Science Folio: Support And Movement

SMK Seri Hartamas Support and Movement 2008 Name: Badrizza bte Suhaili Class: 2 Cekal Subject: Science Name of Teacher: En. Nasri

Index

N o 1 2 3 4

Title Acknowledgement Objectives Introduction Discussion:-

Page 1 2 3 4~18

~Frog ~Grasshopper ~Leech ~Centipede ~Question 6 = a, b & c

5 6 7 8

Conclusion Action Plan Reference Student Manual

19~20 21~22 23~24 25~26

Acknowledgement I would like to take this opportunity to show my gratitude to the people who helped me finish this portfolio. Firstly, I would like to thank my Form 2 Science teacher, En. Nasri for his guidance, care throughout this portfolio and giving me encouragement.. Secondly, I would like to thank my friends and classmates for helping me and share information with me. Last but not least, my parents for giving me support throughout this whole portfolio.

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Objectives 1. Classifying various animals based on their support systems. 2. Explain the support systems in vertebrates and invertebrates. 3. Compare and contrast the support system between centipede and grasshopper. 4. Classifying frog, grasshopper, leech and centipede based on common characteristics.

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Introduction The support system is very important to all animals. Without a support system, the body would just collapse. For example, the elephant will not have any particular shape. It will not be able to raise it’s body above the ground. Therefore will have great difficulty walking on land. Soft bodied animals such as sea anemones and earthworms are supported by liquid which consists mainly of water in their cells and in spaces between their body organs. These animals are said to have hydrostatic skeleton. Insects such as grasshoppers and cockroaches, and crustaceans such as prawns and crabs are supported by a skeleton of hard material which forms the outside of their bodies. This outer skeleton is

called the exoskeleton. In vertebrates, the skeleton is inside the body and muscles are attached to it. This internal skeleton is called endoskeleton. All vertebrates have endoskeleton which consists of bones an cartilage. However, aquatic vertebrates have smaller endoskeletons when compared to land vertebrates of the same body mass. This is due from support of the buoyancy. Buoyancy is the force from water which allows an object to float. In general, the hydrostatic support system is ideal for aquatic invertebrates. However organisms living on land are subjected to relatively greater gravitational forces then in water. Therefore majority of land invertebrates have rigid support systems to maintain their body forms. This support system is called exoskeleton. The outer covering of the exoskeleton of insects is called the cuticle and it is made of chitin, a substance similar to cellulose. The exoskeleton or shell of snails consists mainly on calcium carbonate. 3

Discussion

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Frog

Frogs are amphibians in the order Anura (meaning "tailless", from Greek an-, without + oura, tail), formerly referred to as Salientia (Latin saltare, to jump). The name frog derives from Old English frogga, (compare Old Norse frauki,

German Frosch, and older Dutch spelling kikvorsch), cognate with Sanskrit plava (frog), probably deriving from Proto-IndoEuropean praw = "to jump". Amphibians are cold-blooded (or poikilothermic) vertebrate animals. They are over 5000 different species of frogs. Frogs have the characteristics of: • • • • •

Two bulging eyes Strong, long, webbed hind feet that are adapted for leaping and swimming Smooth or slimy skin (generally, frogs tend to like moister environments) Frogs tend to lay eggs in cluster. Absence of a tail.

Most frogs are found in tropical rainforests, wet marshes, lakes, rivers, ponds and puddles. The support system for frogs is endoskeleton that allows it to support its weight, give a shape, protects the internal organs, provides a surface for muscle to attach to and works together with muscles to enable body movement. When Frogs mate, the male frog tends to clasp the female underneath in an embrace called amplexus. He literally climbs on her back, reaches his arms around her "waist", either just in front of the hind legs, just behind the front legs, or even around the head. Amplexus can last several days. Usually, it occurs in the water, though some species, mate on land or even in trees. While in some cases, complicated courting behaviour occurs before mating, many species of frogs are known for attempting to mate with anything that moves which isn't small enough to eat. Thus they reproduce externally. 5 Once adult frogs reach maturity, they will assemble at a water source such as a pond or stream to breed. Many frogs return to the bodies of water where they were born, often

