Wednesday, May 17, 2006


Hi Everyone

Please DO NOT repost your assignments - you must just edit them using your Blogger account.

Please DO NOT POST FOR OTHER PEOPLE, it is important to learn to do things yourself.

We do not unfortunately, have the resources to remark , but thank you for editing them after being assessed. This is very good practise.

Please use the time-table to check what is to be done each day.

There is a test for the Pretoria Learners next Wednesday 24th May covering Chapters 1, 3, and 4.

The Cape Town students did projects rather than tests due to having more time (the video reviews) I will put these up like I did for the Scientific Methods course so the Pretoria students can also enjoy these.

I noted that there was still problems with referencing using the CSE style. Here is tip when using Wikipedia you can use the Cite this from the left hand side menu under toolbox, this will take you to a webpage with all the various reference style, and quite obviously you scroll down to the CSE/CBE style. Now here is one time that you shoud copy and paste since there are many errors to be made in the referencing and hyperlinking, a very consistent one is to say UCT rather than UTC which stands for Coordinated Universal Time and "is a high-precision atomic time standard which approximately tracks Universal Time (UT). It is the basis for legal civil time all over the Earth"[1] .



Dr Richard Knight
Co-ordinator: National Information Society Learnerships - Ecological Informatics
Department of Biodiversity and Conservation Biology
University of the Western Cape
Private Bag X17
Bellville 7535
Phone 27 + 21 + 959 3940
Fax 27 + 21 + 959 1237



Image Reference:

Anon [Internet] Tierisch; 2006 May 17, 01:23 UTC [cited 2006 May 17]. Available from:


[1] Wikipedia contributors. Coordinated Universal Time [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 15, 09:45 UTC [cited 2006 May 17]. Available from:


All aquatic species, mostly marine evolved some 40-50 million years ago from terrestrial tetrapod ancestors during some past ten to twelve million years. “All living whales lack hind limbs and have forelimbs modified as flippers. Their limbed ancestors such as the Eocene Ambulocetus natans use paraxial locomotion powered by limbs (1). When these species are inside the water, locomotion is facilitated by a combination of tail undulation and paddling, which use the pelvic limbs. But now modern cetaceans use oscillatory locomotion. Aquatic mammals depend much less on vision and olfactory senses than terrestrial mammals”. A major selective pressure during the transition to the aquatic environment was adaptation to underwater hearing.

Some species such as whales, dolphins and others use acoustics for communication, orientation and detecting, recognizing and localizing companions, competitors, mates, predators and prey. The external ears have been lost and thus reducing hydrodynamic resistance during swimming. Different approaches from paleontology looking on morphology, development, genetics and molecular biology has tried seek an integrated explanation for whether highly specialized phenotypes such as vertebrates that are not closely related, could result from similar genetic or developmental mechanisms. The origin and evolution of whales was addressed concerning the series of morphological changes that facilitates the progressive reduction and ultimate loss of hind limbs (2).

Genetic evaluation was done on limb loss in snakes and to leg-less lizards, to see whether similar mechanisms which have driven the loss of hind limbs in whales could have been used. Also to see to which degree has such mechanisms diverged in the evolution of similar evolutionary trends shown by limb loss. “Limb loss and concurrent morphological and physiological changes are associated with the transition from land to water is discussed within the context of the current whale phylogeny. This is mostly emphasized concerning the fore and hind limb development, how the fore limbs are transformed into flippers and how the hind limbs are regressed leaving no elements or vestigial skeletal elements. Hind limbs started regressing after the ancestor of whales entered the aquatic environment” (1). Elongation of the body during transition from land to water causes the loss of hind limbs.

In most snakes limbliness was associated with adoption of new lifestyle and was driven by developmental changes associated with elongation of the body. “Adaptation to burrowing between the parallel reflect structural and functional changes associated with the switch of locomotion to axial. However, selective pressures acting on a wide range of developmental processes and adult traits other than the limbs could have driven the loss of hind limbs in whales. All limbs less tetrapod are descended from limbed ancestors”(1). Most possess limb buds at some stage during their development. Limbless ness represents arrest of limb bud development rather than absence of limb initiation or regression of a fully formed limb.


