Animal Diversity Essay
FEEDBACK
Describe briefly in one sentence..
• The reason why animals need to carry out this
biological process.
• I know this says it won’t be marked, however,
if you show no effort and write a poor
sentence it sets the examiner up thinking the
rest is going to be rubbish!!!!!
• MAKE AN EFFORT!!! It is only 1 sentence!!!!
Question 1
DESCRIBE the diversity in the adaptations of 3
different animals in relation to Gas Exchange.
This wants you to describe the structure and
function of the animal. What are the differences
in its respiratory system?
EXPLAIN the adaptations that enable it to carry out
gas exchange.
You HAVE to get the Achieved marks here!!!
You can pick up the Merit marks here!!
PROBLEMS
1. A lot of you only described the path of the air
flow, naming the structures but not
describing the structure or the function.
2. A lot of you only described the structure or
the function.
3. A lot of you went straight in to the
adaptations, completely missing out the
structure and function.
Good Points
1. Most of you seem to understand the
sequence of the parts of all the respiratory
systems.
2. Most of you have the knowledge, but just
need to learn to structure your essays better!
3. You need to read through what you have
written, looking for the structure and the
function.
FOR ACHIEVED
Follow the structure:
The Spiracles are openings in the exoskeleton,
these control the amount of oxygen entering
the tracheal system and water leaving via
evaporation. The spiracles lead to the trachea.
The Trachea is a tube that is strengthened by
chitin to prevent it from collapsing. The
trachea allows the oxygen to pass further in to
the insects body to the tracheoles.
FOR ACHIEVED cont…
The tracheoles are branching network of smaller
tubes that are not supported by chitin. These
allow the oxygen to be passed further through
the insects body and attach directly to the
cells that require oxygen for respiration.
YELLOW = STRUCTURE
RED = FUNCTION
This is all you need to do to ACHIEVE!!!
PROBLEMS
Question 2 SUCKED!!!!
• The majority of you only managed to describe
things.
• You tended to write a lot of ideas down
without actually relating them to diffusion.
• Some of you just repeated what you had
already written.
Question 2
Discuss diversity by relating the adaptations
described to each animals habitat or
environment.
Evaluating these adaptations with respect to
how they allow the animals to:
• Overcome the limitations and demands of a
particular habitat or environment and to
• Make use of the resources or opportunities
provided by that habitat.
Good Points
• You have the knowledge and the right ideas,
but you must THINK and make sure you
explain things, not just write down the basic
ideas!
Brainstorm the Q
Evaluate
• Means to give your opinion or some expert's
opinion of the truth or importance of the
concept. Tell the advantages and disadvantages.
Brainstorm each animal on the back of your exam.
What is it’s habitat? What resources has it got?
What hasn’t it got? How does it over come it?
THEN
REMEMBER you are talking about GAS
EXCHANGE!!!!
• You need to remember all of this is to relate to
Gas Exchange!
• What do you need for DIFFUSION?
Large surface area
Moisture
Thin membrane
Remember LINK these to your points!!!!!
Think SOLO!!
You have one ideaE.g. Fish have a circulatory system.
You have a few ideas.
E.g. Fish have a circulatory system this allows them
to grow to larger sizes.
They have a counter current flow which means that
it can extract the maximum amount of oxygen out
of the water.
The blood carries the oxygen around the body to
the cells.
Merit! You can link your ideas
together.
E.g. Fish have a circulatory system. The blood carries the oxygen around the
body to the cells, after gas exchange has occurred at the gill filaments and
lamellae. (Description!!!)The gill filaments and lamellae provide a large
surface for gas exchange which maximises the amount of oxygen that can
be diffused across at one point in time. The blood then transports the
oxygen to the body cells that require it to make energy through the
process of respiration(Explanation!!!)
They also have a counter current flow where water flows in the opposite
direction to the blood. (Description!!!!) This means that there is always a
high concentration gradient maintained. There will always be more oxygen
in the water than the blood ensuring diffusion will always occur and the
flow of oxygen in to the blood stream. which means that it can extract the
maximum amount of oxygen out of the water. (Explanation!!!)
Excellence..summarise, evaluate!
You relate it all together ! So what you wrote for Merit PLUS
The fact that fish have a circulatory system and efficient gas exchange
system means that the body cells do not have a limited oxygen
supply, and can always receive the oxygen they require for
respiration. This means the size of fish is not limited.
However, insects do not have a circulatory system this limits their size.
This is because insects use a tracheal system where oxygen diffuses
from the spiracles, along the trachea to the tracheoles and directly
to the muscle cells. This is only efficient over short distances.
If the insect was to be larger in size, the rate at which diffusion would
occur would be too slow, as the distance would be too great and
they would require a transport system.
Therefore, insects are limited in size by the lack of a circulatory system.