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SCIENCE 6.
UNIT 4. INVERTEBRATES.
CONTENTS: 1.- Characteristics of animals and classification: Invertebrates– vertebrates. 2.– Invertebrates: characteristics. 3.- Classification: 3.1.– Sponges: sponge 3.2.– Cnidarian: jellyfish, coral 3.3.– Echinoderms: starfish 3.4.– Worms: A.– Annelids: earthworm B.– Plathelminthes (flatworms): taenia C.– Nematode: (roundworms): pinworm 3.5.– Mollusks: A.– Gastropods: snail B.– Bivalves: clam C.– Cephalopods: squid 3.6.– Arthropods: A.– Insects: wasp B.– Arachnids: spider C.- Crustaceans: prawn D.– Myriapods: scolopendra
C.E.I.P. SANTA ANA (Madridejos)
ANIMALS are multicellular and consumers. Most of them have sexual reproduction and can move.
1 There is a great variety of animals.
1.– CHARACTERISTICS OF ANIMALS & CLASSIFICATION: We can find a great variety of living beings in the animal kingdom, but they have some common characteristics like: 1.- All of them are multicellular, with tissues, organs.... 2.- All of them are consumers. 3.– Most of them have sexual reproduction. 4.- Most of them can move.
There are two main groups: invertebrates and vertebrates. A.- Invertebrates: animals without a backbone (spinal column), although some of them have a protection system like shells, or jointed plates. B.- Vertebrates: animals with a backbone. They have an internal skeleton formed by bones and a spinal column. Their body is divided in head, trunk and limbs.
ANIMALS can be:
2.– INVERTEBRATES: CHARACTERISTICS. .– Invertebrates: without a backbone. Most of animal species are invertebrates, about 97%. .– Vertebrates: with a backbone. Invertebrates have some common characteristics: 1.- They don’t have a skeleton or backbone. 3 2 2.– They are heterotroph (consumers) 3.– Most of them have a digestive cavity with one or two openings 4.- Some of them have their body protected by shells, jointed plates, hard skin…
Coral and anemones are invertebrates.
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USEFUL WORDS: .– multicellular .– consumer/heterotroph .– invertebrates .- vertebrates .– backbone / spinal column
2 C.E.I.P. SANTA ANA (Madridejos)
Water gets out of sponge
3.– CLASSIFICATION. 5 3.1.– SPONGES: They are the simplest animals. They are aquatic, and live fixed to rocks, so they can’t move. They are very soft. They filter water through their pores to get nutrients and expel it through a hole.
Structure of sponge
SPONGES: Sponges
JELLYFISH
Bell
SPONGE 6
Water gets into sponge
Adult medusa
Tentacles
Mouth/anus Mouth/anus
Oral arms with stinging cells
Larva
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8 Young medusa
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3.2.– CNIDARIANS: All cnidarians are aquatic, mostly marine, with radial symmetry. They have only one opening surrounded by sensory tentacles, so they have a nervous system. Some of them live in colonies fixed to rocks, like corals or sea anemone, and other can move like jellyfish. These animals generally reproduce asexually by budding, but there are others with sexual reproduction like jellyfish. CNIDARIANS: .– Corals, sea anemone (fixed to rocks) .– Jellyfish (can swim).
Young polyp
Jellyfish reproductive cycle: medusa and polyp periods
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Bud
3.3.– ECHINODERMS: Echino" means spiny and "derm" means skin, so they have a type of spiny structure on the skin. The body has got radial symmetry. The mouth is under the middle of the body. They can move slowly along the sea bottom looking for something to eat (they are predators). STARFISH They have tube feet to move, and a digestive system with Anus two holes. Tube feet They reproduce sexually or asexually (fission) Stomach
Tube feet Mouth
Water vascular system
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sea-urchin and sea cucumber Digestive gland
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ECHINODERMS: starfish, sea-urchin & sea cucumber
3 C.E.I.P. SANTA ANA (Madridejos)
3.4.– WORMS: They have got soft and elongated body without legs. They live in humid environment, in water or they are parasites. There are three kind of worms: Segment
A.– ANNELIDS: segmented worms. These animals are segmented worms, with no legs and no hard skeleton. They are divided in many little segments, like rings joined together. Some of them are terrestrial, but most of them are aquatic. They also have a type of closed circulatory system, and nerve system. Annelids can move around by contracting their little segments. They have two pairs of hairs on each segment that help them to move. Clitellum is for reproduction. Earthworms are hermaphrodites (each individual have males and females organs).