1. Andrews, R. C. 1921. A remarkable case of external hind limb in a hump-back whale. [Internet] 2006 May 10; 08:47 UTC [Cited 2006 05 10] Available from:

2. Clark, A.J. 2005. Getting a Leg Up on Land. [Internet] 2006 May 10; 10:25 UTC [ Cited 2006 May 10] Available From:
[ , accessed on 10/05/2006, 12:30].

Dianah Nangammbi
Cilla CSIR
P.O Box 395
Tel: +27 12 841 2133
Cell: +27 73 121 3589


Water vascular system is a" system made by many canals branching througthout the body that branch into many section known as the tube feet" (1). Species such as star fish and sea urchins use water vascular system to move from one place to another and they also use this system to feed themselves. Star fish and sea urchins use water vascular system to obtain energy by reacting oxygen with glucose so to give water a carbon dioxide and ATP" (Adenosine triphosphate) (1).

Water vascular system use cilia and ampullae to make things move and “Ionic imbalances allow water to pass through the madreporite and inter into the waver vascular system. Some of the water directed to the coelon and where there is a circulated of the water beating by cilia. Echinordata stretch their muscle that allows water to pass through in to the tube feet and this can cause them to expand to the ground and it can also allow the feet to retract. Echinodermata is divided the different classes namely: Asteroidea, Echinodermata, Holothuroidea, Opiuroroidea and Echinodea” (1).

Star fishes are marine invertebrate species that belong to the class Astreroidea. “These species are closely related to the brittle stars. These species found at the bottom of the ocean or sea and they feed themselves on other organisms found in water, so they use water vascular system to feed themselves. Star fishes species do not have back bone and they use water vascular system which are found on the ventral face of the sea fish’s arm and this mean that this system help them to swim or to move from one place to another” (1).

Star fishes have eyes at “the end of each arms which is able to see in dark and light places which can be useful in sensing movement" (1). Their mouth is found on the undersurface while their anus is found top. Medreporite is found on the aboral surface and it act as a water filter and it supplies water vascular of the star fish with the water to make it move from one place to another” (1). Some of these species have five arms and some have more.

Sea daisies species belong to the class Echinoderms. Its “water vascular system is dotted with the tube feet at the edge of the disk. They also have five ambulacra areas and they nutrition through the membrane from their body because they do not have mouth as well as arms. They also have two circummoral canals and peripheral ring of podia” (2). Sea lilies species belong to the class Crinoidea and they are found in low water at the bottom of the ocean about 6000 meters depth. Their mouth is” situated on top of the surface and surrounded by their feeding arms and they have stem which is used to attach themselves” (3).

Sea urchins belong to the class Echinodea which are found in the ocean. They have “five fold symmetry which helps them to move from one place to another using the tube feet” (4). They do not have eyes and the legs but they use tube feet to move, they depend on the algae for their survival (4). Sae cucumber species belong to the class Holothuroidea and they are found at the bottom of the sea. They depend on “the debris for their survival, so they can get food only when they are at the place where the food flow by with their tentacle when they open their mouth and sift through mouth while eating, and they breathe through their bottom” (5).

The last species are Brittle stars which belong to the class Ophiuroidea. They have five arms which are flexible and they can "redevelop lost of arms " (6) and they use them to run away from their enemy. “The vessels of water vascular system end into tube feet” (6). All Echinodermata have complex nervous system which are found at their skin and they are “sensitive to touch, light, temperature and status of water around them” (4). They can also dwell in brackish water.


