Reproduction methods

Reproduction methods

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses

The following are patterns that scientists have observed about reproduction in some animals:
 

  • Oysters release millions of eggs and sperm into the water and fertilisation occurs in the sea.
  • The female mallard duck makes a nest and lays 9-11 fertilised eggs in it.
  • The female elephant is usually pregnant for 22 months, and then gives birth to a single calf.

a)

Why do oysters release such large numbers of eggs?

______________________________________________________________________

 
b)
What is the advantage of having the elephant calf develop inside the mother before being born?

______________________________________________________________________

 
c)
Why do many birds, like the mallard duck, lay eggs in groups?

______________________________________________________________________

 
d) In which of the above animals does external fertilisation of the egg occur?

______________________________________________________________________

 

Task administration: 
This task can be completed with pencil and paper.
Level:
5
Curriculum info: 
Science, Understanding about science, Living World
Keywords: 
Life processes, reproduction, survival
Description of task: 
Notes on reproduction in some animals have been provided, and students are asked to give reasons for the different processes.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Use evidence
This resource provides opportunities to discuss using evidence/data provided by scientists to support explanations/inferences about animals' life styles.
 
Science capabilities: 
Use evidence
Answers/responses: 

 

Y10 (06/2001)

a)

Any 1 of: 

  • Large numbers of eggs and sperm are released so that the chance of fertilisation is increased because of large numbers.
  • The more eggs that are fertilised, the greater the chance of some becoming adults, or reverse of, e.g., because many eggs are eaten.

easy

b)

Any 1 of: 

  • Safer for the calf.
  • It is born in a more advanced state so there is a better chance of it surviving.

moderate

c)

Any 1 of: 

  • Eggs in a nest are vulnerable to predators. By having a number of eggs some may escape predation and reach hatching stage.
  • The chance of a baby duck surviving to an adult isn't as good as for a mammal, so having a larger number hatch may ensure some reach adulthood.

moderate

d)

oyster

very easy

NOTE: Questions a) to c) all relate to the chance of reaching adulthood. The greater the chance of this happening, the fewer eggs laid/released.