Everything Life Sciences Grade 10

variables that were tested. If your original hypothesis does not match up with the final results

of your experiment, do not change the hypothesis. Instead, try and explain what might have

been wrong with your original hypothesis. What information did you not have originally that

cause you to be wrong in your prediction.

• Example: after conducting your experiment you may have found that tomato plants that
  received more sunlight grew larger than tomato plants grown in the shade or without
  light. Therefore you might conclude your investigation with the following:
  
  
  • It was clear that tomato plants form bigger tomatoes when they are exposed to
    bright sunlight. The original hypothesis was supported.
  
  
  
  

Important principles and relationships in Life Sciences DUMMY

Surface area and volume

Depending on the system it is advantageous to either have a large surface to volume ratio or

a small surface to volume ratio

This is highlighted in the following examples:

• Flatworms and leeches have more surface area to volume to increase the area for
  diffusion for nutrients and respiratory gases across their whole bodies.


• In animals the shapes of organs are defined by surface area to volume requirements.
  For example, in the lungs there are many branches to increase the surface area through
  which gases can be exchanged.


• Cells with a greater volume compared to surface area are able to metabolise more and
  ingest and excrete more through the membrane.

Structure and function

In living organisms, the structure of a particular biological feature is related to what function

it performs. Thus for all the structures you will study in Life Sciences, the important questions

to ask are the following:

1. What makes this structure suited to its function?


2. How has the structure adapted to its function?


3. Why is this structure so efficient for its function?

1.5 Biological drawings and diagrams

Drawings and diagrams are an essential part of communication in science, and especially

Life Sciences. Remember it is not an artwork or sketch! But rather it is a clear representation

of what you observe which can be used to interpret what you saw.

Some rules to follow

Drawings and diagrams must:

12 1.5. Biological drawings and diagrams