resulting in annual migrations involving thousands of frogs. In continental Europe, a large proportion of migrating frogs used to die on roads, before special fences and tunnels were built for them. Most temperate species of frogs reproduce between late autumn and early spring. They have a different variety of eyes like round pupils, vertical pupils, horizontal-shaped pupils, triangular pupils, star-shaped pupils and heart-shaped pupils. Frogs must be able to move quickly through their environment to catch prey and escape predators, and numerous adaptations help them do so. Frogs are generally recognized as exceptional jumpers, and the best jumper of all vertebrates. The acceleration of the jump may be up to twice gravity. There are tremendous differences between species in jumping capability, but within a species, jump distance increases with increasing size, but relative jumping distance (body-lengths jumped) decreases. Many frogs are able to absorb water and oxygen directly through the skin, especially around the pelvic area. However, the permeability of a frog's skin can also result in water loss. Camouflage is a common defensive mechanism in frogs. Certain frogs change colour between night and day, as light and moisture stimulate the pigment cells and cause them to expand or contract. Many frogs contain mild toxins that make them unpalatable to potential predators. The chemical makeup of toxins in frogs varies from irritants to hallucinogens, convulsants, nerve poisons, and vasoconstrictors. Many predators of frogs have adapted to tolerate high levels of these poisons. Others, including humans, may be severely affected. The skin of a frog is permeable to oxygen and carbon dioxide, as well as to water. There are a number of blood vessels near the surface of the skin. When a frog is underwater, oxygen is transmitted through the skin directly

into the bloodstream. On land, frogs use their lungs to breathe. Their lungs are similar to those of humans, but the chest muscles are not involved in respiration, and there are no ribs or diaphragm to support breathing. 6

The picture on the top left is the skeletal system of the frog while the one on the top right is a type of poisonous frog.

The frog on the left is a type of frog that illustrates the large toe pads and webbed feet.

The dark coloured parts of this map, shows the distribution of frogs across the whole world. 7

Grasshopper

Grasshoppers are insects of the suborder Caelifera in the order Orthoptera. The support system for grasshoppers is exoskeleton that allows it to maintain it’s shape of the body, protects the soft tissue of the body, protects animal from predator, limits water loss from body, provides surface for muscles to attach to and works together with the muscles to enable body movement. The family acrididae includes more then 8,000 species of grasshopper and locusts distributed world wide. Grasshoppers are found in almost all types of habitat including the tropics, temperate grasslands, rainforests, deserts and mountains. If adverse condition prevail, some species migrate in huge numbers to maximise survival. Grasshopper feed on grass, leafy plants and bushes. Some species eat only particular food plants but most species broadened their food base following depletion of

their preferred food. Maintaining a appropriate moisture content in the body is achieved primarily through food selection. All species of grasshoppers consume both wet and dry food. However hydrated insect will choose leaves with low water content, with a dehydrated one selects leaves higher in moisture. Captive grasshoppers will drink water directly when food moisture drops below about 50%. Respiration is performed using tracheae, air-filled tubes, which open at the surfaces of the thorax and abdomen through pairs of spiracles. The spiracle valves only open to allow oxygen and carbon dioxide exchange. The tracheoles, found at the end of the tracheal tubes, are insinuated between cells and carry oxygen throughout the body. During reproduction, the male grasshopper introduces sperm into the ovipositor through its aedeagus (reproductive organ), and inserts its spermatophore, a package containing the sperm, into the female's ovipositor. The sperm enters the eggs through fine canals called micropyles. 8 The female then lays the fertilized egg pod, using her ovipositor and abdomen to insert the eggs about one to two inches underground, although they can also be laid in plant roots or even manure. The egg pod contains several dozens of tightly-packed eggs that look like thin rice grains. The eggs stay there through the winter, and hatch when the weather has warmed sufficiently. Grasshoppers have antennae that are almost always shorter than the body (sometimes filamentous), and short ovipositors. Those species that make easily heard noises usually do so by rubbing the hind femurs against the forewings or abdomen (stridulation), or by snapping the wings in flight. Tympana, if present, are on the sides of the first abdominal segment.

