Biodiversity

Tuesday, May 16, 2006

THE HUNT IS ON FOR PLAGIARISM


If you have received an e-mail recently from us, it probably means that your assignment was found to have an unacceptable amount of plagiarism. Now this is what we are doing to do this time, you are getting zero for that assignment, simply because I have warned you about it. Some of you have asked for remarks, the policy as clearly stated is first offence and a rewrite restricting to 50% and second offence it is zero. For some of you this is a second offence, but since we are nice (....really) we are prepared to play the following game, it’s called Cat 'n Mouse and here is how the game is played. You are the mouse (obviously) so we are equally obviously the cats. We are not Schrödinger's cat either (best look that one up since it will appear mysteriously in your test!), we are very real and very alive and we are on the hunt for plagiarism. Unfortunately you are not the cat blessed with nine lives, you only have seven lives*. What do I mean? You should have handed in 12 (twelve) answers, we will take the 10 (ten) best of these, so it means that you can still get out of this game somewhat un-harmed (suffering only a nervous twitch or two, but this should be temporary), but you have to be quick and re-edit your assignments so there is no plagiarism before we get to them.

In our game we are marking from questions one to twelve in that order, if we find that there is sufficient evidence of plagiarism then we will leave our claw mark as a comment attached to your assignment and an email will be sent to you informing of a zero mark and no further comments will be provided, you.. see we don’t really know who the author of the material is, Wikipedia or your?. Consequently the first two lives you loose can essentially be given back to you, after that you start losing the odd appendage like a tail or a leg. Of course if you loose all four legs and a tail you are sort of history, or a basket case (you will not have passed unless we gave you 10 out of 10 for all your other un-plagiarised answers, which is really rather unlikely).

You could have avoided all of this undue stress by observing our rules, properly quote, properly reference, and write in your own words and therefore be lying back with your Martini in your hand enjoying the sunshine, or possibly and more profitably go through the other chapters. For those of you not so diligent, you now have to learn to strategize your game and get to your plagiarised answers and correct them before we get to them to mark! This is a really neat game and I am sure that it will add interest to our predators Nick and Gwen. I am not sure how far into the hunt these two are, but usually the male hunter is very quick and the female hunter very very cunning and they each have six of your questions to sniff down any plagiarism. Unfortunately you have to contend with both, with one hunting you down in questions 1, 3, 5, 7, 9 and 11 and the other hunting through the remainder of the questions.

Just in case anything is unclear, it is best that you confirm that you know the rules of this particular game by adding your acceptance as a comment to this posting. Please ALSO note that we are expecting more than just rephrasing from Wikipedia and the notes and certainly three or so references which must be correctly cited with a working URL which will be tested. Please attempt to find non-Wikipedia references. Twenty percent of your marks will be allocated to referencing and marks will be debited if the referencing is incorrect or the links do not work.

Happy Hunting


Rich



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

Email Rknight@uwc.ac.za

Web http://nisl.uwc.ac.za



*In English cat is said to have nine lives, but in other countries it has only seven lives, best live in the UK


Image Reference:

Cohen, M.E. Michael E. Cohen Cartoon Cavalcade [Internet]. 2006 May 10, 8:16 UTC [cited 2006 May 16]. Available from: http://members.aol.com/lymond/catnmouse.html

Some Reading:

Wikipedia contributors. Erwin Schrödinger [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 10, 10:16 UTC [cited 2006 May 16]. Available from: http://en.wikipedia.org/w/index.php?title=Erwin_Schr%C3%B6dinger&oldid=52466373.

REVIEW OF THE EVIDENCE WE HAVE THAT DINOSAURS WERE WARM-BLOODED

“Dinosaurs dominated the terrestrial ecosystem over 160 million years and these vertebrate animals first appearing approximately 230 million years ago” (1). They were vertebrates animals because they were characterised by back bone. Today only fossils records of the dinosaurs is the evidence that this animals once existed and they had suffered a devastating loss and they have gone extinct which ended their dominance in the land. However it is believed that "birds evolved from the dinosaurs" (1). “The earliest recorded dinosaurs fossils were found in Madagascar” (1). The dinosaurs were “slightly built and were of different diets, there were carnivores, herbivores, omnivores and others were insectivores” (1).

According to "the current studies by the scientist, it is believed that, the dinosaurs were warm blooded animals unlike the early debates that they were cold-blooded animals” (1). The "current evidence by the scientist that the dinosaurs were warm blooded animals" (2) proved seems to be true based on the available evidence. Warm-blooded animals are “animals that able to maintain thermal homeostasis, they keep their temperature at constant level in spite of the temperature of the surrounding environment” (2). The dinosaurs are able to keep their body temperature by regulating their metabolic process rates.

