Classify organisms using the features identified for vertebrates and arthropods.

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IGCSE Biology 0610 - 1.3 Features of Organisms

IGCSE Biology 0610 - 1.3 Features of Organisms

This section explores the key features used to classify organisms, focusing on vertebrates and arthropods. Understanding these features is crucial for placing organisms within the correct taxonomic groups.

Vertebrates

Key Features

Vertebrates are characterized by the presence of a backbone or spinal column. Other key features include:

  • Internal Skeleton: A bony or cartilaginous skeleton providing support and protection.
  • Bilateral Symmetry: Having a left and right side that are mirror images.
  • Endoskeleton: Skeleton located inside the body.
  • Head, Trunk, and Tail: Distinct body regions.
  • Brain and Spinal Cord: A centralized nervous system.
  • Gills or Lungs: For respiration.
  • Heart and Blood Vessels: A circulatory system.

Classification

Vertebrates are classified into major groups based on specific skeletal features:

Class Key Features Examples
Fish Gills for respiration, fins for locomotion, scales. Salmon, Trout, Shark
Amphibians Smooth, moist skin; undergo metamorphosis; breathe with gills and lungs. Frog, Newt, Salamander
Reptiles Scaly skin; lay amniotic eggs; breathe with lungs. Snake, Lizard, Turtle, Crocodile
Birds Feathers; wings; hollow bones; lay amniotic eggs. Eagle, Penguin, Sparrow
Mammals Hair or fur; mammary glands; breathe with lungs; give birth to live young (mostly). Human, Dog, Whale, Bat

Arthropods

Key Features

Arthropods are the largest group of animals, characterized by:

  • Exoskeleton: A hard, external covering made of chitin that provides protection and support.
  • Segmented Body: Body divided into distinct segments.
  • Jointed Appendages: Legs, antennae, and other appendages are jointed.
  • Bilateral Symmetry: Having a left and right side that are mirror images.
  • Open Circulatory System: Blood is not confined to vessels.
  • Nervous System: A ventral nerve cord and a brain.

Classification

Arthropods are classified into several major groups:

Class Key Features Examples
Insecta Three body segments (head, thorax, abdomen); six legs; usually have wings. Ant, Bee, Butterfly, Grasshopper
Arachnida Two body segments (cephalothorax and abdomen); eight legs; no wings. Spider, Scorpions, Mites, Ticks
Crustacea Two body segments (head and thorax); multiple pairs of legs; usually have a hard exoskeleton. Crab, Lobster, Shrimp, Prawn
Myriapoda Many legs; elongated body. Millipede, Centipede

Suggested diagram: A diagram illustrating the key features of vertebrates and arthropods, highlighting the differences in their skeletons, body coverings, and appendages.