INVERTEBRATES. The Earth and Living Things. Carme Font Casanovas 1

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1 INVERTEBRATES Living Things. Carme Font Casanovas 1

2 How many animals can you see? ant rose coral snake anemone fish grass bee Living Things. Carme Font Casanovas 2

3 Invertebrates There are animals without either a backbone or an internal skeleton. This group includes the Giant Squid at 18m long gall mites, which are less than 25 mm long. They can be found in most habitats. There are between 3 million 15 million species in the world. About 97% of creatures on Earth are invertebrates. Living Things. Carme Font Casanovas 3

4 In this unit we will learn Invertebrates Characteristics Classification Body Nutrition Reproduction Respiration Movement Annelids Arthropods Molluscs Cnidarians Echinoderms Sensory Systems Living Things. Carme Font Casanovas 4

5 ANNELIDS They are usually called worms. Their body is soft long, made of rings or segments. They can live on the l or in the water. earthworm nereis Living Things. Carme Font Casanovas 5

6 ARTHROPDS Their body has an exoskeleton. The exoskeleton protects their organs inside. They have jointed legs segmented bodies. They are the largest invertebrate group (75% of all animal species). Insects, arachnids, crustaceans myriapods are arthropods. Living Things. Carme Font Casanovas 6

7 Insects An insect's body is made up of thorax. head abdomen Living Things. Carme Font Casanovas 7

8 Insects Insects have six jointed legs. Many insects have wings these are also attached to the thorax. Living Things. Carme Font Casanovas 8

9 Insects An insect has a pair of antennae on its head a pair of compound eyes. Living Things. Carme Font Casanovas 9

10 Myriapods Myriapod means 'many-legged one'. They can have anything between about pairs of legs. Most of them live in dark, damp places. Living Things. Carme Font Casanovas 10

11 Myriapods They have lots of segments to their body Centipedes have one pair of legs per body segment. Millipedes have two pairs of legs per body segment.? Living Things. Carme Font Casanovas 11

12 Arachnids They have eight legs. Arachnids include spiders, scorpions, mites ticks. Living Things. Carme Font Casanovas 12

13 Arachnids Arachnids have two parts to their body - the cephalothorax the abdomen. The cephalothorax = head thorax. It contains the legs, mouthparts sense organs. The abodomen contains the main organs, just like insects. Living Things. Carme Font Casanovas 13

14 Crustaceans They have: a hard exoskeleton five pairs of legs or more. one or two pairs of antennae. crab lots of crustaceans live in water. shrimps woodlouse lobster Living Things. Carme Font Casanovas 14

15 MOLLUSCS Their body is soft. Some have shells to protect their body. Many molluscs live in the water. snail slug shellfish mussel squid octopus Living Things. Carme Font Casanovas 15

16 CNIDARIANS This diverse group of very simple-bodied animals. All they have is a stomach a mouth surrounded by tentacles. It includes sea anemones jellyfishes. Living Things. Carme Font Casanovas 16

17 ECHINODERMS They have a soft body encased in a hard rigid shell. Many echinoderms have spines covering their shell. They live on the s or rock ocean bottom. It includes the sea urchins starfishes. Living Things. Carme Font Casanovas 17

18 NUTRITION Some of them have a very simple digestive system they can feed themselves with nutritive particles from the soil or dissolved in water. E.g. Earthworms mussels. Living Things. Carme Font Casanovas 18

19 NUTRITION Some invertebrates are herbivores. e.g. Snails many insects ( grasshoppers, bees, butterflies...). Living Things. Carme Font Casanovas 19

20 NUTRITION Some are carnivores. e.g. Octopus, praying mantis, jellyfish, sea anemones, starfish. Living Things. Carme Font Casanovas 20

21 NUTRITION Some invertebrates eat plants meat. They are omnivores. e.g. Ants Living Things. Carme Font Casanovas 21

22 RESPIRATION Invertebrates can present three types of respiration: - with a kind of lung ( terrestrial snail only) - with gills (some which live in water) - through the skin, (worms) - tracheal system, (arthropods) Terrestrial snails are the only ones that have a kind of lung. Living Things. Carme Font Casanovas 22

23 Tracheal system Insect s trachea is a network of tiny tubes that go throughout the insect s body. These tubes connect each cell of the body to the outside, through holes in the abdomen. So, the cells get oxygen directly from the outside air. Living Things. Carme Font Casanovas 23

24 REPRODUCTION The invertebrates present two types of reproduction: Sexual. Asexual. Living Things. Carme Font Casanovas 24

25 Sexual reproduction All of them are oviparous. They come from eggs, laid by their mothers. Most of them are unisexual. They are males or females. Some are hermaphrodite. Each animal has two sexes. Living Things. Carme Font Casanovas 25

26 Development The development can be direct or indirect. In a direct development, the young has the form of an adult. e.g. squid. In an indirect development the young hasn t the form of an adult. It has a metamorphosis (change). Living Things. Carme Font Casanovas 26

27 Metamorphosis Complete Living Things. Carme Font Casanovas 27

28 Metamorphosis Incomplete Living Things. Carme Font Casanovas 28

29 Asexual Reproduction Fragmentation Living Things. Carme Font Casanovas 29

30 Asexual Reproduction Budding cnidarians Living Things. Carme Font Casanovas 30

31 MOVEMENT Invertebrates move in different ways depending on which group they belong to where they live. Flying. Hopping. Walking. Slithering By expelling water from their bodies. With a row of adhesive suckers. Living Things. Carme Font Casanovas 31

32 SENSORY SYSTEMS Both squid octopus: have excellent eyesight. Their senses of touch, taste smell are highly developed can detect movement up to about 30 meters away. Snails have 2 pairs of tentacles. The longest ones with eyes. The shortest with sense of touch. Living Things. Carme Font Casanovas 32

33 SENSORY SYSTEMS Arthropods ( insects, centipedes,...) They have eyesight. Their antennae are their sense of smell, taste touch. eyes antennae Living Things. Carme Font Casanovas 33