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Organismoa: Izaki bizidun bakoitza. Espeziea: Ezaugarri bereko organismoek osatzen duten taldea.

Nowadays we travel long distances on land by car, bus and train. But for millions of years, prehistoric people walked. We think that wheels were invented 5,000 years ago by the Mesopotamians . The wheels were made from solid wood. Animals pulled carts on wheels. A thousand years later, spokes were added which made the wheels much lighter. The first vehicle to move by itself was the steam tractor, invented in 1769 by the Frenchman Nicolas Cugnot . The steam tractor worked by pumping pistons up and down to move the wheels. But the tractor was very heavy and unstable. The first steam train was built in England in 1804 by Richard Trevithick and travelled at 8 kph. In 1829, George Stephenson and his son Robert won a competition to invent the fastest steam train. The Stephensons’ ‘Rocket’ could travel at 48 kph. Transport on the road and rail was further advanced by the invention of the internal combustion engine in 1859. The combustion engine worked by burning fuel inside

Thomas Edison was born on February 11th, 1847 in the USA. At school, Thomas was punished and beaten for asking too many questions. And when the teacher said that Thomas was a bad learner, his angry mother educated him at home. Thomas started work when he was twelve years old, selling newspapers on the railway. In his free time, he experimented with electrical and mechanical apparatus. One day, he saved the life of a child, and as a reward he was taught telegraphy. Telegraph operators sent messages down telegraph lines by using a code, which represented the alphabet. While he was working as a telegraph operator, he invented the automatic telegraph system , an instrument that could send messages over a telegraph line automatically, without an operator. In 1877, he invented the phonograph : a machine that could record and play back the human voice. The first words ever to be recorded and then played back were “Mary had a little lamb...” It took ten more years to ma

Leonardo da Vinci was born on April 15th, 1452 in Tuscany, Italy. His other and father were not married and he spent the first years of his life with his peasant mother in the countryside where he learned to observe and love nature. Leonardo then went to live with his father’s wealthy family in Florence where he was given a good education and he started drawing. At the age of fourteen he joined Verocchio’s painting studio as an apprentice. Leonardo is most famous for his paintings. He developed new techniques to paint with perspective and shadings. His most famous paintings include ‘The Last Supper’ and the ‘Mona Lisa’. However, Leonardo also kept notebooks (often in mirror writing) and drawings on architecture, elements of mechanics and human anatomy. Leonardo liked to observe everything around him and describe and depict it in great detail. He observed flight and designed a helicopter and a hang glider. For wealthy leaders he designed bridges and military

Stephanie Kwolek was born on July 31st 1923 in New Kensington (USA). Her father died when she was only ten years old, but he inspired her to be interested in science. She wanted to study medicine while growing up in New Kensington, but she studied Chemistry at university. After finishing her degree, she took a temporary research job with DuPont, an American chemical company, where her work became to be so interesting that she decided to stay. She was one of the first women research chemists, and she became famous in 1964 when she invented ‘Kevlar’. At the time there was a shortage of petrol for cars, and so Dupont wanted to develop lighter tyres for cars. Kwolek invented a liquid crystalline polymer solution which was so strong that it led to the invention of Kevlar, a synthetic material that is five times as strong as steel! Kevlar is resistant to corrosion and fire, and it is the main ingredient in the production of bullet-proof vests for the police and the army.

Marion Donovan was born on October 15th, 1917 in Fort Wayne (USA). She came from an inventive family, because her father and uncle invented an industrial machine for cutting automobile gears and guns. As a child, she spent a lot of time watching her father and uncle at work. Years later, after World War II, she was a housewife and a mother of two babies in Connecticut. She got fed up spending the entire day changing the babies’ wet nappies and the wet bed, time and time again. So she decided to make a nappy that could absorb water to keep her babies dry. Donovan sat down at her sewing machine with a shower curtain and created a waterproof nappy cover. Donovan improved her invention, adding snap fasteners instead of safety pins to close the nappy. Donovan called her nappy cover the “Boater” and explained that “at the time I thought that it looked like a boat.” No manufacturers were interested in her invention, so Donovan sold the nappies at the famous shop ‘Saks