The “discovery of polar dinosaurs in Australia and Antarctica is also evidence that they were warm-blooded animals” (1). This is because they were able to “survive under very cooler condition” (1). This mean that their body able to maintain the body temperature for them to survive. “Their feathers may have played a role in providing regulatory insulation and the analysis carried on their blood vessels structures shows that of endortherms in dinosaurs bone” (1).

"The dinosaurs had the skeleton structure which suggested that their lifestyles were so active similar to those of endortherms we know in todays life" (1). The body size of the dinosaurs is also another factor which the scientists believed that these animals were warm-blooded. This is because the size of animal plays a role in maintaining the body temperature; animals with large body size are able to maintain their body temperature at constant level. Their body size made them to be called bulk endortherms. These “bulk endortherms are animals that are warmer than their environments through sheer size rather than through special adaptations like those of birds” (2).

It is said that “the warm-blooded animals grows faster than the cold blooded animals and the fact that the dinosaurs reach substantial size while they are still in the nests (Horner, j 1978). This was “proved through the isotope of their bones” (3).
The above evidence resulted to the conclusion that the dinosaurs were really warm-blooded animals and thus they managed to cope under cooler conditions in areas they existed using that ability as a mean of survival.

Reference:

1. Wikipedia contributors. Dinosaur [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 24, 06:00 UTC [cited 2006 May 24]. Available from:

2. Wikipedia contributors. Warm-blooded [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 9, 17:29 UTC [cited 2006 May 24]. Available from:

3. Wikipedia contributors. Jack Horner (paleontologist) [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 23, 00:29 UTC [cited 2006 May 24]. Available from: http://en.wikipedia.org/w/index.php?title=Jack_Horner_%28paleontologist%29&oldid=54622320.


Mr Lufuno Mukwevho
CSIR Pretoria
P.O. Box 395
Pretoria
0001
Tel: (012) 841 2133
Fax: 012 842 7024
Cell: 0723175626
E-mail: lmukwevho@csir.co.za
My blog URL: http://mukwevholufuno.blogspot.com/

GENERAL ADAPTATIONS BIRDS HAVE EVOLVED FOR FLIGHT

Evolution of bird from small Theropod Dinosaurs as it was suggested by paleothropologist can be the start of flight evolution.[3] This evolution of flight was sugested to be inherited from the species which was living on the ground , so as birds have already suggested that they evolve from theropod dinosaurs which was not capable of flying .it was thought by paleothropologist that they underwent modification which result in the evolution feathers. With the evolution of feathers they tend to have different mode of locomotion which is diferent to their ancestor.


Bird adapt this type of movement as a mode of locomotion,and it became a character to most of the world birds species.this adaptation help the bird to access many thing that was not close to it ,most of the bird tend to chose diet which found in the canopy of the trees and flying insects.other use this mode of locomotion to avoid predators and also the competition that can develop for feeds and habitant.having this ability they end up living in the canopy of trees for most of their time.


However; this adaptation tend to have some changes that bird have to undergo,so that they can be able to fly higher than the first bird species.They undergo modification on the limbs that was used as wing,some lose bony tails and toothed jaw which was modified by lightweight beaks.this was done to reduce the weight that the early bird have, that reduce the flying height. Sekeletal hollow that bird have enables them to fly high because it made them to weigh less.”also the fearthers are made by vanes known as barbules that close them together, allowing feathers to stretch and give birds strength to fly”[1]


This adaptaion also involve the reproduction modification for birds,reproduction change incase to alllow bird to weigh less which willl enable birds to fly.”for instance ,they keeep their reproduction organs(ovaries,testes and oviducts)for most of the year,and make them large only during breeding period”.[1] this made the bird rest in their nest during reproduction period,because they will be having more weight which cannot enable them to fly high.


This anatomicaly change influence most of birds to weigh less and have ability to fly.it also helps them to adapt different type of living,some bird are noctural,while other are not they have chance to feed during the night as they can spot their prey during the night while their pray cannot see them. This happen because the prey will be on the ground and the bird will be on top of the habitant that the prey are living in.


Flight need energy,so birds need to be warm blooded because in the atmosphere there is cold air.it will be dificult for birds top flap their wings if they cannot maintain their body temperature.[2] scientist argued by the statement that indicate bird as endothermic species which is mostly mammals,it was suggested that it inherit the process from their ancestore which was warm-blooded animal.and also some happen during modification with evolution.


