Some fantastic jelly-fish answers

Do you think that the polyp form or the medusa form was the common stage in the cnidarian ancestor? Explain your answer.

-Ancestors must have come up with a plan where conditions were tough to avoid extinction- produce medusa
-Polyps come up with a very clever plan
-Scientifically it is more ethical to say the polyp stage is common to the ancestor cnidaria.

Compare and contrast the feeding behaviour of Hydra and Planaria.

-Hydra-hostile, Planaria-gracile
-Planaria are autotrophic
-Planaria embark on a journey for food.
-Planaria have a blood circulatory system.
-They have a blood transport system so that you can live on land.
-In conclusion the feeding behaviour has been compared and contrasted and a summary (in table form) has been made for convenience.
-The planarians outer layer is very choosy in allowing diffusion of gases.

Instead of having pluripotent cells, would it have been better for these phyla to have specialised cells or a blood transport system? Justify your answer (5 marks)

-Pluripotent cells might forget about producing sex cells
-The cells will able to focus in their function if they are for protection and wont have to sense as pluripotent cells would to know what’s wrong they just perform the function immediately after realising the problem,.

Perhaps worms are multidimensional beings...?

IT's the only explanation I can think of to account for worms occupying the eggs they hold inside them...!

Why are female round worms larger than males?


-I think it’s because the females contain A’s, so they can be able to produce a lot (female gametes have XX)
-Females need capacity to occupy the eggs they produce.
-Female roundworms carry the babies.

Read the question? NEVER!

Recently, I gave the following questions to some of my first year students. Bear in mind that all of the content had been covered in the lectures and so should not have evoked some of the bizarre responses that I received...Below each question are the correct answers and the mark allocation.

Answer the following questions.


a) Some species of fish have evolved a modified muscle which permits them to generate electrical charge. What are these cells called? (1 mark)
Electrocytes (1)


b) Suggest two characteristics of these modified muscles which allow these tissues to generate electrical charge. (2 marks)
They possess little to no sarcoplasmic reticulum (SR) (1), they occur in a stacked arrangement like electrical cells in series (1), they respond to action potentials (AP’s) by altering their membrane potential (1).


c) What functions do these electrical charges serve for the fish? (3 marks)
Defence (1), Navigation (1), Communication (1), Hunting (1).


This is what the students wrote. Apparently reading the question is entirely optional:

a) Because the ventricular system is not fully developed, they have a ventricular septum that separates the right and left ventricles.

a) Electroreceptors [not entirely retarded, but certainly not the kind of question you should be messing up...but things then plummeted downhill; the next two answers were from the same person]

b) They have sphincters that contract and expand. They have axons that stimulate hormone production

c) They allow water to enter into the body, surrounding all cells and achieving homeostatis

b) More fibres. Higher contraction.

c) They help them to survive in water and be able to live under extreme conditions.

c) O2 transport. Nutrient and waste transport. Hormonal transport.

c) Defence; clear murky water by electrolysis and thermoregulation. [Emphasis added]

Talking rubbish...?

Line from an essay on modes of excretion in worms:

‘…and when you can’t taste anything, there is nothing entirely wrong with excreting waste through your mouth.’

At least they eat light meals...

Q: Compare the dental formulae of humans and rats. What are the implications for the diets of both species?

A: It is evident that rats have no canines or premolars [because] rats do not tear flesh like humans do, because they do not have canines and premolars to assist them in doing so. Rats eat more lighter food as compared to humans.

Do you think they actually know what a rat is...?

Q: Compare the dental formulae of humans and rats. What are the implications for the diets of both species?

A: Only 2 carnivores per jaw on a rat and a diastema gab without teeth and 2 molars per side of a jaw. This suggests that rats have a limited diet (preferably meat) while human have a wide range of diets.

What's worse? Their vicious temperament, or their poor diet?

Q: When comparing the dental formulae of a rat and a human, what features indicate a difference in the diet of the two species? What do these differences suggest about the diets of both species?