Galileo Galilei was born in Pisa in 1564. He studied at Pisa University and he was a brilliant student. In 1592 he was appointed professor at the University of Padua where he stayed until 1610. In 1592, Galileo invented a crude air thermometer . In 1608 he started work on a telescope . Using basic sketches from the Netherlands, Galileo built a much more powerful telescope and used it for astronomical observations. He discovered the satellites of Jupiter, and saw the surface of the moon. He also confirmed that Copernicus’ theory that the Sun, not the Earth, was the centre of the Solar System. Until the 16 th century, humans believed that the Earth was the centre of the Universe and that the Sun revolved around it. The Church said that God had created Man in the image of himself, so, naturally, he had put the Earth in the centre of the universe. Galileo’s defence of Copernicus’ Sun-centred theory brought him problems with the Church. In 1633, Galileo was sentenc

Charles Babbage was born in London in 1791. He was very good at Mathematics and when he went to Cambridge University in 1810, he already knew more about calculus and algebra than the professors. He later became a professor of Mathematics at Cambridge and founded the Analytical and Statistical Societies. By the middle of the 18th century, complicated calculations were needed in navigation, banking, industry etc. These calculations were done by hundreds of human adding machines. There were lots of mistakes, of course. In 1812, Babbage, as a student, decided that a machine could calculate all the mathematical tables automatically. So in 1824 he started to build “the largest calculating engine that could ever be needed”. His first plans were for the table-making Difference Engine . It would calculate tables mechanically and even print them out so there would be no room for human error. By 1832, the Difference Engine had still not been completed but Babbage had desi

William Kellogg was born on April 7th, 1860. He left school in the sixth grade and at the age of fourteen began working as a salesman in his father’s business. Later he worked with his brother, Dr John Harvey Kellogg, at the Battle Creek Sanatorium. He helped his brother to try and improve the vegetarian diet of the patients. The patients were not allowed to have caffeine, meat or alcohol or to smoke tobacco. One day in 1894, they left some corn boiling in the kitchen and forgot about it. When they returned, they found that the corn had turned into thin flakes. Accidentally, they had invented ‘corn flakes’. They started serving it to their patients and it immediately became very popular. In 1906, William Kellogg founded the Battle Creek Toasted Corn Flake Company to produce ‘Kellogg’s Corn Flakes’. He expanded his business to Australia in 1924 and to England in 1938. In 1925, he established the Fellowship Corporation to help poor people. The Corporation helpe

Levi Strauss was born in Buttenheim, Bavaria (Germany) on February 26, 1829 to Hirsch Strauss and his second wife Rebecca Haas Strauss. He did not receive much schooling and when he was 16 years old, he decided to join his five brothers and sisters in the United States. In 1845 Levi sailed to New York. He spent some years learning the language and then he joined his family’s clothing business. In 1850 he moved to San Francisco when gold was discovered in California. The gold miners wanted clothes that were strong and did not tear easily. So he started selling clothes and opened a store. It was called “Levi Strauss & Co.” When miners wanted a pair of trousers, he tried to make them using a material called canvas, which he dyed indigo blue to cover up dirt and stains and added metal rivets to hold the pockets and the fly together. The famous blue Levi jeans had been invented. In 1886 Levi sewed a leather label onto the jeans. The label showed a picture of a

The French child inventor Louis Braille was born near Paris in France in 1809. Louis was a bright and inquisitive child. At the age of 3, when he was playing in his father’s shoe shop, Louis injured his eye with a sharp tool. Infection set in and soon spread to the other eye, leaving him completely blind. Louis’ parents, together with the local priest and the schoolteacher, had realised Louis’ great learning abilities and wanted to give him all the opportunities to develop them. So, he used to sit in the classroom to learn what he could by listening. Despite his handicap, he was soon top of the class. At the age of 10, Louis was sent to a special school for the blind in Paris where most instruction was oral, although there were some books (only 14 in the school) in a raised-print system developed by the school’s founder. Louis did very well at his studies and developed a talent for music, especially the piano and the organ. Because of his handicap he decided to