These adaptation that birds have to day,was evolved during the modification from the ancestore that was suggested for bird which is Theropod Dinosaurs.it evolve as the method of modification and development,they develop this mode to access benefit that will reduce competition on resource;like food and shelter.they also use this mode to avoid predators


In general most of the species adapt different behaviour because of the environment they are living in. predators influence some species to develop different behaviour, and also diet that different species choose to feed on also introduce different behaviour on certain species. Birds avoid under ground predators by developing mode of locomotion which enable them to fly higher so that the predators cannot have access them. They also choose diet which is abundant in the higher level which is only accessible by species that can fly only to avoid competition, diet such as nectars found in the canopy of the trees and flying insects.


References:


1. Adaptations for Flight.[Internet]cited 2006-May-09, Available from: http://www.stanford.edu/group/stanfordbirds/text/essays/Adaptations.html


2. Hasting L.Your guide to animal/wild life, Birds. [Internet] cited 2006-May-09 Available from: http://animals.about.com/od/birdsastudyguide/a/introtobirds.htm


3. Bird flight.2006-May-10[Internet]cited 2006-May-09.Available from: http://en.wikipedia.org/wiki/Bird_flight


Mr Elelwani Muanalo
NISL- Ecological Informatics Student
CSIR Pretoria
Tel: +27 12 841 2133
Fax: +27 12 842 7024.
Email: emuanalo@csir.co.za
My bloger URL: http://www.emuanalo.blogspot.com/

DISCUSS THE PROCESS OF FOSSILIZATION AND ITS SIGNIFICANCE IN THE INTERPRETATION OF EVOLUTIONARY EVENTS.

Fossilization is the process of change of matters into fossils. Fossils are the remains of animals, plants and organisms. They are many types of fossils which occur as result of different types of fossilization process. Fossil come in many different ways. They are different types of fossils and fossilization process fossils Each type of fossil is occurs as a results of different fossilization process and each tells scientist something about material conserve. Fossils consist of traces of remains of organism and mark left behind the organism while it was alive. E.g. footprint, trackways, bites marks and dwelling burrows. Fossilization is rare occurrence because most of the components of living things tend to decompose. Organism to be fossilized, the remains needs to be covered by sediments.

The term fossilization does not only refer to the remains of organism but also to the impressions in rock and traits form by organism when they are alive. Fossils are formed when living organism dies and the part of the body are kept safe. Burial prevents the destruction of organism by scavenger, bacteria or weathering and erosion. It is also important because oxygen is no longer available to bacteria that cause the decay. Fossilization favours the following organism: big organism with hard body parts, organisms that were widespread and organism that lived for a long time. It favours these because it is impossible to find the following: small fossils, soft bodied organism living in small areas that did not live for a long time, either because they become extinct or because they evolved quickly. Geological process such as erosion destroys many fossils.

Fossilization process start when living thing dies, flow down a river and lodges on a sandbar. The bone may get covered by mud or sand but the tissue and skin decomposed. In drier areas, animals may fall into a crack and be quickly covered by wind blown sand. Once burial has occurred the remaining process of fossilization can continue. During the period of some hundreds millions years sediments built up over the buried remains and the pressure drives water out and converts the sediments to rock.
During the life time of rock, water sort through it dissolves some minerals and deposit them at the other sites, and deposits different minerals at the original site of the fossil thus cause the fossil remains themselves become converted into different types of rock
The process of carbonization occurred in the process of fossilization, plant leaves, and some body parts of fish, and reptiles decompose going behind only the carbon. This carbon creates the idea in the rock giving the great details of fossil. Plants are commonly fossilised through carbonisation

Fossils are the main sources of information on the evolution. Without the information provide by fossil, we can not have no direct knowledge of timing of biological events such as the following: origin of life, the development of skeletons, the colonisation of the land, the appearance of mammals and the flowering plants, the development of flight and the major episode of extinction.

Fossils are the main source of information because it gives the history development and the evolutionary relationships of Morden flora and fauna. It also gives the knowledge and characteristics of extinct organism such as dinosaurs .

Reference

Wikipedia Contributor. Fossilisation [Internet]. Wikipedia, The free encyclopedia, 2006 May 4, 13:36 UCT [Cited 2006 May 8] Available From: http://en.Wikipedia.org/wiki/fossils

Linette Netshiheni
CSIR
Pretoria
0001
Cell: 0820446442
Tell: 012 841 2133
Fax: 012 842 3676
tnetshiheni@csir.co.za
Weblog: http://tnetshiheni-linette.blogspot.com/

THE STRUCTURE AND SIGNIFICANCE OF DNA TO OUR LIVES

Deoxyribonucleic acid (DNA) is a nucleic acid (“a complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information”) (2) that are in the form of a double helix. It is able to replicate itself due to its double helix structure. DNA contains “genetic instructions that specify the biological development of all cellular forms of life” (1). DNA is a long “polymer of nucleotides and it encodes the sequence of the amino acid residues in proteins using the genetic code mostly a triplets code of nucleotides” (1).

