Overview of Animal Diversity

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Overview of Animal Diversity
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31.1 Animals are multicellular heterotrophs
without cell walls.Some General Features of
Animals Animals are multicellular
heterotrophs that are diverse in form and
habitat, are mobile, reproduce sexually, and have
characteristic embryonic development. (p. 618)
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31.2 Animals are a very diverse kingdom.The
Traditional Classification of Animals
Taxonomists have traditionally created
phylogenies by comparing anatomical features and
embryological development. (p. 620)
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Kingdom Animalia is traditionally divided into
the Parazoa lack a definite symmetry and
organized tissues. Eumetazoa have a definite
symmetry and organized tissues. (p. 620)
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The eumetazoan branch is divided into Radiata
and Bilateria -having bilateral symmetry.
(p. 620) Bilateral animals further split into
groups with and without a body cavity (coelom).
(p. 620)This is a distinction long used for
classification
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Types of Body Cavitiespg 625

• Acoelomate -no body cavity
• flatworms
• Pseudocoelomate-pseudocoel located between
  mesoderm and endoderm
• roundworms, rotifers
• Coelomate- body cavity completely contained
  within mesoderm
• many members inc Homo sapiens

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Protostome/ Deuterostome

• Protostome-
• Spiral Cleavage
• Determinate Devo
• Blastopore (invagination of blatula) becomes
  mouth
• Deuterostome
• Radial Cleavage
• Indeterminate Devo (stem cells)
• Blastopore becomes anus

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Segmentation

• Each segment may have full set of organs
• Life may continue if a segment is injured
• Facilitates more complex locomotion

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• 32.3 Acoelomates are solid worms that lack a body
  cavity.
• Flatworms (platyhelminthes), simple body
  structure with ability to regenerate lost parts-
  (page 642)

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• 32.4 Pseudocoelomates have a simple body
  cavity.The Pseudocoelomates In the
  pseudocoelomates, circulation occurs in a
  pseudocoel, not in a defined circulatory system.
  (p. 646)
• Nematodes-ex parasitic Trichenella (raw pork)
  (page 647)

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• Puzzles related to Animal Evolution
• "Evo-Devo" and the Roots of the Animal Family
  Tree
• Origin of sponges?
• The multinucleate hypothesis, the colonial
  flagellate hypothesis, and the polyphyletic
  origin hypothesis all try to account for the
  origin of metazoans from single-celled protists.
  (p. 630)

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• Puzzles related to Animal Evolution
• A large diversity of animal body plans occurred
  around the Cambrian period, with no new
  innovations since. (p. 630) Cause?...
• the emergence of predatory lifestyles or
  geological factors.
• debut of Hox genes within developing animal
  embryos. (p. 630)

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INVERTEBRATES
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• 33.1 Mollusks were among the first
  coelomates.Mollusk Body Plan The evolution of
  a coelom was a significant advance in animal body
  structure because it repositions fluid and allows
  complex tissues and organs to develop. (p.
  652)

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• The molluscan body plan is bilaterally
  symmetrical, with an efficient excretory system
  and a muscular foot for locomotion. (p. 653-4)
  Many have rasping (scraping) tongue called
  radula.

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• Major Classes of Mollusks Major classes of
  mollusks include the class Gastropoda (snails and
  slugs), class Bivalvia (bivalves), and class
  Cephalopoda (octopuses, squids, and nautiluses).
  (pp. 656-657)

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33.2 Annelids were the first segmented
animals.Segmented Bodies

• Segmentation was a key transition in animal
  body plans, because similar segments can be
  individually controlled for different functions.
  (p. 658) Three principal features of annelids
  are repeated segments, specialized segments, and
  connections between segments. (p. 658)

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• Tube within a tube body plan. (p. 658)
  Locomotion --hydrostatic skeleton forces fluid
  from one segment to the next. (p. 658) Major
  Classes of Annelids 12,000 species , three
  classes
• Polychaeta (polychaetes), Oligochaeta
  (earthworms), and Hirudinea (leeches). (pp.
  660-661)

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33.3 Lophophorates appear to be a transitional
group. Lophophorates

