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Introduction to Animals

Introduction to Animals

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Introduction to Animals

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  1. Introduction to Animals Chapter 32

  2. Characteristics of ALL Animals • Eukaryotic, multicellular, heterotrophic • Can be invertebrates of vertebrates • 95% of animals are invertebrates • ALL animals are multicellular so their cells must have a degree of specialization • Cells -> Tissues -> Organs -> Organ Systems -> Organisms

  3. http://www.youtube.com/watch?v=bYXXGFf7c9Q

  4. Classification of Animals • The first animals were aquatic, but a lot of animals have evolved to be terrestrial • Early taxonomists used fossils, body symmetry, and development to classify animals • Now, we can use DNA and RNA to better understand relationships

  5. Body Structure • Animals have patterns to their body structure: • Asymmetrical (no symmetry) • Radial symmetry (circular) • Bilateral symmetry (two halves) • Most animals will be radially or bilaterally symmetrical • Animals with bilateral symmetry tend to have sensory and brain structures (HUMANS)

  6. Invertebrates • DO NOT HAVE A BACKBONE • Can exhibit all types of symmetry • Invertebrates range from very simple to very complex organisms • Some inverts are segmented (earth worms) into similar repeating units on their bodies • All inverts are different in their body support, respiratory/circulatory systems, digestive/excretory systems, nervous system and reproduction

  7. Vertebrates • HAVE A BACKBONE! • Includes fishes, amphibians, reptiles, birds and mammals • All vertebrates have an endoskeleton which supports their muscles, tissues and organs • There are many differences between aquatic and terrestrial vertebrates: respiratory/circulatory systems, nervous system and reproduction

  8. Fertilization • Some inverts have the ability to use asexual reproduction, but most animals use sexual reproduction • Animals must produce gametes (sperm and egg), which come together to form a zygote • During fertilization, the sperm cell membrane fuses with the egg cell membrane • After fusion, the sperm DNA enters the nucleus of the egg and their DNA join

  9. Development • After fertilization, the new embryo goes through several stages of mitosis • The new ball of cells (the blastula), will then start to form body cavities and organs • Animals have different patterns of development, but the common thread is differentiation • Differentiation is the change of a cell from a stem cell to an organ

  10. Videos • Fertilization: • http://www.youtube.com/watch?v=gtPd4Yn_18c • Development: • http://www.youtube.com/watch?v=fXeN_rMJIu0