The DNA molecule is a chain of nucleotides. Each DNA molecule consists of sugar (deoxyribose-it has five Carbons and three Oxygen), a phosphate and one of five kinds of nucleobases (bases). DNA strands are composed of “nucleotide subunits called polymers” (1). DNA has five kinds of nucleotides which are commonly referred to by the identity of their bases (1). The bases are adenine (A), thymine (T), uracil (U), cytosine (C) and guanine (G). Uracil (U) is found in the DNA when cytosine (C) is chemically degraded”.

DNA is sometimes referred to as a “heredity molecule because it carries genetic propagation (when more DNA is produced from the original strand) of most inherited traits” (1). DNA can be transferred after been replicated from the parent to the offspring during reproduction. Each and every one of us has his or her own unique DNA and we have also inherited our genomes from our parents. A genome of an organism carries the whole hereditary information of an individual that is encoded in the DNA (4). Each individual inherits 23 chromosomes from each parent including the X-chromosome (mitochondrial DNA that we inherit from our mothers and Y-chromosome from our fathers (1).

The way in which the “DNA strands stay associated is determined by complementary pairing” (5). Each base forms hydrogen bonds A bonds with T and G with C. the hydrogen bonds between A to T is a double bond and between G to C is a triple bond. Since DNA is a double stranded helix it can also unfold into two single strands by the process called DNA replication. The two resulting double strands which are identical, each “synthesize a new strand by the process called semiconservative replication (the method in which DNA is replicated in all known cells)" (5).

The DNA molecule is always double stranded when it unfolds another strand is synthesized unless the DNA is mutated (change in genetic material) either chemically or during replication. The way the DNA unfolds it is like unzipping a zip of a jersey or any zip. DNA contains the genetic information that is inherited by the offspring and the way the base pairs are paired it determines how the offspring is going to be like. The way the base are determined tells whether the offspring is going to inherit what types of features from which parent. A DNA strands contain genes and areas where gene regulation takes place. Genes can be viewed as a “cookbook or blueprint” (3).

The significance of DNA to us as human beings is that we are able to trace back our ancestors for example scientists used DNA in order to try to find the missing link between “Ape to Man” and to the eight daughters of African Eve. Scientists used DNA in order to trace African Eve eight daughters so DNA is so important. DNA contains genes that parents pass on to their children so the generations can continue. Each and everyone of us has his or her own unique DNA so forensics can solve a crime easily using DNA and some people use it if they want to prove paternity to check if the childs DNA corresponds with the fathers. The problem with DNA is when it is mutated and the body cannot fix or "see" the mutated bases. The person who has mutated base pairs can either be physical deformed or mentally disturbed. For example if people who share the same genes (i.e. father and daughter) mate, the offspring will have no different genes, will have almost the same genes. Since the daughter would have inherited half of the genes from her father and want kind of a child are they going to have? Their child is going to have shared some of the genes with the daughter since they share the same father.

Reference:

1. Wikipedia contributors. DNA [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 01, 23:16. UTC [cited 2006 May 3]. Available from: http://en.wikipedia.org/wiki/DNA
2. Wikipedia contributors. Nucleic acid [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 01, 12:48. UTC [cited 2006 May 3]. Available from: http://en.wikipedia.org/wiki/Nucleic_acid
3. Wikipedia contributors. DNA replication [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 2, 04:25 UTC [cited 2006 May 3]. Available from: http://en.wikipedia.org/wiki/DNA_replication
4. Wikipedia contributors. Genomes [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 3, 04:39 UTC [cited 2006 May 3]. Available from: http://en.wikipedia.org/wiki/Genomes
5. Wikipedia contributors. Semiconservative replication [Internet]. Wikipedia, The Free Encyclopedia; 2006 Feb 3, 04:39 UTC [cited 2006 May 3]. Available from: http://en.wikipedia.org/wiki/Semiconservative_replication

Lethabo Mosomane
CSIR
Pretoria
0001
Tel: 27 12 841 2133
Fax: 27 12 842 3676
mail: lmosomane@csir.co.za
http://lmosomane.blogspot.com/

DIFFERENCES BETWEEN NEW WORLD MONKEYS AND OLD WORLD MONKEYS

Monkeys grow well in the subtropical and tropical regions of South and Central America, Asia and Africa where they are mostly dominated. "New world monkeys belong to order Platyrrhini they are limited to tropical environments and they are mostly herbivores. They feed on fruits, nuts and gums some also prey small insects. There are about 53 species of new world monkeys and they are divided into three families and sixteen genera these families include Callithricidae, Cebidae and Atelidae. The old world monkeys belong to the order Catarrhini which consists of two superfamilies"(1). The platyrrhini evolved from the ocean.

