22 2.1 Different kinds of animals 1. Unicellular animals do not have any tissues and organs. Which parts of these animals perform the necessary life processes? 2. Who are amoebae named after and why? 3. One of the characteristics of life is reproduction. Why do unicellular and bilayered animals just split themselves up when they reproduce? 4. Read the extension box ‘How do amoebae move?’. Use this information to show, using three sequential drawings, how an amoeba catches its food. The cell organelles After the Greek God Proteus. He was able to change shape. Unicellular and bilayered animals do not have specialised organs for reproduction. The teacher checks the drawings. This is an example of a correct drawing.
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2.1 Different kinds of animals - degoedeman.nl · 22 2.1 Different kinds of animals 1. Unicellular animals do not have any tissues and organs. Which parts of these animals perform
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2.1 Different kinds of animals1. Unicellularanimalsdonothaveanytissuesandorgans.Whichpartsof
theseanimalsperformthenecessarylifeprocesses?
2. Whoareamoebaenamedafterandwhy?
3. Oneofthecharacteristicsof life isreproduction.Whydounicellularandbilayeredanimalsjustsplitthemselvesupwhentheyreproduce?
What do you need?• Dissectingpanordissectingboard• Latexgloves• Forceps(optional)• Dissectingscissors• Dissectingscalpel(optional)• Probe• Teasingneedle• Petridishwithwater• Stereomicroscopeormagnifyingglass• Smallfish(likesardine)ortheheadofabigfish(likemackerel)
What do you have to do?1. Openthemouthofthefishbypushingthelowerjawdown.
Depends on the kind of fi sh. The teacher should check the answer.
One.
Only on one side.
Because then the gill fi laments attached to the gill arches will
unfold.
In the water, because then the fi laments are unfolded.
a. Howmanygillarchesdoesyourfishhave?
b. Athowmanyplacesarethegillarchesattachedwitheachother?
c. Wherearethegillarchesattachedtoeachother?
d. Thegillarchisbestobservedwhileitisinwater.Whyisthis?
e. Whenisthesurfaceareaofthegillarchlarger?Whenitisinthewa-terorwhenitisoutofthewater.Explainyouranswer.
Visit the site www.ovdbricks.nl for more dissection on fi sh. Play the digital game and answer the questions.
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2.5 Sensing the environment
29.What is the main reason that organisms must sense their environ-ment?
30.Readthesentencesbelowandchoosethebestanswer.
a. Birdsofpreydependonsight/hearingwhilehunting. b. Catsseemore sharply/lesssharplythanhumans. c. Becauseofaspeciallayerintheireyes,catscan/cannotseeinthe
dark. d. Manyreptilesandamphibianshaveathirdeyetosee colour/dif-
ferences in dark or light. e. You are/a kestrelisabletoseethissentenceatarangeof23me-
Big TalkersEarth’s largest land animals have a lot to say, even when they don’t seem to be making a sound.
Thirsty and hot, 12 elephants plod across the fried African landscape. The water hole is less than a mile away now, and everyone in the herd is looking forward to a good, long drink. Tired calves want to stop, but mothers and aunts nudge them along. The older animals make soft, soothing noises. “We’re almost there,” they seem to say. “Just keep walking.”
Suddenly everyone stops. Huge ears stretch out like satellite dishes. After a minute or two of what seems like silence, the animals turn and walk away from the water hole, fast. As they go, the adults huddle close to the calves.
So what happened? Why did the elephants change their course? They seemed to be listening to something. And whatever it was, they got the message to flee! Yet human ears heard nothing.
Elephants make plenty of sounds that humans can hear, such as barks, snorts, roars, and trumpet-like calls. Often a herd will use such sounds to talk with other elephants. But they weren’t in the air this time.
Second LanguageFor years, elephants puzzled observers with this type of behaviour. But now scientists have solved the mystery. They discovered that elephants have a “secret” language they use for communicating over long distan-ces.
This special talk is based on infrasound, sounds so low in pitch that humans can’t hear them. The sounds can travel for several miles, allo-wing the six-ton animals to keep in touch across grasslands and forests in Africa or Asia.
Translating infrasound helps scientists begin to understand elephant behaviour. For example, it turns out that the elephants heading to the water hole may have heard warning calls from another herd. Perhaps a lion was slurping water and looking hungry. The cat would be no match for an adult elephant, but it might kill a calf. No drink would be worth that risk, so the herd turned away.