Nowadays we travel long distances on land by car, bus and train. But for millions of years, prehistoric people walked. Wheels were invented 5,000 years ago in Mesopotamia. They were made from solid wood. Animals pulled carts on wheels. thousand years later, spokes were added which made the wheels much lighter. The first vehicle to move by itself was the steam tractor , invented 1769 by the Frenchman Nicolas Cugnot. The steam tractor worked by pumping pistons up and down to move the wheels. But the tractor was very heavy and unstable. The first steam train was built in England in 1804 by Richard Trevithick and travelled at 8 kph (kilometres per hour). In 1829, George Stevenson and his son Robert won a competition to invent the fastest steam train. The Stephensons’ ‘Rocket’ could travel at 48 kph. Transport on the road and rail was further advanced by the invention of the internal combustion engine in 1859. The combustion engine worked by burning fuel inside cylind

Ikerketarako elkarrizketak planifikatzea oso garrantzitsua da helburua betetzeko; hau da, ezinbestekoa da elkarrizketa ondo antolatzea, egingo diren galderak zehaztea, izango den jarrera aurrez planifikatzea eta datu-bilketa nola egingo den definitzea. Beraz, elkarrizketa planifikatzeko eta garatzeko, arretaz jokatu eta honako hauek kontuan hartu: 01. Zehaztu elkarrizketaren helburua. 02. Prestatu galdera-zerrenda. Egokitu lortu nahi den helburuarekin eta ordenatu. 03. Aztertu nork izan dezakeen informazioa zuek jarritako helburua lortzeko. 04. Aukeratu elkarrizketatuko dituzun pertsona edota pertsonak. 05. Jarri harremanetan elkarrizketatuko duzun horrekin. Horretarako, adierazi garbi elkarrizketatuari nor zaren eta nondik zatozen. Ondoren, jakinarazi elkarrizketaren helburua. 06. Tratatu begirunez elkarrizketatua, eta gogoratu elkarrizketa ikasteko aukera paregabea dela. 07. Galdetzen denean, galderak banaka egin, eta ulergarriak izan daitezen, pistak ematen s

Ugaztunetan, pertsonak barne, jakina, obulu ernaldua uteroan kokatzen den unetik ernaldia hasten da. Emakumearen ernaldiari, haurdunaldia esaten diogu, eta haurra jaiotzen denean amaituko da. Ernaldiaren iraupena ez da bera izaten espezie guztietan; pertsonarena, 9 hilabetekoa da (38-39 aste); behiarena, 40 bat astekoa; 48-49 astekoa behorrarena, eta 5 bat astekoa untxiarena. Haurdunaldia aurrera joan ahala, fetua etengabe aldatzen da harik eta behin betiko haurraren itxura hartzen duen arte. Fetuak hazteko behar dituen elikagaiak eta oxigenoa amaren odoletik jasotzen ditu. Fetua amaren uteroan buruz behera egoten da, normalean, eta likido amniotikoz beteriko zorro baten barruan, kolpe eta infekzioetatik babesteko. Gaur egun, espezialistek ekografiaren bidez egiten dute haurdunaldiaren jarraipena, fetuaren garapenean izango diren gorabehera guztien berri izateko.

Ernalketa deritzo bi zelula sexual elkartzeari. Ernalketa gertatzeko, pertsonetan, gizonezkoaren semenean dauden espermatozoideak emakumearen baginan sartu behar dute. Espermatozoideek, bagina eta uteroko pareta likatsuetatik barrena igeri eginez, Falopioren tronparaino iristen dira. Han, obuluren bat aurkitzen badute, ernaldu egingo dute. Espermatozoidea obuluaren barrura sartzen denean gertatzen da ernalketa: espermatozoide bakarra obulu bakoitzeko. Espermatozoidearen eta obuluaren nukleoak elkartuz, nukleo bakar berri bat osatzen dute. Espermatozoideak ernaldutako obuluari zigotoa edo “arrautza” deitzen zaio. Arrautza hori uterora jaisten da eta uteroaren paretari itsatsita geratzen da; hori da haurdunaldiaren hasiera. Bestalde, obulua ez bada ernaltzen, kanpora ateratzen da odol-isuri batekin. Emakumeek 28 egunetik behin, gutxi gorabehera, obulu heldu bat askatzen dute obulutegitik. Obulua ez bada ernaltzen, kanpora ateratzen da, haurdunaldirako prestatuta zegoen 