The new and old world monkeys look similar if you are observing them from a distance but if you take a close look you can see some unique and distinctive difference between them. These two monkeys can be easily differentiated looking at faces. "The new world monkeys have a flat face and their nostrils are far apart and open on the side. They have three molars which are very large but in most cases the last molar is smaller and in some monkeys they are not there. The ear of the new world monkey has a trampanic membrane connected to the external ear by a bony ring. They have different tails, but some species like howlers and spiders are composed of prehensile tails. The thumb orientation of their hands lies in the line with other digits while opposing the next digit in a scissor like grip. Some species like spider monkeys have lost their thumbs. Male species contribute a lot when it comes to infant care. The old world monkeys have a down facing nose with nostrils that are closer together and open down ward and sometimes forward. They have two premolars, premolar found in the mandible is sectorial meaning that it is specialised for sharpening the upper canine and their molars have sharply connected cusps. The tympanic membrane is connected to the external ear by the bony tube which is visible on the outside of the skull. Old world monkeys have tails all of them but they lack prehensive feature"(2). These tails are considered as the sitting pads as the monkeys sit on trees.

The thumbs are more like of modern people, they are rotated and more opposed. In some monkeys the thumbs are reduced or absent. The fingernails and toenails are present at all types of monkeys. The old world male monkeys do not have a close relationship with their infants.
They tolerate wide range of habitats, including rainforest, through savanna fringe or open savannah to semiarid regions. Many spend most of their day underground (2).

Reference

1. Wikipedia contributors. Monkeys [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 16; 15:40 UTC [Cited 2006 May 15]. Available from:
http://en.wikipedia.org/wiki/Monkeys

2. Wikipedia contributors. Comparisons [internet] Wikipedia, The free encyclopedia 2006 May 11; 16:05 UTC [cited 2006 May 11]. Available from:
http://www.cabrillo.edu/~crsmith/monkeycomparisons.html

Dianah Nangammbi
Cilla CSIR
P.O Box 395
Pretoria
0001
Tel: +27 12 841 2133
Cell: +27 73 121 3589
Email: dnangammbi@csir.co.za
http://wwwdianah.blogspot.com/

MORPHOLOGICAL DIFFERENCES THAT EXIST BETWEEN THE CARTILAGINOUS AND BONY FISH

Fish are vertebrate animals that live in water, they have stream lined muscular bodies and they are cold blooded animals. There are three different classes of fish and these include the jawless fish, cartilaginous fish and bony fish. Fish can be found world wide and exhibit amazing adaptations to live in every kind of water habitat. Some fish live exclusively in saltwater, some in fresh water and others in mixed water.
http://www.biologie.uni-hamburg.de/b-online/library/crone/3051/highli05.html

Bony fish are fish that have a skeleton made of bone. They have teeth that are fixed into the upper jaw and have a swim bladder (an air filled sac that helps them with resilience) that opens into the gullet. They are the members of animals called vertebrate. These are animals with backbone. Several examples of this interesting and diverse group are found at sea. They do not have to swim to breath. Most of the fish are bony fish; however sharks, skates and rays are not bony fish. http://curriculum.calstatela.edu/courses/builders/planets2000/-Gump/Limon/AQAnimal3/FISH.html#Bony

Cartilaginous fish have the skeleton which is made of cartilage. These “include sharks, rays and skates are cartilaginous. Fertilisation of eggs is internal. They have the scales that are placoid and are present all over the body surface. Once their scales are fully formed, they do not to grow but they replaced by new scale once they wear out.
http://www.biologyreference.com/Bl-Ce/Cartilaginous-Fish.html

These two fishes differs morphologically, the bony fish are the most diverse and numerous of all vertebrates. They differ from most of the cartilaginous fishes because they have a terminal mouth and a flap covering the gills most of them have a swim bladder which is ordinary use to adjust their buoyancy. Their skin has many mucus glands and is usually adorned with teeth. Most of their skeleton is bone that of sturgeon and few others is largely made of cartilage. In modern cartilaginous fish, lungs or swim bladder-like structures are absent efforts of swimming.
The bony fish have the skeleton with as small as amount of cartilage whereas the cartilaginous fish contains cartage only. Bony fish are able to swim backward and forward whereas the cartilaginous fish only able to swim forward. The cartilaginous fish consist of gill slits but no gills cover and the bony fish are covered with gill slits. The skin characterised of Slipper overlapping scales in bony fishes and in cartilaginous fish the skin is denticle rough sandpaper like placoid scales. http://curriculum.calstatela.edu/courses/builders/planets2000/-Gump/Limon/AQAnimal3/FISH.html#Bony