Questions
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SOURCE 1
Long-Distance CallsElephants use infrasound to communicate many types of messages over long distances. Some of their talk helps hold families together. To under-stand how this works, you need to know a little about elephant families.
Females spend their lives with mothers, sisters, and children. They form tight-knit herds of 10 to 20 members. The oldest female elephant, the matriarch, takes charge. Males live with a herd until they are teenagers. Then they depart, living alone or joining with other males in a “bachelor herd.”
The members of a herd often scatter over large areas to seek food for their mighty appetites. (An adult elephant can eat 136 kilos of grass and plants in a single day!) Long-distance calls let elephants know where their relatives are. And when the matriarch says, “Come here!” the herd gathers within minutes.
Like curious kittens, elephant calves sometimes wander off and get into trouble. When that happens, they cry for help. Adults respond with in-frasound calls and other noises: “It’s okay. We’re coming to help you.”
Adult males and females often live far apart, so they use infrasound to find each other at mating time. Females mate only once every four years or so. When a female is ready, she makes a special series of calls. Males who hear the calls storm toward her. Sometimes two or more males bat-tle fiercely for a chance to court the female.
Hearing AidsElephants tune in to all this talk with their large, powerful ears. An African elephant’s ear can grow to be six feet long and four feet wide. (Asian elephants have much smaller ears.) When straining to hear some-thing, the animal turns toward the sound and opens its ears wide.
At the same time, the elephant may raise its trunk to sniff at the wind. Elephants have a keen sense of smell. Odours may help them figure out what they’re hearing.
Elephants may have yet another way of learning what’s going on around them. Although scientists haven’t proved it, some think elephants can actually feel infrasound as the sound waves travel through the ground.
Source: Winkler, P (September 2001). Big Talkers, National Geographic Explorer, p. 4-7.
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Questions
a. “Earth’slargestlandanimalshavealottosay,evenwhentheydon’tseemtobemakingasound.”Explainthissentence.
b. Whatkindofsoundsdotheelephantsmaketocommunicatewitheachotherwithintheherd?
c. Whatisthe‘secret’languagethatelephantsuse?
d. Translatingthissecretlanguagehelpsthescientistunderstandelephantbehaviour.Writedownanexamplegiveninthearticletoexplainthis.
e. Longdistancecommunicationhelpsholdelephantfamiliestogether.Givethreeexamplesthatprovethis.
Elephants produce infrasound. This is sound we cannot hear but
elephants can.
Infrasound, barks, snorts, roars, and trumpet-like calls.
Communication through infrasound.
For example, it turns out that the elephants heading to the water
hole may have heard warning calls from another herd. Perhaps a
lion was slurping water and looking hun-gry. The cat would be no
match for an adult elephant, but it might kill a calf.
No drink would be worth that risk, so the herd turned away.
The members of a herd often scatter over large areas to seek food for their mighty appetites. (An adult elephant can eat 136 kilos of grass and plants in a single day!) Long-distance calls let elep-hants know where their rela-tives are. And when the matriarch says, “Come here!” the herd gathers within minutes.
Like curious kittens, elephant calves sometimes wander off and get into trouble. When that happens, they cry for help. Adults respond with infrasound calls and other noises: “It’s okay. We’re coming to help you.”
Adult males and females often live far apart, so they use infrasound to find each other at mating time. Females mate only once every four years or so. When a female is ready, she makes a special series of calls. Males who hear the calls storm toward her. Sometimes two or more males battle fiercely for a chance to court the female.
Questions
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f. Which three hearing aids does an elephant use to know where thesoundiscomingfrom?
g. Gotowww.ovdbricks.nl.LookunderBiology,chapter2,sources.Openthelink‘Thelostelephant’,andplaythegame.Doyouknowenoughaboutelephantsandtheirwaysofcommunication?
a. TadpolesoftheAmericantreefrogundergoatransformationwhenpredators,likedragonflynymphs,arepresent.Onepartofthetrans-formationhastodowithgrowth,anotherpartwithdevelopment.Writedownwhichhastodowithgrowthandwhichwithdevelop-ment.
b. What is the advantage the transformed tadpoles have over thenymphs?
46.Whydoinsectlarvaehavetomoult?
The larvae of newts do not undergo complete metamorpho-sis,
tadpoles do.
Growth: they grow bigger.
Development: they get red tails.
They are faster than the nymphs
Because their exoskeleton, or skin, does not grow with them.