A World of Invertebrates скачать в хорошем качестве

A World of Invertebrates

Video of a Biology unit (age 12-14) Out of the five kingdoms for classifying living organisms, the animal kingdom contains by far the greatest number of known species. Traditionally, species were classified into two major groups: vertebrates and invertebrates. Vertebrates are animals with an internal spinal column: fish, amphibians, reptiles, birds, and mammals. In contrast, invertebrates are animals that do not have a spinal column. However, today this classification has become scientifically obsolete. Surely, you still remember that scientists have divided each kingdom of living organisms into large groups called phyla. Vertebrates represent only the vast majority of the phylum Chordata; invertebrates are grouped into approximately 40 different phyla! Indeed, more than 90% of existing animal species are invertebrates. And most of them belong only to 8 phyla: Porifera or sponges, the simplest of all invertebrates. Cnidarians, including corals and jellyfish. Platyhelminthes, flatworms with one opening in the digestive tube which serves as both mouth and anus. Nematodes, round, slender worms with a differentiated mouth and anus. Annelids, a different type of round worm with their body divided into segments. Mollusks, including a wide variety of animals such as mussels, snails, and octopuses. Echinoderms, including sea stars, the most prominent representative of this phylum. And arthropods, characterized by having joined appendages and an external skeleton. This phylum includes animals such as ants, beetles, crabs, spiders, scorpions, and millipedes. Of all eight phyla, arthropoda is by far the one with the greatest number of species. And within this phylum there’s a group that has the greatest number of species of all the animal kingdom. Welcome to a world almost fully dominated by...insects. Copyright © International Science Teaching Foundation & Science Bits, All rights reserved.