The bony have very good eyesight to avoid being prey. A swimming bladder keeps them floating just like fish on Earth. The unique thing about their swimming bladder is that they can efficiently extract oxygen from the water to fill their swimming bladders. The Cartilaginous fish do not have good eyesight; they make up for this with a good sense of smell. They are common in all the seas of Gump from the polar latitudes to the tropics.
http://www.biologyreference.com/Bl-Ce/Cartilaginous-Fish.html


Reference:

1. Hudson valley community college, 2000, life in the water, [Internet] Online Access: 2006 May 15 10:00 [cited 2006 May 16] Available from:
http://www.biologie.uni-hamburg.de/b-online/library/crone/3051/highli05.html

2. National geographic, 2000, fish of planet, [Internet] Online Access: 2006 May 15 13:00 [cited 2006 May 16] Available from: http://curriculum.calstatela.edu/courses/builders/planets2000/-Gump/Limon/AQAnimal3/FISH.html#Bony

3. Thomson gale, a part of the Thomson Corporation, 2006. Cartilaginous fish, [Internet] Online Access: 2006 May 16 14:30 [Cited 2006 16] Available from:
http://www.biologyreference.com/Bl-Ce/Cartilaginous-Fish.html

Mr Lufuno Mukwevho
CSIR Pretoria
P.O. Box 395
Pretoria,
0001
Tel: (012) 841 2133
Fax: 012 842 7024.
Cell: 0723175626
Email: lmukwevho@csir.co.za
My blog URL: http://mukwevholufuno.blogspot.com

MORPHOLOGICAL DIFFERENCES BETWEEN CARTILAGINOUS AND BONY FISH

Cartilaginous and bony fishes falls under the kingdom animalia. Vertebrates are organism that contains a back bone and all fishes contains a back bone which means that they are all vertebrates. The morphological structure of the two fishes is totally different. They are both very rough but catilaginous is more rougher.

Cartilaginous fishes are so called because of their lack of the real bone even though their bodies consist of a cartilage. "The cartilaginous fishes have strong jaws. The mouth of the cartilaginous fish is found underside of the head, while the eyes are found on top of the head. Cartilaginous fishes also possess the two nostrils which are used for smelling. They can not see food as it enters their mouth. Some Shark solve this problem by touching their food with their nose before they eat. Some use powerful electro sensory system. Sharks, Skates and rays have rough skin. Sharks have five to seven gills slits on each side of their head. But bony fishes have 1 gill on each side. Chimaeras or Gost shark have skins that are very smooth and have only one pair of external gill openings. Cartilage fish give live birth through their bodies, they prefer internal reproduction whereas bony fishes reproduce by laying eggs. Cartilages prefer water with high salt quantity only while bony fishes survive in all types of salt" (1)

"Bony fishes are very common and their example include gurnard and snapper. Bony fish are classified into Lobe finned and the Ray –finned. Lobe-finned bone fish includes fish such as lungfish and coelacanth’s, where as Ray-fins includes the goldfish, tuna, and trout. They contains a tail fin which is equal in both the proportion bottom and top. They have a bony skeleton and single pairs of external gill openings. The mouth is generally at the front of the body. It has relatively short tube. Bony fish reproduce by external fertilisation of eggs and releases them into water. The male releases sperm called Milt into water. Milt combines with the eggs and fertilisation takes place" (1)

Their liver is filled with oils which keep them from sinking. They have internal fertilisation. The bones of fish are made mostly by calcium but Shark does not have any bones. Shark skeleton is made of cartilage, and have no bladder, but bony fish have a gas filled swim bladder which enables them to float in the water. Bony fish have movable parts were as shark does not have. Shark can turn around in a smaller space than bony fish.The brain of the ghost sharks is closely related to that of the birds and mammals. As compared to that of the bony fish, the brain of the cartilaginous is ten times to that of the bony fish. While the brain size of the bony fish is thought to closely relate to that of the human beings, the reason of having such a big brain because they use a lot of energy.

Reference

1. Studios, A.R. 1997 Biology for kids vertebrates fish [Internet]. [Cited 2006 May 16] Available from:http://www.biology4kids.com/files/vert_fish.html[2006

2. The wikipedia contributor, Cartilaginous [Internet] Wikipedia, The free encyclopaedia; 2006 May 16; 16:13 UTC [Cited 2006 May 16] Available from:
http://en.wikipedia.org/wiki/Cartilaginous


Dianah Nangammbi
Cilla CSIR
P.O Box 395
Pretoria
0001
Tel: +27 12 841 2133
Cell: +27 73 121 3589
Email: dnangammbi@csir.co.za
http://wwwdianah.blogspot.com/