Clitellum
STRUCTURE OF AN EARTHWORM
ANNELIDS: Earthworm & leech 14
Anus
Esophagus Intestine
Brain
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Mouth
Leech sucking blood on a hand
EARTHWORM
Nerves
Blood vessels
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B.– PLATHELMINTHES: flatworms. Most of the species are parasites. They are flat. They can live in every environment that has water. They have a very simple nervous system. Taenia is an intestinal parasite found in countries where people eat pork. The adult worm is found in humans. It has a flat body formed by segments. It’s white in color and measures 2 to 3 metres. It has got a head (scolex) with organs to suck and fix inside the intestine. It’s hermaphrodite and produce eggs inside the segments. It is transmitted to pigs through human faeces and to humans through uncooked or undercooked pork.
Segment
Scolex
TAENIA SOLIUM 17
PLATHELMINTHES (flatworms): .- Taenia solium C.– NEMATODES: roundworms. They are round, and small (most of them, you must use under a microscope). They can live all over the place, swimming on the bottom of the ocean to inside plants and animals, and humans as parasites. They have got a complete digestive system and they have sexual and asexual reproduction. Most of them are microscopic, but there are aquatic ones very big (longer than 1 metre). Trichinosis is a disease caused by a roundworm (trichinella). Pinworms are very common inside children’s intestines. NEMATODES (roundworms): - Trichinella, pinworms...
.
Trichinella larva causes trichinosis.
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PINWORM
Pinworms from children’s intestines.
4 C.E.I.P. SANTA ANA (Madridejos)
3.5.– MOLLUSKS: They are terrestrial and marine, they have got a soft body and some of them have got a shell to protect themselves. There are three kinds of mollusks. A.– GASTROPODS: (one shell) They only have a single external spiral shell like snails. It’s made of calcium carbonate, and it’s large enough that the snail can get inside completely. Slugs don’t have any shell.
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SNAIL
Spiral Shell (Calcium Carbonate)
Head
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Mouth
Muscular foot
Anus
GASTROPODS: Snail and slug. 21
B.– BIVALVES: (two valves) They are aquatic, mostly marine, so they have gills to breathe. Muscle to move the foot
Tentacles
Respiratory pore
They live on land (so they have lungs) and in the ocean (they have gills to breathe). They have four tentacles on their heads, that they can move around, where they have sensory organs to see and touch. They also have nervous system, digestive system, respiratory system, circulatory system, excretory system and reproductive system. They can be hervivore and carnivore. Their reproduction is sexual, by eggs. They are hermaphrodite.
Eye
Gills
Slugs don’t have shell
These invertebrates have two valves (shells) that are connected by ligaments. They have got muscles to open and close the valves. Muscle to The shells are made of calcium carbonate, and they open & close are formed by the mantle (soft body wall). These the shells creatures have sensory organs, digestive system… and a foot to move and to dig in the sand. Some of them filter water to get food particles floating in the water.
Muscle to move the foot
Muscle to open & close
BIVALVES: Mussel, oyster, clam... Foot
Shell Palps
Mantle
CLAM
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C.- CEPHALOPODS: (feet on the head) They have got a head with a mouth surrounded by muscular tentacles that they use to move and hunt their preys. They have got a big brain. They are intelligent animals. They have got two eyes Systemic Branquial and other sensory organs. heart heart Ovary Tentacle They have a shell, external or internal. They can change their colour to send sigMouth nals or camouflage. They are carnivorous, and they can move expelling water like a jet (jet propulsion). They have tentacles to move and get preys. They also have an ink sac, that expels a cloud of dark ink to confuse predators. Funnel Eye Arm
CEPHALOPODS: Octopus, squid, cuttlefish...
Esophagus
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Suckers
Ink sac
Stomach
SQUID 25
5 C.E.I.P. SANTA ANA (Madridejos)
3.6.– ARTHROPODS: (arthropods means jointed or articulated legs) They have an external skeleton, segmented body and jointed legs . They can be terrestrial or marine. A.– INSECTS: 26 Insects are invertebrates that have an exoskeleton made of chitin. They have a three-part body (head, thorax and abdo6 legs men). On the head, they have two compound eyes and two antennae. They have six legs (under the thorax) and several species have four wings to fly. They have a ‘tracheal system’ (net of tubes) to breathe. Insects go through a metamorphosis. This is a complete change in body structure. Butterflies start as eggs, change into caterpillars (larva). Later they’ll enter an inactive state called pupa or chysalis, and finally emerge as an adult. Abdomen: . Insects are mostly solitary, but some of them (bees, 27 Intestines, tracheas ants and termites) are social and live in colonies. and reproductive system.
2 pair of wings
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WASP 2 antennae (sense organs)
2 compound eyes
Mouth
Thorax: Where legs and wings are joined.
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Head: 2 eyes 2 antennae Mouth
INSECTS: ants, bees, wasps, flies, butterflies... METAMORPHOSIS OF INSECTS:
SILKWORM
The female butterfly lays hundreds of eggs.
