Download Asexual reproduction

Sexual Reproduction and Asexual Reproduction
Task 1: Researching the two types of reproduction
Read the information and underline or highlight three key points for each type of
reproduction.
Sexual reproduction
In humans, the male sex cells are called sperm and the female sex cells are called eggs or ova.
Sexual reproduction produces offspring that are similar to their parents, but are not identical to
them. Sexual reproduction happens when a male sex cell and a female sex cell fuse. This is called
fertilisation. Sexual reproduction allows some of the genes from each parent to mix. In this way,
sexual reproduction leads to variation (differences) in the offspring. Animals and plants can
reproduce using sexual reproduction. Plants have pollen instead of sperm.
Sexual reproduction in a plant
Sexual reproduction in a human
Asexual reproduction
Asexual reproduction only needs one parent, unlike sexual reproduction, which needs two
parents. Since there is only one parent, there is no fusion of gametes and no mixing of genetic
information. As a result, the offspring are genetically identical to the parent and to each other: in
other words, they are clones. It tends to be a faster way of reproducing than sexual reproduction.
Asexual reproduction can happen in animals, but is less common than sexual reproduction. It
happens in sea anemones, aphids and starfish, for example. In plants, it can happen in three
ways, shown below:
Asexual reproduction in animals
Asexual reproduction in plants
1. From storage organs – Some plants, like
onions, potatoes and daffodils have
underground storage organs that can form a
new plant in the next spring.
2. Runners and plantlets – Some plants grow
stems called runners which form little plantlets
growing form them which are clones of the
parent plant. The runners may die off leaving
the clone growing by itself.
Strawberry plant with runners - stems growing sideways
3. Taking cuttings – just like the experiment
we’ve done.
Task 2: Complete the sentences about reproduction
1. Offspring that is identical to their parents are produced by
…………………... reproduction. The offspring are called …………..
2. Fertilisation is………………………………………………………….. and this
happens in …………………….. reproduction.
3. …………………………….………. involves one parent, whereas
……………………………. involves a male and female parent.
4. Two ways that plants reproduce asexually are………………………
……………………………………………………………………………………….
………………………………………………………………………………………..
5. ………………………… reproduction is much more common in plants than
animals.
6. …………………………….. reproduction produces variation, which means
…………………………. in the offspring.
Task 3: Write an answer in your book to this 6 mark question
Compare and contrast sexual and asexual
reproduction.
You must use some of these words in your answer:
Science Keywords
Comparison Words
Genetically identical
Similarly
Clones
Also
Runners
However
Fertilisation
Whereas
Male and female sex cells
While
Faster
On the other hand
Fuse
Variation
Name: ____________________________
Advantages and disadvantages of sexual and asexual reproduction
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
Most organisms reproduce either by sexual or asexual reproduction. Some organisms
reproduce by both methods depending on the circumstances. One example of an animal
that does both is the hydra. A picture of a Hydra is shown below
Describe the advantages of sexual and asexual reproduction.
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(6 marks)
Marked by: _______________
Feedback:
Advantages and disadvantages of sexual and asexual reproduction
Marks awarded for this answer will be determined by the quality of the written
communication as well as the standard of the scientific response
Poor
Understandi
ng
(0 marks)
Level 1
Basic Understanding
(1-2 marks)
Developing
 Knowledge of basic
information
 Simple understanding
 The answer is poorly
organised, with almost no
specialist terms and their
use demonstrating a
general lack of
understanding of their
meaning, little or no detail
 The spelling, punctuation
and grammar are very
weak
Level 2
Clear Understanding
(3-4 marks)
Secure

Knowledge of accurate
information

Clear understanding

The answer has some
structure and organisation,
use of terms has been
attempted but not always
accurately, some detail given

There is reasonable accuracy
in spelling, punctuation,
although there may still be
some errors.
Level 3
Detailed Understanding
(5-6 marks)
Extending

Knowledge of accurate
information appropriately
contextualised

Detailed understanding
supported by relevant
evidence and examples

Answer is coherent and is in
an organised, logical
sequence, containing a wide
range of appropriate or
relevant specialist terms
used accurately

The answer shows almost
faultless spelling,
punctuation and grammar
Examples of Biology points made in the response
Advantages of sexual reproduction:
 Produces variation in the offspring
 Variation gives a survival advantage if the environment changes by natural selection
 Natural selection can be speeded up by humans in selective breeding to increase food
production.
Advantages of asexual reproduction:
 Only one parent needed
 More time and energy efficient as do not need to find a mate
 Faster than sexual reproduction
 Many identical offspring can be produced when conditions are favourable, or by humans
for research or agricultural purposes.
Total 6 marks