A: [The rats have]…one canine on each side and three molars on each side. The rat [therefore] uses canines to rip & tear the food & the molars to grind it. The ripping and tearing is for the meat that the rat eats & the grinding is for the corn it steals from farmers. We have incisors and premolars which are used for biting & chewing, [therefore] we have a diet with softer things such as vegetables etc.

Who knew so much was at stake...

When asked to explain the activation of a protein-digesting enzyme, the student wrote the following. What they were supposed to write was something along the lines of, the enzyme is only activated in the duodenum as the pancreas doens't have any mechanisms in place to prevent self-digestion, and thus it produces the enzymes in an inactive form. This is what they actually wrote...

"…This is to ensure that it does not react with the other substance that it should not react with as prevention of self destruction."

My job is to secrete cells!

"The stomach has gastric glands which secrete chief and parietal cells."

For the record, the gastric glands are made up of chief and parietal cells. Not that it really matters, as the question was about the activation of an enzyme in the duodenum...

Digestive enzymes in the blood...?!

"Chymotrypsinogen is secreted by the pancreas and enters the duodenum via the blood stream."

Did it never occur to the student that the last thing you want is to have protein-digesting enzymes in your blood?! They would digest all your blood cells, rendering you unable to transport oxygen to your tissues and you would die.

Sex on the brain...

Did you know:

Ferns have "sexbags" called sori.

How long does a moss take to grow?

The sporophyte of a moss is raised on a stalk-like structure called a seta, which bears a capsule (which makes and releases spores).

A1: The sporophyte consists of a capsule which is usually promptly raised on a seta.
A2: Sporophyte: A stalk-like plant that takes months to grow.

Which is it????

Why poking your eyes improves vision!

When asked what properties of the eye allow for vision, some genius wrote the following:

'The eyes contain proprioreceptors which help to detect light.'

I don't even want to know what they were thinking...

On the mode of feeding in flamingos:

Flamingos introduce their beak into water, tilted upside down and move their heads from side-to-side. They use erectile tissue while feeding.

Smelly ears...?

When asked to explain how the human body maintains balance, one student produced this little gem:

'Olfactory receptors in the ear control balance.'

I, like, totally agree with you, dude...

On a worksheet where students have to descibe the symmetry of a specimen as either 'Radial' or 'Bilateral'.

The symmetry is radical.

Snibble...?

Q: What teeth of the rat are visible in the provided diagram and how many pairs of these teeth occur in the upper jaw of the rat?

A: upper front teeth: only one pair (2). *He uses it to cut off vegetables and snibble on paper or anything chewable.

That explains a lot...

Did you know...

'Nerve tissue is divided into CNS and PMS.'

Confusion reigns supreme!

Q: What features place birds in Class Aves and not Class Mammalia?

Birds have specialised pelvic muscles.
Birds have feathers, just like mammals.
They have the ability to singing in a way of calling other organisms (birds).
Birds do not bare an alive bird after reproduction.
Birds do not necessarily consist of fur or hair.
Birds give birth to their young in the form of egg shells.
The feathers of a bird act as the hands.
Since birds do not have mammary glands they can not feed their young ones.
Feathers can be regenerated if they are disturbed or broken.
Birds can fly and walk at the same time.
Birds do not give birth to live animals.
Built for flight not pedal.
They do not show any bipedalism, which is displayed by all other creatures in the class mammalia.
Although birds lay eggs, have parental care and have hair they are placed in the class Aves because they can fly (full answer for 10 marks)
They consist of a beaker used for feeding.
They consist of feathers for flying, as well covering body to prevent body temperature inside body.
Aves have beaks instead of jaws and wings are present, which is not seen in Class Mammalia (except in duck billed platypus)
They are not underwater animals.
Birds do not have tits to feed their young with milk.
The feathers are made of retina.
The class Aves include endothermic, where mammals are ectothermic.

That's gotta be a nasty surprise...!

Q: What is the sex of this rat? Name two structures visible in your specimen that support your answer.

A: Female, ovaries, horned vagina.