeds.
- seeds are larger compared to spores.
- spores are haploid, seeds are diploid.
- seeds have more stored food compared to spores.
- Seeds have seed coat and are well protected from dehydration whereas spores is not much protected from dehydration.
-Spores are dispersed by mostly wind whereas seeds are dispersed by wind, water, and animals. - spores are unicellular and seeds are multicellular.
What is the dominant stage for seed plants?
Sporophyte stage.