• The marine phyla Phoronida (phoronids),
  Ectoprocta (bryozoans), and Brachiopoda
  (brachiopods) are characterized by a ridge around
  the mouth bearing ciliated, hollow tentacles
  (lophophore) that functions in gas exchange and
  food collection. (pp. 662-663)

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33.4 Arthropods are the most diverse of all
animal groups.Arthropod Body Plan

• Over two-thirds of all named species on the earth
  are arthropods. (p. 664)

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arthropod body plan

• Jointed appendages --
• legs, antennae, and mouthparts, and an
• exoskeleton of chitin and protein used for
  protection and water loss prevention,
• most diverse phylum on the planet. (p. 664)
• Arthropods are segmented, with some segments
  fused into functional groups (ex head, thorax)
  (pp. 665-666)

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arthropods

• The exoskeleton is secreted by, and fused
  with, the epidermis, and provides a hard surface
  for muscle attachment. (p. 666) All arthropods
  have an open circulatory system some have
  adaptations such as compound eyes, a respiratory
  system composed of tracheae, and an excretory
  system composed of Malpighian tubules. (pp.
  666-667)

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• Why must arthropods molt?

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A Major Group of Arthropods Crustaceans

• Most crustaceans (35,000 species) have two pairs
  of antennae, three types of chewing appendages,
  and various pairs of legs. (p. 668)
  Crustaceans are found in marine, freshwater, and
  terrestrial habitats. (pp. 668-669)

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Major Classes of Arthropods Arachnids

• Arachnids (57,000 species) have a pair of
  chelicerae, a pair of pedipalps, and four pairs
  of walking legs. (p. 670)
• Two major orders are Araneae (spiders) and Acari
  (mites and ticks). (p. 670)

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Major Classes of Arthropods Centipedes and
Millipedes

• Centipedes (class Chilopoda) and millipedes
  (class Diplopoda) are made of a head region
  followed by numerous similar segments.
• Centipedes have one pair of legs per segment, and
  millipedes have two pairs per segment.
• (p. 671)

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Major Classes of Arthropods Insects

• Class Insecta is the largest group of organisms
  on the planet, living in nearly every possible
  habitat. (p. 672) Most are relatively small,
  and contain three body sections head, thorax,
  and abdomen, with three pairs of legs attached to
  the thorax, and one pair of antennae. (p. 674)
  Most insects have compound eyes. (p. 674)

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insects

• Sensory hairs, tympanal organs (sense vibrations
  such as sound waves) and chemoreceptors all act
  as sense receptors in insects. (p. 675) Many
  insects undergo either simple or complex
  metamorphosis. (p. 675)
• What are the stages of complete metamorphosis?

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Echinoderms

• 33.5 Echinoderms are radially symmetrical as
  adults.Deuterostome Development and an
  Endoskeleton Echinoderms are marine animals
  with hard calcium plates forming a true
  endoskeleton in young individuals. (p. 676)

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Echinoderm Body Plan

• All echinoderms are bilaterally symmetrical
  during larval development, and become radially
  symmetrical as adults. (p. 678) Echinoderms
  have a five-part body plan with a central,
  branched nerve ring and an endoskeleton composed
  of calcium-rich plates (ossicles). (p. 678)
  Many echinoderms can regenerate lost parts, but
  in most of them, reproduction is sexual and
  external. (p. 679)

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• Echinoderms have a water vascular system
• Water pressure fills tube feet which allows
  movement and feeding. They have enough strength
  to pull apart a clam shell, which I cannot do.
  Then they stick their stomach inside and start
  digesting.

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• Major Classes of Echinoderms There are six
  living classes of Echinoderms Crinoidea (sea
  lilies and feather stars), Asteroidea (sea stars
  or starfish), Ophiuroidea (brittle stars),
  Echinoidea (sea urchins and sand dollars),
  Holothuroidea (sea cucumbers), and
  Concentricycloidea (sea daisies). (p. 680)

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VERTEBRATES
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• 34.1 Attaching muscles to an internal framework
  greatly improves movement.The Chordates Four
  features characterize the chordates (1) single,
  hollow nerve cord (2) a flexible notochord
  present at some developmental stage (3)
  pharyngeal pouches connecting the pharynx and the
  esophagus (gill slits in human embryos) (4) a
  postanal tail at least during embryonic
  development. (p. 684)

