B13 - Reproduction (Y11 Spring 1) Flashcards
🟢 What way does Sexual Reproduction work and what does it result in?
It works with 2 different sex cells meeting and fusing with each other.
This is called sexual reproduction and results in Genetic Diversity
🟢 What way does Asexual Reproduction work and what makes it Asexual
It works by one parent undergoing a type of cell division which produces genetically identical cells in the new organism.
Since sex cells are not involved this is called asexual reproduction.
🟢 How are Gametes formed?
Gametes are formed through Meiosis, where sperm (male gamete) is formed in the testes and eggs (female gametes) are formed in the ovary.
🟢 How are Genes are Characteristics passed on in Asexual Reproduction?
In asexual reproduction, offspring have all the same genes and characteristics as the one parent.
🟢 How are Genes are Characteristics passed on in Sexual Reproduction?
In sexual reproduction, offspring have a mixture of genes and characteristics from two parents or two gametes.
🟢 What is Reproduction and What are the Two Types
During reproduction, genetic information in the chromosomes is passed on from parents to their offspring. There are two different ways of reproducing - asexual reproduction, and sexual reproduction.
🟢 What is Asexual Reproduction And What Happens In It
Asexual reproduction only involves one parent. The cells divide by mitosis. There is no joining (fusion) of special sex cells (gametes) and so there is no mixing of genetic information. As a result, there is no variation in the offspring. Asexual reproduction gives rise to genetically identical offspring known as clones. Their genetic material is identical both to the parent and to each other. Only mitosis is involved in asexual reproduction.
🟢 What Organisms/Things Use Asexual Reproduction
Asexual reproduction is very common in the smallest animals and plants, and in fungi and bacteria. Also many larger plants like daffodils, stawberries, and brambles reproduce asexually. The cells of our bodies also reproduce asexually, as they divide into two identical cells for growth and to replace worn out cells.
🟢 What is Sexual Reproduction And What Happens In It
Sexual reproduction involves a male sex cell and a female sex cell from two parents. These two gametes fuse together to form a zygote which goes on to develop a new individual. Gametes are formed in a special form of cell divison called meiosis.
🟢 How Does Asexual Reproduction Result In Variation
The offspring that result from sexual reproduction inherit genetic information from both parents. They will have some characteristics from both parents. They will have some characteristics from both paremts, but won’t be identical to either of them. This introduces variation. The offspring of sexual reproduction show much more variation than the offspring from asexual reproduction.
🟢 What Organisms Use Sexual Reproduction (What Gametes are used in Plants and Animals)
Sexual reproduction involves the joining (fusion) of male and female gametes:
- sperm and egg cells in animals
- pollen and egg cells in flowering plants
❌ Advantages of Asexual Reproduction
- If a parent has desirable charactristics, they are passed on to the offspring
- It’s quicker than sexual reproduction
- No mates are needed to reproduce
❌ Disadvantages of Asexual Reproduction
- There is no genetic diversity, therefore single strains are more susceptible to the same diseases
- If there are too many indentical offspring, then they will compete against each other
- If the parent has undesirable characteristics, those are also passed on
❌ Advantages of Taking Cuttings:
- It’s quick
- It’s cheap
- It’s easy
- It’s rapid (you can make many new plants)
❌ *What Things Can Be Done With Asexual Reproduction
In asexual reproduction, it can:
- inlcude cloning
- include natural clones
- involve mitosis
- taking a tissue culture (taking cuttings)
❌ Advantages Of Sexual Reproduction
- Produces variation in the offspring (key to the long-term survival of a species)
- If the environment changes variation gives a survival advantage by natural selection
- Natural selection can be speeded up by humans in selective breeding to increase food production.
❌ Disadvantages Of Sexual Reproduction
- Desirable characteristics from a parent will not always be passed on
- A mate is needed to reproduce
- It can be risky as it relies on two gametes fusing and can take longer for a species to reproduce as a result.
🟢 What Is Meiosis/What Does Meiosis Result In (What Are Male+Female Gametes)
Meiosis results in sex cells called gametes, which have only half the original number of chromosomes. Female gametes are egg cells/ova which are made in the ovaries. The male gametes are sperm and are made in the tested.
Each gamete has 23 chromosomes, so when they combine, a full 46 chromosomes needed for a human a made.
🟢 What Happens in Meisosis
Cells in reproductive organs divide by meiosis to form gametes.
When a cell divides to form gametes:
- Copies of the genetic information are made
- The cell divides twice to form four gametes, each with a single set of chromosomes
Each gamete produced is genetically different from all the others. Gametes contin random mixtures of the original chromosomes. This introduces variation.
Gametes join at fertilisation to restore the normal number of chromosomes. The new cell divides by mitosis. The number of cells increases. As the embryo develops cells differentiate.
🟢 *Full Sequence of What Happens In Meiosis
- In humans, there are 46 chromosomes (23 pairs). One chromosome in each pair comes from the mother and father. Each chromosome in the pair is equal in length.
- A copy is made of each chromosome. The original and the copy stay together.
- The chromosome pairs line up down the centre of the cell. The pair from the father matches up with the corresponding pair from the mother.
- The chromosome pairs separate and move to opposite ends of the cell (like mitotic division resulting in 23 pairs of chromosomes in each new nucleus)
- The chromosome paors now line up again in preparation for a second division.
The second division separates each original chromosome from its copy so that eqch new cell has 23 chromosomes.
The new cell that form are called gametes. - Four new Haploid cells are for ed each containing 23 chromosomes. Each sex cell (sperm/egg) has a unique set of genes.
- The sperm swims to the ovum and the head enters. The two nuclei merge to produce a fertilised efg containing 46 chromosome that can grow by mitotic division to form an embryo.
🟢 How Is More Variation Added in Fertilisation?
Gametes join at fertilisation to restore the normal number of chromosomes. The new cell divides by mitosis. The number of cells increases. As the embryo develops cells differentiate into tissue, organs, and organ systems e.c.t.
🟢 Why is there no Variation in Asexual Reproduction
In asexual reproduction, the offspring are produced as a result of mitosis from the parent cells. They contain exactly the same chromosomes and the same genes as their parents. There is no variation in the genetic material
🟢 Why is there Variation in Sexual Reproduction
In secual reproduction, the gametes are produced by meisosis in the sex organs of the paremts. This introduces variation as each gamete is different. Then, when gametes fuse, one of each pair of chromosomes, and so one of each pair of genes comes from each parent, adding more variation. The combination of genes in the new pair of chromosomes will contain different forms of the same genes (alleles) from each parent. This also helps to produce variation in the characteristics of the offspring.
🟢 What Do Fungi Reproduce Sexually and Asexually For
Many fungi reproduce asexually by spores but also reproduce sexually to give variation.