Ugalketa sexuala gerta dadin, beharrezkoa da sexu ezberdinetako zelula sexualak elkartzea (animalien kasuan espermatozoidea eta obulua). Pertsonetan, emakumezkoen eta gizonezkoen ugaltze-aparatuei dagokie zelula horiek sortzea. Irudietan ikus ditzakezu emakumezkoen eta gizonezkoen ugaltze-aparatuen eskemak.

Hona hemen Harluxet hiztegiak sexualitate hitzari ematen dion definizioa. Sexualitatea.  Sexuari dagozkion ezaugarri fisiologiko, psikologiko edo kulturalen multzoa; direlako ezaugarriekin lotuta dagoen pertsona arteko jarduera edo portaera, erakarpen fisiko gisa agertzen dena eta atsegin sexuala lortzera bideratuta dagoena. Zer esan nahi du horrek? Hona hemen zenbait puntu sexualitatearen ideia osatzen joateko, eta zuen eztabaidetarako baliagarriak izan daitezkeenak: • Sexualitatea emakumea ala gizona izatearen bizipena da. Sexualitateak badu zerikusia gorputzarekin, aldartearekin, emozioekin, norberaren bizipenekin, pertsonen artean harremanak bideratzeko moduarekin… • Sexua ez dago ezinbestean lotuta ugaltze-organoekin eta genitalekin: sexua gu geu gara, sexudunak gara, sexua gorputz barneko txoko guztietan dugu. • Pertsonaren burmuinean bizi da pertsona horren sexu-identitatea; hau da, burmuinean sentitzen da pertsonaren generoa, emakume ala gizon i

Gogoratu: gizakion bizi-funtzioak, gainerako bizidun guztienak bezala, nutrizioa, erlazioa eta ugalketa dira. Gizakiok, gure inguruarekin erlazionatzeko bi baliabide nagusi ditugu: lokomozio-aparatua eta zentzumenak. Lokomozio-aparatua Lokomozio-aparatuak higitzeko balio du, leku batetik bestera joan, inguruko gauzaren bat hartu edo beste hainbat mugimendu egiteko. Gure gorputzeko lokomozio-aparatuaren osagai nagusiak hauexek dira: muskuluak (ipurmasailak, bizepsa…), hezurrak (bizkarrezurra, femurra…) eta artikulazio edo giltzadurak . Gorputzak 206 hezur, 120 artikulazio eta 650 muskulu ditu, elkarrekin koordinatuak. Horiei esker, edozelako mugimenduak egiteko gai gara. Hezurrak . Bi funtzio dituzte hezurrek. Alde batetik, eutsi egiten diote gorputzari, eta forma ematen. Bestetik, ahulak diren organoak kanpoko erasoetatik babestu egiten dituzte. Muskuluak . Zuntzez osaturik daude eta elastikoak dira. Muskuluak hezurren gainean daude eta elkarrekin koordinatuta m

Zer jan behar da? Zure adineko ikasle batek 3.000-3.500 kilokaloria kontsumitu behar ditu egunean, eta dieta orekatu batean egunero 100 g inguru proteina, 80 g inguru koipe, 400 g inguru karbohidrato. Horrez gain, janariek dauzkaten bitaminak eta gatz mineralak kontsumitu beharko lituzke, eta ura edan.

