UNIT 9. THE ANIMAL KINGDOM: INVERTEBRATES 1. The simplest invertebrates 2. Annelids, molluscs and echinoderms 3. Arthropods 4. Insects
All living beings belong to the Animal Kingdom have got the following characteristics: 1. They are MULTICELLULAR beings. 2. They have got EUKARYOTIC cell structure 3. They are HETEROTROPHIC origanisms There are two groups of animals: INVERTEBRATES AND VERTEBRATES. The main difference between invertebrate and vertebrate animals is that invertebrates don t have spinal column and vetebrates do. More than 95% of animal species are invertebrates, which have only one characteristic in common: they don t have spinal column (backbone) or internal skeleton.
There are EIGHT GROUPS OF INVERTEBRATE ANIMALS: 1. SPONGES OR PORIFERA (esponjas o poríferos) 2. COELENTERATA (celentéreos) 3. FLATWORMS (platelmintos o gusanos planos) 4. NEMATODES (nematodos o gusanos cilíndricos) 5. ANNELIDS (anélidos) 6. MOLLUSCS (moluscos) 7. ECHINODERMS (equinodermos) 8. ARTHROPODS (artrópodos)
1. THE SIMPLEST INVERTEBRATES
SPONGES OR PORIFERA (esponjas o poríferos)
COELENTERATA (celentéreos) Polyps Corals Jellyfish Sea anemones
FLATWORMS (platelmintos o gusanos planos) Planaria Tapewarms
NEMATODES (nematodos o gusanos cilíndricos) Whipworms Tapeworms (oxiuros) Anisakis
2. ANNELIDS, MOLLUSCS AND ECHINODERMS Annelids (anélidos) CHARACTERISTICS: 1. They are more developed worms with a digestive tract, circulatory system and excretory organs. 2. Their bodies are composed of segments or rings.
THE MOST COMMON ANNELIDS ARE: 1. LUGWORMS (gusanos arenícolas) which live in the seabed, hide in holes in the sand or in tubes. 2. EARTHWORMS (lombrices de tierra) which live in the soil and feed on decomposing waste. 3. LEECHES (sanguijuelas) which live in fresh water and feed on blood from the host.
Molluscs (moluscos) CHARACTERISTICS: 1. Soft-bodied animals that are usually protected by a shell. 2. They have highly developed sensory organs.
THE MOST IMPORTANT GROUPS ARE: 1. GASTROPODS (gasterópodos) which have a foot, a head with tentacles and eyes, and usually covered by a shell. They move by crowling. Examples: snails (with a spiral shell), slugs. 2. BIVALVES (bivalvos) which don t have a head and their bodies are protected by a shell made up of two pieces called valves. Examples: mussels, clams. 3. CEPHALOPODS (cefalópodos) which have an inner shell, sophisticated eyes and tentacles with suction cups to grip their prey. Examples: octopus, cuttlefish and squid.
Octopus Cuttlefish Squid
Echinoderms (equinodermos) CHARACTERISTICS: 1. They have radial simmetry and an external skeleton consisting of rigid plates. 2. They have an ambulacral apparatus to move. Examples: starfish, sea urchins and sea cucumbers.
Starfish Sea urchin Sea cucumber
3. ARTHROPODS Artrópodos significa patas articuladas ) CHARACTERISTICS: 1. Their body is divided into three parts: head, thorax and abdomen. 2. They have jointed appendages such as legs, antennae, wings and mouthpart (mandibles, claws or pincers). 3. They have developed sensory organs, located mainly in the head. 4. Arthropods are protected from predators by an exoskeleton. They grow through a process called moulting that occurs several times during their lives.
Groups of arthropods 1. ARACHNIDS 2. MYRIAPODS 3. CRUSTACEANS 4. INSECTS
ARACHNIDS (arácnidos) CHARACTERISTICS: 1. Their body is divided into two parts: the cephalothorax (a fusion of the head and thorax) and the abdomen. 2. They have four pairs of legs, two pedipalps (appedages) and two chelicerae connected to a poison gland to grip their prey. 3. They don t have antennae or mandibles. Examples: spider, scorpion, tick and mite.
Spider Scorpion Tick (1-10 mm long) Mite (0,1-0,8 mm long)
MYRIAPODS (miriápodos) CHARACTERISTICS: 1. Their body is made up of many articulated rings, with one (centipedes) or two (millipedes) pairs of legs on each segment. 2. They have eyes and antennae (on their heads). Examples: centipedes and millipedes.
Centipedes (escolopendra, from 21 to 23 rings) Millepedes (most with more than 20 rings, from 34 to 400 legs)
CRUSTACEANS (crustáceos) CHARACTERISTICS: 1. Their body is divided into two parts: the cephalothorax and the abdomen. 2. Their skeleton is hardened with calcium salts. GROUPS: - Lower crustaceans that form zooplancton. - Higher crustaceans, which have 5 pairs of legs, 2 pairs of antennae and several pairs of mouthparts. Examples: prawn, lobster and crab.
Prawn Lobster Crab
CHARACTERISTICS: 1. Their body is divided into three parts: head, thorax and abdomen. 4. INSECTS (The biggest group of arthropods and animals) 2. They have three pairs of legs extend from the thorax and can serve to jump, walk, swim or dig. 3. They have a pair of antennae, one or two or no pairs of wings, eyes and several mouthparts adapted to different types of food. Most insects have four wings. Some insects have independent wings (dragoflies), others have wings that are joined together (butterflies), others have hardened wings to protect their bodies (beetles) and others don t have wings (ant). Examples: grasshopper, fly, butterfly, bee, wasp, ant, beetle, dragonfly
Butterflye Ant Beetle Dragonfly (libélula) Wasp Grasshopper Fly
La METAMORFOSIS es un proceso biológico, característico de los insectos y anfibios, mediante el cual un animal pasa por diferentes etapas desde su nacimiento hasta la edad adulta. En algunos insectos, estas etapas son la LARVA, PUPA Y ADULTO, mientras que en otros insectos son la NINFA Y ADULTO.
Activity 10 on page 88. Activity 11 on page 89. Activities on page 91.
VOCABULARY 1. PORIFERA, SPONGES, osculum, COELENTERATA, polyps, sea anemones, corals, jellyfish, free living animals, irritating fluid, worm, FLATWORMS, planaria, tapeworms, NEMATODES, roundworm, whipworm. 2. ANNELIDS, lugworms, earthworms, leeches, prey, host, MOLLUSCS, soft-bodied, shell, gastropods, bivalves, cephalopods, crawling, snail, slug, mussles, clams, suction cup, grip, octopus, cuttlefish, squid, ECHINODERMS, radial simmetry, rigid plates, ambulacral apparatus, starfish, urchin, sea cucumber. 3. ARTHROPODS, jointed appendages, wing, mouthparts, exoskeleton, moulting, ARACHNIDS, MYRIAPODS, CRUSTACEANS, INSECTS, poison gland, spider, scorpion, tick, mite, centipedes, millipedes, prawn, lobster, crab, grasshoper, fly, butterfly, bee, wasp and beetle.