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• 34.2 Nonvertebrate chordates have a notochord but
  no backbone.The Nonvertebrate Chordates
  Tunicates possess a notochord and a nerve cord as
  larvae, but look at them as adults! (p. 686)
  Lancelets are fishlike marine chordates with a
  permanent notochord running the entire length of
  the dorsal nerve cord. (p. 687)

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• 34.3 The evolution of vertebrates involved
  invasions of sea, land, and air.Characteristics
  of Vertebrates Vertebrates -vertebral column
  instead of a notochord and a distinct head. (p.
  688) The history of the vertebrates -they
  invaded the sea and then the land. (p. 689)

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Vertebrates are distinguished from other chordates

• Neural crest (page 688 and 1090-91)
• Internal organs
• Endoskeleton of bone or cartilage for size and
  movement

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• Fishes Fish were the first vertebrates and are
  the most diverse and successful vertebrate group.
  (p. 690) Key characteristics of fish include a
  vertebral column, jaws and paired appendages,
  gills, single-loop circulation, and nutritional
  deficiencies (which means they need to eat
  nitrogen). (p. 690)

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• Sharks eventually became dominant sea predators,
  partially due to a skeleton composed of calcified
  cartilage. Sharks were also among the first
  vertebrates to develop teeth. (p. 695)
• What do you know about sharks teeth?

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• Bony fish -- ossification provided a strong base
  for muscle attachment and evolved in fresh water.
  (p. 696)
• swim bladder for buoyancy,
• a lateral line sensory system,
• and a gill cover (operculum) to permit water to
  be pumped over the gills. (pp. 696-697)

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• Amphibians legs
• cutaneous respiration
• lungs, pulmonary veins
• partially divided heart. (p. 698)
• evolved from lobe-finned fishes.
• Include frogs and toads, salamanders, and
  caecilians. (pp. 699-701)

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• Reptiles Key characteristics of reptiles
  include the amniotic egg, dry skin, and thoracic
  breathing (expand ribcage). (p. 702)
• Turtles, lizards and snakes, tuataras, and
  crocodiles. (pp. 707-709)

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• Birds Modern birds retain many reptilian
  characteristics, but lack teeth and have
  vestigial tails. They are distinguished from
  living reptiles by feathers and the presence of a
  thin, hollow flight skeleton. (p. 710)
• Descended from dinosaurs

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• Mammals Hair, mammary glands, a placenta,
  heterodont dentition, the ability to digest plant
  material, keratinized hooves and horns, and
  flight capability (in bats). (pp. 714-716)

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• The Orders of Mammals Mammals were not common
  until dinosaurs disappeared. Modern mammals fall
  into one of three categories monotremes,
  egg-laying mammals marsupials, pouched mammals
  and placentals. (pp. 717-718)

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• 34.4 Evolution among the primates has focused on
  brain size and locomotion.Primates Grasping
  fingers and toes and binocular vision are two
  features that allowed primates to flourish. (p.
  720) Modern prosimians include lemurs,
  lorises, and tarsiers, while anthropoids include
  monkeys, apes, and humans. (pp. 720-721)
  -Zaboomafoo from PBS

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• Australopithecines Bipedalism marked the
  beginning of hominid evolution, although the
  reason for such evolution remains controversial.
  (p. 722)
• What are some possible reasons?
• Maybe its just so we can hold hands.

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• The Genus Homo The first humans (Homo habilis)
  evolved from australopithecine ancestors about 2
  MYA. (p. 724) Homo erectus replaced H.
  habilis, and is believed to have come out of
  Africa. (pp. 724-725)

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• Homo sapiens is both the only surviving species
  of the genus Homo and the only surviving hominid.
  (p. 726) Humans are the only animals that can
  effectively make tools, that have refined and
  extended the ability to use conceptual thought,
  and that can use symbolic language and shape
  concepts and experiences with words. (p. 726)
  but, Think Tank in National Zoo...

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Taung Skull2.5 myo Australopithicus afarensis
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Taung Skull Site
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Human Evolved from Monkey?

• If humans did evolve from monkeys (or gorillas)
  or anything from this chart, how would this
  change the phylogenic tree?