edlc 2nd. year. animal kingdom: spiders- leonel

SPIDERS

How many species of spiders are there in the world?

• ORDER ARANEAE: SPIDERS• THE SPIDERS ARE A LARGE GROUP OF 35.000

RECOGNISED SPECIES

WHERE ARE SPIDERS DISTRIBUTED?

• THEY ARE DISTRIBUTED ALL OVER THE WORLD.

Spiders trapping the dam

• ALL SPIDERS ARE PREDACEOUS AND FEED LARGELY ON INSECT

WHEN ARE THE SPIDERS ARE IN GROUP?

• Some spiders chase their prey, others ambush them , and many trap them in a net of silk.

RESPIRATORY SYSTEM OF SPIDERS

• SPIDERS BREATHE BY MEANS BOOK OF LUNGS (MANY PARALEL EAR POCKET) OR TRACHEAE (SYSTEM OF AIR TUBES THAT CARRY AIR DIRECTLY TO THE SPIRACLES).

EYES

• SPIDERS USUALLY HAVE 8 SIMPLE EYES. THEY ARE USED FOR PERCEPTION OF MOVING OBJECTS.

THE WEB

• THE ABILITY TO SPIN SILK IS AN IMPORTAT FACTOR IN THE LIVES OF SPIDERS. SPIDERS HAVE SPECIAL GLANDS THAT EMIT A LIQUID THAT HARDENDS ON CONTACT WITH AIR TO FORM THE SILK THREAD. THESE THREADS WILL STRETCH BEFORE BREAKING. THE SPIDERS WEB VARIES WITH THE SPECIES. BY SENSING THE VIBRATIONS OF ITS WEB THE SPIDERS CAN JUDGE THE SIZE OF ITS PREY.

DOES THE MALE SPIDER fertilize the female?

• BEFORE MAITING, THE MALE SPINS A SMALL WEB, DEPOSITS A DROP OF SPERM , ON IT , THEN IT PECKS IT AND STORES IN A SPECIAL CAVITY. THE FEMALE LAYS FERTILIZED IN A SILKEN COCOON WHICH CAN CONTAIN HUNDREDS OF EGGS.

ARE ALL SPIDERS POISONOUS?

• THEY HAVE POISONOUS GLANDS, WITH WHICH THEY DISPATCH THEIR PREY.

ARE SPIDERS REALLY DANGEROUS?

• SPIDERS ARE TIMID CREATURES,THE VENOM PRODUCED TO KILL THE PREY IS USUALLY HARMLESS TO HUMANS.

• SPIDERS BITE WHEN THREATENED OR WHEN DEFENDING THEIR EGGS.

• THERE ARE HOWEVER , SOME SPIDERS THAT CAN GIVE SEVERE OR FATAL BITE;SUCH AS THE BLACK WIDOW AND THE BROWN RECLUSE.

• ANIMAL DIVERSITY• BY: HITMAN AND ROBERT

• LEONEL ARRIAGADA• 2° 2°

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