Gizakiok digestioaren bitartez bihurtzen ditugu janariak mantenugai asimilagarri gure gorputzerako. Elikagaietatik lortzen ditugun mantenugai horiek oxigenoarekin erretzen dira zeluletan, eta errekuntza horretan sortzen da behar dugun energia. Energia horren bidez egiten ditugu ekintza guztiak. Digestioa hiru fase nagusitan bana genezake: ahoko fasea, urdaileko fasea eta hesteetako fasea . Ahoko fasea Janariak birrindu eta murtxikatu egiten dira ahoan, hortz-haginei esker. Era berean, janariak listuarekin bustitzen dira ahoan, eta elikadura-boloa sortzen da, irensteko prest. Listuaren eraginez, karbohidratoen zati bat digeritzen da, zenbait karbohidrato listuaren eraginez elikagai sinple (mantenugai) bihurtzen baita. Elikadura-boloa irensten dugunean, hestegorritik urdailera jaisten da. Urdaileko fasea Urdaila zorro kurbatu baten antzekoa da, eta han biltzen dira janariak hiru bat orduz digestioarekin jarraitzeko. Urdailaren barnealdeko guruinak urdail-urinak

Gizakion gorputza zenbait organoz, sistemaz eta aparatuz osatuta dago, eta  anatomia  deitzen zaio horiek aztertzen dituen jakintzagaiari. Gizakion organismoan dauden sistema eta aparatu nagusiak hauexek dira:  digestio-aparatua, arnas aparatua, zirkulazio-aparatua, iraitz-aparatua, lokomozio-aparatua, ugaltze-aparatua  eta koordinazio-sistemak ( nerbio-sistema  eta  sistema endokrinoa ). Sistema eta aparatu horiek hainbat organoz osaturik daude (birikak, gibela, bihotza, giltzurrunak…) eta organo horietako bakoitzak zenbait funtzio ditu. Dena dela, ezin duzu ahaztu organo horiek guztiak batera eta era koordinatuan funtzionatzen dutela; hau da, organo guztien funtzionamendu koordinatua behar dela gorputza behar bezala, eta osasuntsu, ibil dadin.

Gizakiok animalien erreinukoak gara, eta bizkarrezurra dugunez, ornodunak. Gehiago zehazten hasiko bagina, primateen ordenako ugaztunak garela esango genuke. Gizakiok eta gainerako primateek baditugu zenbait ezaugarri komun: lau gorputz adar, bost hatz eskuetan, begien kokapena (aurrerantz eta ez alboetan)… Ezberdintasunak ere baditugu: a) Gizakion buru-hezurra primateena baino ia hiru aldiz handiagoa da proportzioan. b) Gurean hatz lodia eskutik gertuago dago primateetan baino, eta, batez ere, gainerako hatzei aurrez aurre jartzeko gai da. Berezitasun horri esker, gizakiok mugimendu zehatzak egin ditzakegu eskuekin eta tresnak erabiltzeko gaitasun handiagoa dugu. c) Gizakiok bi oinen gainean gabiltza (bipedoak gara), eta primateek lau hanken gainean (ia gehienetan, behintzat). d) Ingurumena era nabarmenean aldatzeko gai gara gizakiok. Gizaki guztiok estruktura edo barne-egitura bera dugu, eta espezie berekoak gara, ezaugarri komunak izateaz gain geure artean

Munduko bizidunen dibertsitateari, eta, batez ere, munduan arriskuan dauden espeziei buruzko informazioa daukazu taulan. Datu horiek IUCN erakundeak ( Kontserbaziorako Munduko Batasuna ) egindako txostenetan oinarritzen dira. Datu horien arabera, munduan 7.480 animalia desagertzeko arrisku bizian daude, eta, erakunde horrek adierazi duenez, urtetik urtera luzatzen ari da zerrenda. ARRISKUAN DAUDEN ANIMALIAK (ESPEZIE KOPURUA) Afrika Poloen inguruak Amerika Europa Australia Asia 1.350 80 1.600 (Ipar Amerika) 1.000 (Hego Amerika) 650 700 2.100 Lehoinabarra Albatrosa Bisonte amerikarra Itsas txakur fraidea Koala Panda handia Espezie bat desagertzeko arriskuan dagoela esateko hainbat datu hartu behar izaten dira kontuan: banaketa geografikoa, populazioaren tamaina (banakoen kopurua), ugaltzeko berezitasunak, bizidunak dituen mehatxuak… Orokorrean, eta beste era batera esanda, eremu txikian bizi bada, ale gutxi badaude, berezitasun eta sents

