Introduction to Animals

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Introduction to Animals
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• Over a million different types have been
  identified!
• Animals likely evolved from protozoans.
• Kingdom Protista

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Section 1

• blastula (596)
• ectoderm (596)
• endoderm (596)
• mesoderm (596)
• body plan (598)
• asymmetrical (598)
• radial symmetry (598)
• bilateral symmetry (598)
• cephalization (599)
• coelom (600)
• acoelomate (600)
• pseudocoelomate (600)
• coelomate (600)
• phylogenetic tree (602)

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Characteristics of Animals

• All animals share these general features
• heterotrophy,
• mobility,
• multicellularity,
• sexual reproduction,
• diploidy,
• the absence of a cell wall,
• cells organized as tissues, and
• blastula formation.

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heterotrophy,

• Cant make their own food must eat things.

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mobility,

• Animals can swim, crawl, walk, run, and even fly.
• Some only move in the larval stage the sponge

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multicellularity,

• Made up of more then one cell!
• Although animals come in a wide range of sizes,
  the cell sizes are all very similar!

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sexual reproduction

• Almost all animals reproduce sexually by
  producing gametes.
• Unlike the egg cells, the sperm cells of animals
  have a flagella and are highly mobile.

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diploidy,

• adults have two copies of each chromosome, one
  inherited from their father and one from their
  mother.

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the absence of a cell wall,

• Among the cells of multicellular organisms, only
  animal cells lack rigid cell walls. The absence
  of a cell wall has allowed animals mobility that
  other multicellular organisms do not have.

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blastula formation

• In all animals except sponges, the zygote
  (fertilized egg cell) undergoes cell divisions
  that form a hollow ball of cells called a
  blastula.

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cells organized as tissues
Cells within the blastula eventually develop into
three distinct layers of cells endoderm,
ectoderm, and mesoderm . These layers are called
the primary tissue layers because they give rise
to all of the tissues and organs of the adult
body.
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tissues

• tissues are groups of cells with a common
  structure that work together to perform a
  specific function.

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Body Symmetry

• All animals have their own particular body plan,
  a term used to describe an animals shape,
  symmetry, and internal organization.

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3 body symmetry
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Asymmetry.

• Animals that grow in an irregular pattern, such
  as a sponge, show asymmetry.

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radial symmetry

• Animals with radial symmetry have body parts
  arranged
• around a central axis.

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bilateral symmetry

• Animals with bilateral symmetry have
• a distinct right and left half, and most display
  cephalization.

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body plans

• Animals have one of three basic body plans
  acoelomate, pseudocoelomate, and coelomate.

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coelom

• a body cavity, coelom or (SEE luhm), a
  fluid-filled space found between the body wall
  and the digestive tract (gut).
• This space is lined with cells that come from
  mesoderm.

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• Coelomates are either protostomes or
  deuterostomes.
• Protostomes (first mouth) are coelomates whose
  embryonic development shows a blastopore
  associated with a mouth.
• Deuterostomes (second mouth) are coelomates whose
  embryonic development shows a blastopore
  associated with an anus, with a second opening
  forming the mouth (hence "second mouth").

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acoelomate

• Animals with no body cavity are called acoelomate
  (ay SEEL oh mayts).
• The space between an acoelomates body wall and
  gut is completely filled with tissues

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pseudocoelomate

• have a body cavity located between the mesoderm
  and endoderm. Their body cavity is called a
  pseudocoelom (false coelom)

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Body plans
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Segmentation

• Segmentation in body structure underlies the
  organization of all advanced animals.

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• Some animals have their bodies divided into
  segments. This allows them to specialize certain
  segments, such as for antennae, eyes, claws, etc.
  Humans, insects, and earthworms are examples of
  segmented animals.

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animal phyla

• There are about 35 animal phyla, which contain an
  extraordinary range of body forms and body
  systems.
• .

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phylogenetic tree

• To visually represent the relationships among
  various groups of animals, scientists often use a
  type of branching diagram called a phylogenetic
  tree.
• It shows how animals are related through evolution

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• Scientists classify animals using several
  different types of data, which include comparing
  anatomy and physiology, patterns of development,
  and DNA.

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• The animal kingdom is divided in two groups
  vertebrates and invertebrates

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Section 2

• gastrovascular cavity (605)
• respiration (605)
• gill (605)
• open circulatory system (606)
• closed circulatory system (606)
• hydrostatic skeleton (607)
• exoskeleton (607)
• endoskeleton (608)
• hermaphrodite (609)
• external fertilization (610)
• internal fertilization (610)

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Animal Body Systems

• Body systems are specialized to carry out
  different tasks.
• Levels of organization
• Cells tissues organs organ
  systems
• organisms

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Digestive systems

• Simple animals have a gastrovascular cavity with
  only one opening, while more-complex animals have
  a one-way gut.

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Respiration/ gas exchange

• Simple animals exchange gases directly through
  their skin.
• More-complex aquatic animals use gills, while
  terrestrial animals use a variety of respiratory
  organs, such as lungs.

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circulatory system

• In an open circulatory system, circulatory fluid
  leaves the vessels and enters the body cavity.
• In a closed circulatory system, blood remains in
  the vessels.

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open circulatory system -- primitive system found
in insects and crustaceans -- blood not always
contained in blood vessels -- heart pumps
hemolymph (blood and cell fluids) into vessels,
but vessels empty into large cavities or sinuses
containing organs -- blood diffuses through
tissues and back into heart.
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closed circulatory system -- found in higher
animals -- system is "closed" because the blood
is always contained in vessels.
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Nervous System

• While simple animals have little coordination
  among their nerve cells, complex animals have
  nerve cords and a brain with associated sensory
  structures.

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Excretory System

• For most animals, eliminating wastes is linked to
  maintaining the correct water balance in their
  body.

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Skeleton/Support
Hydrostatic support Exoskeleton Endoskeleton
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Frog
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Asexual

• Asexual reproductive methods include
  fragmentation, splitting in two, and
  parthenogenesis.

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• Reproduction that does not involve the fusion of
  two gametes is called asexual reproduction. A
  sponge, for example, can reproduce by fragmenting
  its body. Each fragment grows into a new sponge.
• Some species of sea anemone reproduce by pulling
  themselves in half, forming two new adult anemones

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sexual reproduction

• In sexual reproduction, male and female gametes
  combine to form a new individual

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Human Reproduction

• Eggs produced in the ovary are fertilized in the
  fallopian tube and implant in the uterus. Sperm,
  made in the testes by spermatogenesis, a form of
  meiosis, must fertilize the haploid egg for it to
  develop into an embryo.