The hind femora are typically long and strong, fitted for leaping. Generally they are winged, but hind wings are membranous while front wings (tegmina) are coriaceous and not fit for flight. Females are normally larger than males, with short ovipositors. Males have a single unpaired plate at the end of the abdomen. Females have two pairs of valves ( triangles) at the end of the abdomen used to dig in sand when egg laying.

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This shows the anatomy of a grasshopper.

This picture shows a grasshopper in camouflage.

A picture of a grasshopper from underneath. 10

Leech Leeches are annelids comprising the subclass Hirudinea. There are freshwater, terrestrial, and marine leeches. Like the Oligochaeta, they share the presence of a clitellum. Like earthworms, leeches are hermaphrodites. The leech support system is hydrostatic skeleton. Some, but not all leeches feed on blood. Haemophagic leeches attach to their hosts and remain there until they become full, at which point they fall off to digest. Leeches are found in a wide variety of habitats. Those living in the ocean and astuaries, or wide areas where rivers join the sea are found on rocks, plants, or attached to fish or other sea animals. Species living on land are found in moist habitats such as rainforests or wet coastal forests. They are usually found clinging to plants or under rocks. Freshwater species live in swamps, ponds, streams, and rivers where they live on wood, rocks, vegetation or on other animals. Most leeches are plattened from top to bottom and measure 0.196 to 0.787 inches in length. Leeches have eyespot on their head that are able to detect movement from contrasting patterns on light and shadow. The mouth is located underneath the head. Like earthworms, leeches have a ditallum, a specialised collarlike band behind the head. The tail sucker is used for swimming, getting around or remaining attached to a host. Blood feeding species have special pouches that allows them to increase their intake of fluid. They can expand up to six times their normal weight. Many leeches swim through the water in a snakelike motion. Species living on land move

along the ground like an inchworm, stretching, shortening their bodies by using the suckers on both ends.

11 A leech's body is composed of 34 segments. They all have an anterior (oral) sucker formed from the first six segments of their body, which is used to connect to a host for feeding, and also release an anesthetic to prevent the host from feeling the leech. They use a combination of mucus and suction (caused by concentric muscles in those six segments) to stay attached and secrete an anti-clotting enzyme, hirudin, into the host's blood stream. Leeches are hermaphrodites, meaning each one of them has both female and male reproductive organs. Leeches reproduce by reciprocal fertilization, and sperm transfer occurs during copulation. The leech exercising the role of the male will grow a sperm sack near the end of its tail, and the leech playing the female will bite it off, thus reproducing. Similarly to the earthworms, leeches also use a clitellum to hold their eggs and secrete the cocoon. The ditellum is filled with special tissues that secrete a protective covering orcase for the eggs. During reproduction leeches utilize hyper-dermic injection of their sperm. They use a spermatophore, which is a structure containing the sperm. Once next to another leech, the two will line up with their anterior side opposite the others posterior. The leech then shoots the spermatophore into the clitellum region of the opposing leech where its sperm will make its way to the female reproductive parts.Some species of leech will nurture their young, while providing food, transport, and protection; which is unusual behavior in an invertebrate.

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This picture shows a leech on a wet rock.

This picture shows a leech searching for prey.