DIFFERENCES BETWEEN NEW WORLD MONKEYS AND OLD WORLD MONKEYS

Monkeys are living species of the suborder anthropoidea. They are divided into three groupings of simian primates, which are the old world monkeys and new world monkeys. These types of species are the most successful primates populating the earth than others. They are more than 246 know species which are living today. But some are not exact monkeys; they only have similarities that monkeys have. “Apes such as chimpanzee and gibbons they are sometimes called monkeys”.1 suborder anthropoidea has also divided into other super families such as Cercopithecidea which is regarded as the old world monkeys, they mostly found in the continent of Africa and Asia. While Cebidae, Aotidae, Pitheciidae, Atelidae is regarded as new world monkeys. [1]

Monkeys have differences that can separate them to each other, features that old monkeys have is different to the ones that new world monkeys. “Platyrrihini as known for the new world monkeys they have flat nose as compared to catarrhine (old monkeys)”2 3.their nostrils are separated by a wide septum, while of the catarrhine are separated by a small septum. “The molars of new world monkeys are large compared to the teeth of old monkeys which are two sharply connected cusps”.2 These kinds of features that are presented on this class of monkeys differentiate them. [2]

New world monkeys also have some feature that are total different the ones that old monkeys have, “they have long tails which is known as prehensile tails”.2 It is used as the third hand to grab things and also give balance when they climb branches of trees. While the old monkeys do not have long tails, because they are not arboreal which will require their tail as the third hand? Another difference between these two monkeys is their body; the old world monkeys are having large body size which have colours especially on the face where it has bright colourful colours. On the other side new world monkeys are having dark colours and small body with lots of fur that made them look big. [3]

Furthermore characteristics that are presented by this two super class also differentiate them to each other. “Male of new world monkey involves itself on parenting of the infant, it was suggested that most of the time the male will carry the infant on its back and return it to its mother for nursing”.2 While the old monkeys male never get involve with the caring of the infant, is only done by female monkeys. [2]

These differences are also adopted in the way they chose habitant, new world monkeys mainly live in trees. While catarrhine live in various habitats, they spend most or some of their day on the ground. These old monkeys have hairless callous pads, on their rumps which may be adaptations for long sitting or sleeping on rough branches and stone and the new world monkeys do not have that marks ,which shows that they mostly found on trees.
They only have one common thing, their diet are the same. All monkeys are herbivores they live on vegetables and fruits. Monkeys are intelligent, they behave like humans. This made them to be in the same family tree as human is, because it has been suggested by paleothropologist that we share the same ancestor as this species.

In conclusion, it is easier to differentiate the old world from the new world monkeys simply by their appearance, when you are distanced from them you can check their colours, body weight and when you are not far you can also check their facial appearance as they are different. Also their characteristics are different new world monkeys prefer to live on trees while the old monkeys occupy different habitant and they prefer to live on ground than on trees. All these monkeys irrespective of their differences they share one common character, both of them are intelligent and they behave like humans.

Reference:

1. Wikipedia contributors, Monkeys. [Internet]. Wikipedia, The Free Encyclopedia; [cited 2006 May 12]. Available from: http://en.wikipedia.org/wiki/Monkeys

2. Anthropology 1, new world (America) and old world (Africa and Asia) monkey: A comparison, [internet] [cited 2006 May 11] Available form:http://www.cabrillo.edu/~crsmith/monkeycomparisons.html

3. Wikipedia contributors, Monkeys. [Internet]. Wikipedia, The Free Encyclopedia [cited 2006 May 12] Available from: http://en.wikipedia.org/wiki/New_World_monkey.

Mr Elelwani Muanalo
NISL- Ecological Informatics Student
CSIR Pretoria
Tel: +27 12 841 2133
Fax: +27 12 842 7024.
Email: emuanalo@csir.co.za
My bloger URL: http://www.emuanalo.blogspot.com

DISCUSSION OF ECHOLOCATION IN BATS AND WHALES

The echolocation is the ability that bats and whales posses and enables them to locate and discriminate objects by listening for echoes. Bats and whales use echolocation for different purposes for instance hunting, navigating and to judge the distance of the object.

Bats have ability to hear the sound when it bounces off from the object. When an object hits an echo sound come back to the bats (5). They can able to estimate the distance, movement as well as well as size of the objects in their way. They can even tell the shape and texture of tiny insects from its echo. Some bats send echolocation sound through their nose but the majority of bats use their mouth. They hold their mouth open as they fly.

Different species of bats uses different pattern of echolocation frequencies to find food and navigate. There are some species that produce constant frequency (CF) cry and those that use modulated (FM) call descend in pitched. “High frequency echolocation calls produced by bats range from 20-200 kilohertz" (1). It is difficult for human to hear the high pitched sound of the bats.

