Transcript Eukaryotes

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Quick Review of Life
Three domains
Two are prokaryotes
 Archaea and Eubacteria
Third is Eukarya: organisms with
eukaryotic cell structure.
 Four kingdoms: Protista, Fungi, Plants
and Animals
 What’s an animal?

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An Animal IS:

Multicellular, heterotrophic organism that
develops from an embryo.
 Multicellular:
made up of more than 1 cell.
 Heterotrophic: uses pre-formed organic
compounds as source of nutrients, energy.
 Embryo: the earliest stage of a creature in
which the cells are undifferentiated, that is,
cells have not acquired specialized functions.
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Generally true of animals:

Reproduce sexually
 The
only cells that are haploid are gametes
(sperm and eggs). This ISN’T true of other
kingdoms. For example, moss is haploid.

Animals ingest their food.
 A few

parasitic ones absorb food, most ingest.
Most animals move
 Trying
to find food or mates
 Some only move parts
 Movement is coordinated: behavior.
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How are animals put together?
As multicellular organisms, animals are
highly structured
 Cells are differentiated (specialized)
 Cells with similar functions are organized
into tissues.
 Groups of tissues form organs, structures
that carry out certain functions for a body.
 Organs work together as organ systems.

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Do all animals have a complex structure?

The Parazoa have no organs
 Most
of the Parazoa are sponges.
 Sponges are aggregates of 3 types of cells
 You can mince up a sponge, and it will
reorganize to form a sponge again.
http://www.nationmaster.com/encyclopedia/Sponge; www.lausd.k12.ca.us/. ../sponge_bob.jpg
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Animals are all familiar?
There’s probably more than 4 million different
kinds of animals.
 Vertebrates (animals with backbones) are
1% of the total.
 Most different kinds of animals are insects,
snails, jellyfish, and worms, animals without
backbones.

http://212.84.179.117/i/Red%20Poplar%20Leaf%20Beetle.jpg
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As we go from simple animals to more
complex ones:

Symmetry
 Sponges
have none. They are blobs.
 Radial symmetry
 Bilateral symmetry

One way digestive tract
 Primitive
animals take food in, excrete, through
same opening.
 More advanced: a mouth at one end, an anus at
the other.
http://www.ndsu.nodak.edu/entomology/topics/images/bilat.jpg
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More advanced animals have a body cavity

A body cavity is called a coelom
 A place
where the internal organs go
Simple animals w/o a body cavity:
acoelomates
 Some simple animals
(roundworms = nematodes) have a
pseudocoelom

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
Mollusks, annelids and “beyond” have a
true coelom.
 Mollusks:
clams, snails, squid
 Annelids: earthworms
 Beyond: insects, vertebrates

Why is a coelom important?
 Allows
muscles and internal organs to
function without interfering with each other.
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Arthropods: the most successful
animals on earth.

Successful:
 more
different species than any other animal
 More individuals than any other animal
 1018 vs. 6 x109 humans

What do they have going for them?
 Exoskeleton
 Made
of protein and chitin; protection
 Jointed limbs
 Allows for agile movement
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How are arthropods classified?

Chelicerates
 Spiders,
mites, scorpions, horseshoe crabs
 Have specialized appendages used as fangs
NOTE
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
Crustaceans
 Lobsters,
crabs, shrimps, barnacles
 Have jaws and two pairs of antennae
www.microscopy-uk.org.uk/. ../seaart/cope.html ; www.fishingnj.org/ prolobs.htm
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
Uniramia: Insects, millipedes, and centipedes
 Insects:
6 legs, 3 segments (head, thorax, and
abdomen)
 Lots and lots of kinds and individuals
www.toptraders-egypt.com/ top-insects.html
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The most “advanced” animals

Deuterostomes
means 2nd, stome means mouth
 Other animals form mouth first, anus 2nd.
 Deuterostomes consist of 4 phyla:
 Echinoderms (spiny skin): starfish
 Arrow worms and acorn worms
 Chordata: From tunicates to tuna
 Deutero
http://www.seaforyourself.
com/images/Scrapbook/tu
nicate.jpg;
www.njscuba.net/biolog
y/ sw_fish_pelagic.html
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Chordates

Have a notochord
 A flexible
rod running down the back (dorsal)
 A dorsal hollow nerve cord
 Pharyngeal slits
 Gills in fish, other structures in humans
 A segmented body and postanal tail
 A tail that extends beyond the anus
http://www.petsmart.com/medi
a/ps/images/guides/aspca/Dog
/pointer_4dad.jpg
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Chordates range from simple looking to us

Tunicates are seasquirts
 Look
more like plants, even have cellulose
 During larval stage, have all the
characteristics of a chordate.
Lancelets are small fish-like animals
 3rd group is Vertebrates

 A variety
of fishes including sharks
 Amphibians, reptiles, birds, and mammals
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Life moves to land
Just like plants have adaptations allowing
life on land, so do animals
 Reptiles, birds, mammals have various
characteristics for life on land

 Skin
or scales that prevent drying
 Internal fertilization for reproduction
 Excretions that conserve water

We are mammals
 Females
have mammary glands to feed young
 We have hair; we have two sets of teeth.
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3 kinds of mammals

Marsupials
 Newborns
are undeveloped fetuses
 They complete growth in mother’s pouch

Placental mammals
 Development
takes place entirely in uterus of
the mother
 Placenta is structure within the uterus that
serves in nutrient and waste exchange

Monotremes
 Duckbilled
platypus; weird looking, lays eggs.
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http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/images/c01446.jpg
http://www.nature.com/news/2003/031110/images/breastfeeding_180.jpg
http://microscope.mbl.edu/baypaul/microscope/talks/biogeography/platypus.gif