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Centipede Centipedes (from Latin prefix centi-, "hundred", and Latin pes,pedis, "foot") are arthropods belonging to the class Chilopoda and the Subphylum Myriapoda. They are elongated metameric animals with one pair of legs per body segment. A key trait uniting this group is a pair of venom claws or forcipules formed from a modified first appendage. This also means that centipedes are an exclusively predatory taxon, which is uncommon. The support system of a centipede is the exoskeleton. Size can range from a few millimetres to about 30 cm. Worldwide there are estimated to be 8,000 species. Centipedes are found in an array of terrestrial habitats from tropical rainforests to deserts. Within these habitats

centipedes require a moist micro-habitat due to their rapid rates of water loss. Accordingly, they are found in soil and leaf litter, under stones and deadwood, and inside logs. In addition, centipedes are one of the largest terrestrial invertebrate predators and often they contribute a significant proportion to invertebrate predatory biomass in terrestrial ecosystems. Centipedes have a flattened, segmented body, long antennae, and many legs (each leg is slightly longer than the one in front of it). Centipedes have from 15 to about 177 segments (but most have about 15). Each body segment has a pair of legs that stick out from the sides. A member of the genus Geophilus has 177 pairs of legs. When a leg is cut off it will regenerate. The body is divided into two parts, the head and a segmented trunk. They breathe through spiracles, holes positioned along the body. Centipede reproduction does not involve copulation. Males deposit a spermatophore for the female to take up. In one clade, this spermatophore is deposited in a web, and the male undertakes a courtship dance to encourage the female to engulf his sperm. In other cases, the males just leave them for the females to find. In temperate areas egg laying occurs in spring and summer but in subtropical and tropical areas there appears to be little seasonality to centipede breeding. 14 Number of eggs laid ranges from about 10 to 50. Time of development of the embryo to hatching is highly variable and may take from one to a few months. Time of development to reproductive period is highly variable within and among species. The female in some species stays with the young after they have hatched, guarding them until they are ready to leave. If disturbed the females tend to either abandon the eggs or young or to eat them; abandoned eggs

tend to fall prey to fungi rapidly. Some species are matriphagic, meaning that the offspring eat their mother. Centipedes are found in moist microhabitats. Water relations are an important aspect of their ecology, since they lose water rapidly in dry conditions. Water loss is a result of centipedes lacking a waxy covering of their exoskeleton and excreting waste nitrogen as ammonia, which requires extra water. Centipedes deal with water loss through a variety of adaptations. Spiracle shape, size and ability to constrict also have an influence on rate of water loss. In addition, it has been suggested that number and size of coxal pores may be variables affecting centipede water balance. Centipedes are carnivores (meat-eaters) that use venom to kill their prey. The venom comes from glands that open near the first pair of modified legs (which act as poisonous fangs). Their bite can be painful to a human but not lethal. Centipedes eat insects, earthworms, spiders, slugs, and other small animals.

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This picture shows a centipede crawling on the ground.

A centipede protecting its eggmass.

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Questions 6.a) Compare the support system of the centipede and the grasshopper and state one similarity between them. The centipede and grasshopper are categorised in exoskeleton and both of them have legs.

6.b) Compare the support system of the leech and the frog and state one difference between them. Leeches have hydrostatic skeleton and frogs have endoskeleton. Frogs are supported by bones while leech is supported by the buoyancy of water.

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Frog, Grasshopper, Leech and Centipede 6.c)

Endoskeleton

Exoskeleton

~Elephants ~Humans ~Frogs ~Horse ~Dog

~Prawn ~Crab ~Snail ~Grasshoppe r ~Centipede

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Hydrostatic Skeleton

~Earthworm ~Starfish ~Jellyfish ~Caterpillar ~Leech

Conclusion

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Frog, Grasshopper, Leech And Centipede

Vertebrates

Invertebrates

~Frog ~Human ~Horse

~Centipede ~Leech ~Grasshopper

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Action Plan

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N o 1

Activity

Date Action

Listen to the teacher’s explanation. Collect information

26 Sept 08

3

Preparing the scrap book

28 Sept 08

4

Binding the scrap book

29 Sept 08

2

27 Sept 08

~took brief notes. ~went to internet and library to find informati on ~wrote on the scrapboo k ~went to the store and bind it

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Reference

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Reference I have referred to the following things:1. Internet ~ http://en .wikipedia.org/ 2. Book ~ Science Form 2 Textbook 3. Human Source ~ En. Nasri

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