A small caterpillar goes out from the egg.
4.- BUTTERFLY (adult)
The pupa changes into a BUTTERFLY, that goes out of the cocoon.
3.- PUPA or CHRYSALIS
SILKWORM LIFE CYCLE
1.- EGG
2.- LARVA (Caterpillar)
The caterpillar eats mulberry leaves and gets bigger and bigger.
Inside the cocoon, the Caterpillar changes into a PUPA or CHRYSALIS
The caterpillar builds a cocoon of silk.
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B.– ARACHNIDS:
They are terrestrial, and they have a tracheal system to breathe. Their body has a cephalothorax and abdomen. All arachnids have eight legs. They don’t have antennae, but they have compound eyes. They are carnivorous. They have a pair of chelicerae for feeding and defense (they can inject venom), and another pair of pedipalps for feeding, locomotion and reproduction. Spiders produce silk, and many of them build a net to capture preys. When an insect is trapped on the net, the spider injects it some liquids with the chelicerae to dissolve its soft parts that the spider will suck. Scorpions have a tail formed by segments. In the last one contains a stinger with venom to kill preys. They also have a pair of pincers to catch the prey and immobilise it.
abdomen
cephalothorax
8 walking legs
eyes
2 pedipalps
2 chelicerae
SPIDER
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33 abdomen
stinger
cephalothorax pincer
Tail (6 segments) 8 legs
ARACHNIDS: spider & scorpion.
SCORPION 34
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eye pedipalp
chelicerae
C.– CRUSTACEANS: Most of them live in the water, so they’ll have gills. They have got 10 jointed legs, two antennae, and two pincers that they use to pick up food, for intimidating and defence. They have got body segments formed by hard shields used for protection. They mould the exoskeleton to grow. Their body is formed by head, thorax and abdomen. Sometimes the head and thorax are fused forming a cephalothorax, covered by a carapace. They eat particles floating around the ocean, they don’t hunt preys. Most of them have a sexual reproduction. First, eggs that transform into larvae and finally into adults. 36
carapace (covers the cephalothorax)
PRAWN
rostrum
PILLBUG
Eye stalk eye
abdominal segments
37 claws or pincers
38 antennae
eye
CRAB antennae
walking legs walking legs Swimmerets (Legs for swimming)
telson
uropods
CRUSTACEANS: crabs, crayfish, prawn, shrimp, lobster… pillbug
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40
carapace
7 C.E.I.P. SANTA ANA (Madridejos)
D.– MYRIAPODS: They are terrestrial, they are covered by chitin that makes the exoskeleton very hard. They are formed by segments, with a pair of legs per segment. They mould the exoskeleton to grow. Myriapods breathe through spiracles that connect to a tracheal system similar to insects. They also have two antennae and two eyes. They have got sexual reproduction. MYRIAPODS: scolopendra or centipedes, millipedes... Centipedes (means a hundred feet). They are elongated creatures with one pair of legs per body segment. Despite the name, centipedes can have from 30 to 384 legs. They have a pair of venom claws formed from a modified first appendage. Centipedes are fast, carnivorous and venomous, hunting mostly at night. Size can range from a few millimetres to the giant scolopendra (about 30 cm in Venezuela)
2 antennae
segments
head
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MILLIPEDE
2 antennae
Venom claws
2 legs pers segment
SCOLOPENDRA
Millipedes (means a thousand feet). Most millipedes are slower than centipedes, and feed on leaf litter and detritus.. They are distinguished by the fusion of each pair of body segments into a single unit, giving the appearance of having two pairs of legs per segment. They typically
head
have between 36 and 400 legs. 2 pair of legs per segment
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ARTHROPODS
Antennae Legs
Examples of animals Ants, bees, wasps, flies, butterflies...
Parts of the body
A.- INSECTS (Terrestrial or aquatic)
2
6
B.- ARACHNIDS (Terrestrial)
No
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Spiders Scorpions
Cephalothorax .- Tracheal system (respiration) Abdomen .- Carnivorous .- 2 Chelicerae and 2 pedipalps
2
10
prawn, shrimp, lobster…
Cephalothorax .- They mould the exoskeleton to grow: And egg - larva - adult Abdomen
C.-CRUSTACEANS (Mostly aquatic)
Head Thorax Abdomen
Characteristics: .– Jointed legs .– Exoskeleton made of chitin .- Thracheal system (respiration) .- Metamorphosis: egg - larva - chrysalis - adult
.- They eat particles floating around the ocean Crabs Terrestrial D.- MYRIAPODS (Terrestrial)
Carapace
Pillbug. 2
More Scolopendra than Millipedes 10
Head Body (formed by segments)
.– 2 Legs per segment. .– Tracheal respiration