Invertebrates and Vertebrates Invertebrates 1 Body symmetry Some

Invertebrates and Vertebrates

Invertebrates

1. Body symmetry • Some are asymmetrical e. g. sponges • Radially symmetrical e. g. jelly fish, starfish • Bilaterally symmetrical e. g. snail, sea hare

2. Segmentation • Body of animals divided into sections or segments • Insects have three segments – head, thorax and abdomen • Earthworm, marine worms

3. Support of the body • • Support and protection Sponge – body is supported by jelly like material Roundworms have thick skin Crab and lobsters have exoskeleton

4. Respiratory and circulatory systems • • Respiratory system – exchange of gases Respiration requires oxygen E. g. gills in lobsters Tracheae (network of tubes) in insects • • • Circulatory system - transport substances Closed circulatory system – fluid inside tubes E. g annelids (earthworm) Open circulatory system – fluid moves in open spaces of body E. g. mollusks (snail)

5. Digestive and excretory systems • Digestion – conversion of food from large particles/molecules to smaller ones • After consumption, food is digested and simpler molecules are transported to cells • Oxidation of food in cell (cellular respiration) produces energy • Invertebrates have relatively simple digestive systems

6. Digestive and excretory systems • Excretory system – get rid of the waste materials • As body uses nutrients and performs reactions, wastes are formed • Excretory system eliminates these wastes along with excess of water • In some invertebrates, the digestive system removes wastes • In others, there is a separate excretory system

7. Nervous system • Nervous system – sense and respond (process information) • Receive and send electrical signals that control functions of the body • Several invertebrates have a specialized area called “brain” • Brain acts a control center • In addition to brain, sense organs are also present • Sense organs collect information (e. g. light)

Nervous system

8. Reproduction • Budding (e. g. hydra) • Fragmentation (e. g. planaria) • Sexual reproduction (e. g. insects)

9. Development • Development – various stages of life • Metamorphosis – series of developmental changes in the life cycle (insects) • Many insects reproduce sexually and lay eggs • The insect hatched from egg and undergo various distinct stages of life cycle • Metamorphosis (two types) – Complete metamorphosis - 4 stages (Egg Larva Pupa Adult) – Incomplete metamorphosis – 3 stages (Egg Nymph Adult)

Development

Development • Incomplete metamorphosis

Vertebrates

Vertebrates • • • Land, fresh water, oceans Swim, crawl, burrow, hop, fly Have a backbone Head (brain, sensory organs) Presence of cartilage (and replacement by bone during development)

1. Body symmetry • All are bilaterally symmetrical • Head is distinct from rest of the body • Four regions of body (dorsal, ventral, anterior, posterior)

2. Body coverings • Body is covered by skin • Protection from outer environment • Varies in structure – Reptiles (scales), fish (scales), – Mucus in amphibians and fish – Birds (feathers), mammals (fur, hair) • Help maintaining body temperature • Colors and patterns (camouflage and recognition)

Body coverings

3. Support of body • • Presence of endoskeleton Skull, backbone, limb bones Skull (brain), vertebrae (spinal cord) Attachment of muscles – movement

4. Respiratory system • Breathing and exchange of gases • Two types of systems – gills (water) and lungs (land) • Presence of blood vessels in these organs

5. Circulatory system • • • Transport of materials Closed circulatory system Blood, vessels and pump (heart) Arteries, veins and capillaries Heart pumps blood Oxygenation (gills/lungs) Carbon dioxide removal Nutrients and other substances Waste removal (kidneys)

6. Digestive and excretory systems Digestive tract – long tube like digestive system Direct swallowing and chewing Food passes on to stomach (acid and enzymes) Small intestine (absorption of nutrients , blood vessels present) Large intestine (water absorption, undigested material is converted to faeces) • Nitrogenous (urea) and other wastes • Kidneys combine wastes with water to produce urine • • •

Digestive and excretory systems

7. Nervous system • • • Processing information (sense and respond) Electrical signals Brain control center, spinal cord and nerves Sensory organs Sensory nerves (body to brain), motor nerves (brain to body) Size of brain and learning

8. Reproduction and development • • • Sexual reproduction Fertilization - male (sperm) and female cells (egg) Fertilized egg divides to produce multicellular stage Differentiation of cells (specialization) Different cells perform different function

9. Reproduction and development • Amphibians and some fish – larva hatches in water, develops into an adult organism • Reptiles, birds and mammals do not have larval stage • Embryo is protected by membranes • Eggs of reptiles, birds and some mammals have a shell • Most mammals do not lay eggs (give birth to offspring) • Offspring develops inside the body of female individual • Embryos of different species are similar to each other at early stages of development • Embryos begin to look more like the adults of their own species as they develop

Reproduction and development

10. Parental care • • Number of offspring and parental care Birds and mammals have few offspring Feeding and protection Parental care increases chances of surviving