UNIT 5: VERTEBRATE ANIMALS

UNIT 5: VERTEBRATE ANIMALS

1. GENERAL CHARACTERISTICS

   • Vertebrates are multicellular, eukaryotic, heterotrophic organisms that have a backbone (spinal column) is made of articuñated segments of bone known as vertebrate.
   • The body structure of a vertebrate
     • -Has bilateral simmetry and is divided into three parts: head, trunk and tail. -The body is covered in skin. It can also have different types of associated glands. -All have internal skeleton made up of a skull and a backbone. REGULATION OF BODY TEMPERATURE Fish, amphibians and reptiles are ecotherms. Create very little of their own body heat and relyon heat from their enviroment to regulate their body temperature. Birds and mammals are endotherms. Mantain a constant internal temperature.
   • Vital functions of vertebrates
     • NUTRITION: have a complete digestive system. There are herbivores, carnivores, omnivores and also filter-feeders. Breathe through gills or lungs. Some also breathe through their skin. For example in frogs the larvae breathe through gills, whereas the adults do it through lungs. REPRODUCTION: Reproduce sexually and most have separate sexes, except some fish species which are hermaphrodites. Vertebrates can be oviparous (lay eggs), ovoviviparous (eggs develop inside the mother´s body until they are ready to be hatched) or viviparous (the embryo develops into a young animal inside the mother´s body).  Oviparous: female lay eggs in the open environment which reduces the chances of survival for the offspring. Viviparous: the pprtection of the embryo inside the mother body increases the chances of survival for the young. INTERACTION: nervous system is made  up of a spinal cord, which runs along the animal´s back, and a highly developed brain, located in the head. CLASSIFYING VERTEBRATES Fish: verebrate with gills, scales and fins. Birds: vertebrates with feathers, beaks and wings. Amphibians: vertebrates with a soft skin and four legs. Reptiles: vertebrates with a hard skin covered in scales and four legs. Mammals: vertebrates with four limbs and mammary glands.

2. FISH

   • Are aquatic animals that live in marine and freshwater environments. Have a fusiform body with fins that help them to swim. the body is covered in scales. The body of a fish is divides into a head, trunk and tail.
   • VITAL FUNCTIONS OF FISH
     • NUTRITION: Some are carnivores others herbivores or omnivores. Larvae are usually filter-feeders. Fish breathe through gills. Are protected by a operculum or gill cover. REPRODUCTION: have separated sexes. Most are oviparous and their fertilisation is external. Sharks and rays use internal fertilisation.  INTERACTION: Have a sense organ called a lateral line. This runs along eachs side of the body and detects changes in water pressure or the presence of prey or predators.
   • CLASSIFYING FISH
     • CHONDRICHTHYES: such as rays and sharks have a flexible skeleton of cartilage. their skin is covered in denticles. OSTEICHTHYES: such as perch, cod and trout have a rigid bony skeleton. Most have smooth skin with thin transparent scales.