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 = STRUCTURERED = FUNCTIONThis is all you need to do to ACHIEVE!!!

PROBLEMSQuestion 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 areaMoistureThin membraneRemember LINK these to your points!!!!!

Think SOLO!!You have one idea- E.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 PLUSThe 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.