Hauexek dira animalien bi ezaugarri nagusi: • Elkarren artean eta inguruarekin erlazionatzeko erraztasuna dute eta inguruko eraginei erantzuteko ahalmena. • Elikadura heterotrofoa dute, hots, beste bizidun batzuk janez elikatzen dira. Animaliak bi talde handitan sailkatzen dira: ornodunak eta ornogabeak. Ornodunek bizkarrezurra dute, eta barneko hezurdura; ornogabeek ez dute bizkarrezurrik, eta, izatekotan, gorputzaren kanpo aldeko babesa edo oskola dute. Animalia ornodunak Bizkarrezurra edukitzea da ornodunen ezaugarririk garrantzitsuena. Bizidunen arteko animalia ezagunenak dira ornodunak eta 45.000 espezie inguru omen daude gaur egun. Ornodunak hainbat bizimodutara eta ingurutara moldatu dira, eta horren ondorio da hainbat forma eta itxurako animalia ornodunak izatea. Gizakientzat garrantzi ekonomiko handia dute. Ornodunen artean dago ugaztunen klasea, eta horren barruan gaude gizakiok, ezin baitugu ahaztu gu ere animalia ornodunak garela, eboluzio prozesu luze b

Euskal Herrian bertako 3.400 landare-espezie loredun sailkatu dira. Horrek erakusten du landareen dibertsitatea. Honako infograman daude Euskal Herriko landareen talde nagusiak, bai landare loredunak eta bai loregabeak , eta bakoitzaren barruan ezaugarri komunak dituzten hainbat talde. Landare loredunak Landare askok loreak eta fruituak izaten dituzte. Landare horiek era askotakoak izan daitezke, bai lorearen itxuragatik, baita landarearen eiteagatik ere. Normalean bi talde handitan banatzen dira landare loredunak, lorearen arabera: •  Gimnospermoak . Landare loredunak dira, obulu eta hazi biluzikoak (obulua estaldurarik gabe egoten da, ezkata batzuen babesean). Talde horretako zuhaitz eta zuhaixken artean daude pinua, izeia, alertzea, hagina... •  Angiospermoak . Landare loredunak dira, obulua lorearen barruan babestuta eta gordeta dutenak. Landare loredun angiospermoen artean badira belarrak (garia...), landare loredun ohikoak (asuna, San Jose lorea, mitxole

Noizbehinka, perretxikoak janda intoxikatu egiten da norbait, pozoitu. Ez dira asko izaten, Euskal Herrian aspaldiko ohitura baita perretxikoak biltzea, eta jendeak, normalean, ondo ezagutzen baititu. Dena dela, urtero norbait intoxikatzen da perretxiko pozoitsuak janda. Zenbaitetan arazoa larria izan da perretxikoak jan eta pozoitzea. 1936ko gerraren ondoren, gose garaian, pozoitze asko izan ziren Euskal Herrian. Bizkaian, hamasei hil ziren 1948. urtean. Katalunian, 1972-1982 tartean berrogeita hamaika lagun pozoitu ziren eta bost hil. Perretxikoak, beraz, ondo ezagutu behar dira, arriskurik gabe jateko. Perretxikoen artean, arriskutsuenetako bat hiltzaile berdea da, Amanita phalloides espeziea. Roger Heim aditu frantsesaren datuen arabera, XX. mendean perretxikoak janda gertatu ziren 1.500 heriotzen erruduna izan zen. Horrek esan nahi du perretxiko hori benetan arriskutsua dela jateko, ondo ezagutu beharrekoa. Egia esan, Euskal Herrian, gaur egun, ez da pozoitzen j