In the basic principles of echolocation, bats produce sound the same way as humans do, by moving air past their vibrating vocal chord. Bats use this echolocation process to gather information in order to see the world around them. Scientists believe that the strange noise that found in some bats, serves to focus the noise for more accurate pin pointing of insects such as grasshopper, moths, beetle and other prey.

The brains of bats process the returning information the same way. The bats are able to detect if the insects is on the left or right by using the sound. If the sound reaches the right ear before it reaches the left ear it means that the insects are on the right. The bats have ears which have complex collection of folds of the outer ear that help it to determine the vertical position of an insect. Echoes coming from below will hit the folds of the outer ear at different point than sounds coming from above, and so will sound different when they reach the inner ear of the bats.

Whales used echolocation for navigation and hunting. “Toothed whales developed the capability of emitting sounds that travel from their melons or foreheads and reflect off objects” (2). Toothed whales echo locate by producing clicking sounds and then receiving and interpreting echo. Toothed whales use echolocation to sense objects. Whales sent out high pitched whales, the sound bounces off, the objects and some returns to the whales. The whale interprets the returning echo to determine the objects shape, direction and distance. Toothed whales produce sound to overlapping functions. That is communicating and echo locating.

Tones of lower frequencies that are produced by whales include groans and moans. These sounds make a lot of noise and travel a long distance. The echoes produced by these sound can be used by whales to navigate. Thereafter, echoes returned as allow the frequency sound to bounce off of features in the oceans basis such as islands, sea mounts and continental shelves, and this could easily give the whales information about its environment. The sound also gave the whales little information about the other in the closer surrounding area.

Echolocation plays an important role into the life of bats and whales. Both whales and bats are able to hunt food, navigate and to judge the distance in which the insects is located. They have capacity to emit sound that travel like waves and reflect object.

References

1. Bennu A.N. The night is alive with the sound of Echoes [Internet].Catching Dinner on the Fly...; 2006 May 24, 11:03 UTC [Cited 2006 May 24]. Available from: http://research.amnh.org/users/nyneve/bats.html

2. Drum L. Cetacea. Echolocation [Internet]. Mammals; 2006 May 24, 11:03 UTC [Cited 2006 May 24]. Available from: http://nmml.afsc.noaa.gov/education/cetaceans/cetaceaechol.htm3
3. Kruse M. Echolocation in the bat [Internet]. Model System in Neurothology; 2006 May 24, 11:03 UTC [Cited 2006 May 24]. Available from: http://www.npa.uiuc.edu/courses/physl490b/models/bat_echolocation/bat_echolocation.html

4. Harris T. Seeing with sound [Internet]. How bats work; 2006 May 24, 11:03 UTC [Cited 2006 May 24]. Available from: http://science.howstuffworks.com/bat2.htm

5. Phillips J.D.Whales [Internet]. Marine Research Program; 2006 May 24, 11:03 UTC [Cited 2006 May 24].Available from: http://whale.wheelock.edu/archives/ask98/0306.html

6. Roth J. Echolocation [Internet]. National Parks; 2006 May 24, 11:03 UTC [Cited 2006 May 24].Available from: http://www.eparks.org/wildlife_protection/wildlife_facts/bats/echolocation.asp

7. Wikipedia Contributors. Bats [Internet] Wikipedia, The Free
Encyclopedia; 2006 May 09, 13:07 UTC [cited 2006 May 09]. Available from: http://en.wikipedia.org/wiki/Bats

8. Wikipedia contributors. Whales [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 09; 12:09 UTC Available from: http://en.wikipedia.org/wiki/Whales

Masiya Kedibone
CSIR Pretoria
0001
Cell No: 073 2519071
Tel No: 012 8412123
Fax: 012 842 3676
E-mail:kmasiya@csir.co.za

NEW FACES @ NISL-EI: GWEN RAITT


Gwen has been working these past few weeks on the Biodiversity Chapters (One, Three and Four). Gwen comes from a Biological Family since her father Lincoln Raitt is a Professor in our Department. Gwen has a Masters in Botany from the University of Stellenbosch and she did her research on Renosterveld (a grassland) is the southern Cape. She also has a degree in Nature Conservation, also from Stellenbosch.

NEW FACES @ NISL-EI: NICKLAUS


This is Nicklaus Kruger, but we just call him Nick. He has completed his Honours at UCT in Zoology and will help develop content (Conservation Biology) but at the moment he and Gwen Raitt are helping out on the Biodiversity Questions. Already some of you postings have some comments up.

In his own words he described last year as



it turns out that a detailed knowledge of mole skull-shapes and a passion for chronicling the wars of termite colonies isn't really all that useful in that scary and dangerous place they call The Real World.




Hopefully you are not finding the employed world such a scary place.