Introduction to Animals

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Introduction to Animals

• Essential Questions
• What makes an animal an animal?
• How are animals classified?

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Kingdom Animalia

• Eukaryotic
• Heterotrophic
• Multicellular
• Tissues and organs formed by specialized cells
• No cell walls
• Likely evolved from animal-like protists

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Essential Functions

• All animals carry out the following
• Obtain food from the environment
• Exchange O2 CO2 through skin, gills, lungs, etc
• Move materials around body
• Get rid of wastes
• Process information with nerves
• All animals are motile at some point
• Most reproduce sexually, some asexually

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Reproduction Development

• Animals mainly reproduce sexually
• Fertilization sperm meets egg, either within or
  outside the body
• External fertilization (in water)
• Internal fertilization (on land)
• What are the positives
• and negatives of each
• type of fertilization?

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Reproduction Development

• Steps of Development
• Fertilization results in a unicellular zygote
• The unicellular zygote divides by mitosis
  cleavage
• A hollow ball of cells (blastula) forms
• Gastrulation (folding inward) forms 2 cells
  layers ectoderm and endoderm
• Mesoderm forms

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Coelomate vs Acoelomates

• Coelom fluid filled cavity that supports
  internal organs.
• Acoelomates no internal cavity. Example
  Flatworms
• Pseudocoelomates body cavity develops between
  endoderm and mesoderm. Example Roundworms
• Coelomates internal organs suspended in a body
  cavity surrounded by mesoderm. Example
  Earthworms

Why the Coelom? The coelom is significant because
as animals evolved, so did the presence of a
complex body cavity to support more complex
organs!
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Symmetry

• Animals can be described in terms of their
  symmetry
• Asymmetry irregular in shape Example Sponge
• Radial Symmetry can be divided through along
  any plane into halves from the mouth. Example
  Anemone
• Bilateral Symmetry can be divided lengthwise
  into 2 mirror images. Example Humans
• Cephalization concentration of sense organs at
  the front (top) of the body

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Body Positioning

• Bisymmetrical animals have 4 parts
• Anterior the head end, where sensory organs are
  located
• Posterior the tail end (anus)
• Dorsal Back surface where the spine is located
• Ventral The belly side

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Framework for support Skeletons

• Exoskeletons hard, waxy covering on the
  exterior of the body.
• Prevent water loss, protect soft tissues
• Endoskeletons internal skeleton for support
  made of Calcium Carbonate, cartilage or bone
• Protects internal organs and an internal brace
  for muscles to pull against

To survive on land, why is it important to have a
strong skeleton?
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Framework for support Skeletons

• Invertebrates an animal without a backbone
  usually has exoskeleton
• Echinoderms have endoskeletons
• Vertebrates an animal with a backbone
  bilaterally symmetry exoskeleton

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Invertebrates

• Make up 95 of all animals
• No backbone, or vertebral column. Most have
  exoskeletons.
• Open circulatory systems (with a one chambered
  heart)
• Cannot process Oxygen very well, restricts their
  size and survival on land.

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Invertebrate Phyla

• Phylum Porifera - Sponges
• Phylum Cnidaria Corals, Hydra Jellyfish
• Phylum Platyhelminthes - Flatworms
• Phylum Nematoda Roundworms
• Phylum Mollusca Snails, squid Clams
• Phylum Annelida - Segmented Worms
• Phylum Arthropoda Insects, spiders, lobsters
• Phylum Enchinodermata Starfish
• Invertebrate members of Phylum Chordata Sea
  squirts, Lancelets

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Phylum Annelida

• The segmented worms. Example earthworms,
  leeches
• Segmentation allows movement of individual parts
• Possess a true coelom
• Specialized organs and systems

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Phylum Chordata Subphylum Vertebrata

• Class Agnatha (jawless fishes)
• Class Chondrichthyes (cartilaginous fishes)
• Class Osteichthyes (bony fishes)
• Class Amphibia (amphibians)
• Class Reptilia (reptiles)
• Class Aves (birds)
• Class Mammalia (mammals)

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Vertebrates

• 5 of all animals
• Have a vertebral column.
• The backbone gives support to the body and
  protection to the spinal cord
• Have endoskeletons.
• Closed circulatory system with a multichambered
  heart
• Classification Kingdom Animalia, Phylum
  Chordata, Subphylum - Vertebrata

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Types of Mammals

• Subclasses based on type of reproduction
• Placental (95) young fully develops in uterus
  before birth
• Marsupials short period of development inside
  the mother followed by a second period of
  development inside pouch
• Monotremes - lay eggs. species platypus and 2
  echidnas

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Vertebrates Am I hot or not?

• The major difference between vertebrates is
  whether or not they can regulate their own body
  temperature.
• Ectotherms regulated by environment
• Example fish, frogs, snakes
• Endotherms regulated by their own body
• Example mammals

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• Animals that are ectothermic (like snakes) dont
  require food as much as endotherms.
• What does this indicate about the
  relationship between food requirements and the
  generation of body heat?
• How does this fact restrict where certain
  types of animals can live?
• If the environment were to suddenly get cold
  (like an ice age), which of the animals could
  survive?