1. Wikipedia contributors. Sea star [internet] wikipedia, The Free Encyclopaedia, 2006 May 07, 12:55 UTC [Cited 2006 May17, 12;00]. Available from:

2. Wikipedia contributors. Sea daisy [Internet] wikipedia, The Free Encyclopaedia, 2006 May 8, 12:13 UTC. [Cited, 2006 May 07, 10:54] Available from:

3. Wikipedia contributors. Crinoidea [internet] wikipedia, The Free Encyclopaedia, 2006 May 8, 12:13 UTC. [Cited 2006 May 04, 18:14]. Available from:

4. Wikipedia contributors. Sea urchin [internet] wikipedia, The Free Encyclopaedia, 2006 May 06, 22:19 UTC. [Cited May 2006, 13 45] Available from:

5. Wikipedia contributors. Sea cucumber [internet] wikipedia, The Free Encyclopaedia, 2006 May 10, 12:05 UTC.[Cited May 2006, 11:50] Available from:

6. Wikipedia contributors. Brittle star [internet] wikipedia, The Free Encyclopaedia, 2006 May 22, 22:02 UTC.[Cited May 2006, 12:00]. Available from:

Lizzy Maluleke
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If you have posted the same essay more than once, I will check to be sure that both posts are yours and then mark the later one. I assume that the second post was made because you improved your essay.

Gwen Raitt

G.R. Raitt (Miss)
Content Developer
NISL Programme
University of the Western Cape
Private Bag X17


There are two types of monkeys in the world, the old world monkeys and the new world monkeys. The monkeys which are found in the continents of Africa and Central to Southern Asia, Japan and India are the old world monkeys. On the other side the monkeys which are found in the continents of both ''Central and South, North America and Mexico are said to be the new world monkeys'' (Bhattacharya, 2003). Both old and new world monkeys have the characteristics which differentiate them from each other. Some of the characteristics include the geographical distribution.

The old world monkeys live in rain forest, islands, steppes, mountains and savanna as opposed to the new world monkeys which live in tropical rain forest (Bhattacharya, 2003). New world monkeys are known as ‘’Platyrrhines and the old world monkeys are known as Catarrhines’’ (Pratt, 2004: 2). The new world monkeys possess nostrils which face down but round in shape and the old world monkeys possess nostrils which face down but narrow. When coming to the composition of the teeth, in the new world monkeys three pre-molars are found in the big monkeys while in the old world monkeys, two pre-molars are found. Even the body size of both the world monkeys are different, the body size of the old world monkeys is large, for example, Baboon.

While the body size of the new world monkeys is small. Flat nails and pads on the buttocks are also found in the old world monkeys as opposed to the new world monkeys. The canine teeth in the old world monkeys are also said to be big and sharp with the gap between the incisors and the canines while on the other side the upper canine teeth are also said to be sharp. Pratt (2004: 3) further continues by saying that the new world monkeys belong to order Platyrrhini which consists of three families and sixteenth genera. On the other side the old world monkeys belong to the order Catarrhini which consists of the two super families.

The majority of the Catarrhines are terrestrial, which means that they live on land as opposed to Platyrrhines which are thought to be coming from the sea. The reason why the Platyrrhines are said to be coming from the ocean has been provided by the fossil remains which has been studied. On the other side the Catarrhines are said to have a ''narrow range of the niches'' (Wikipedia contributors, 2006). Catarrhines also share their niches with both the apes and the Prosimians as opposed to the Platyrrhines. It is further said that the new world monkeys are more evolutionary than the old world monkeys, which means that the world monkeys are not closely related to the modern humans as compared to the old world monkeys.

In the new world monkeys, family callitrichidae contain four genera which are saguinus like Jeffries tamarind; leontopithicus like golden lion tamarind; callantric like marmoset and the genus cebulla pygmy marmoset. In the old world monkeys the superfamily hominoidea possess small brain as opposed to the superfamily cercopithecoids which possess large brain.

In conclusion, both the old the new world monkeys show the huge differences between them which range form their geographical distribution, diagnostic features and their relationship with the modern humans. Finally, the old world monkeys are thought to be our close friends as opposed to the new world monkeys.


Bhattacharya, S. 2003. Colour vision ended human pheromone. [Online]. Available from: [cited 25 May 2006, 8:19]

Pratt, D. 2004. Humans Origins. [Online]. Available from: [2004, February 13, 9:24]

Wikipedia contributors. Monkeys [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 12, 11:33 UTC [cited 2006 May 12, 15:15]. Available from:

Peter Muvhali
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