Download Coelomate

Extant
How Many Kingdoms?
8
5
3
Extinct
2
1
Original Cell
Animal Features
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Multicellular Eukaryotes
Heterotrophic Ingestion
Collagen Protein Connections
Nerve and Muscle Tissues
Diplontic (Gametic) Life History
Gametes Oogamous with Flagellated Sperm
Zygote to Blastula, perhaps Gastrulation
Larval metamorphosis into Adult
Ontogeny Recapitulating Phylogeny
Animals
Domain Eukarya
Kingdom Animalia
Phylum Nematoda
http://creatures.ifas.ufl.edu/nematode/nem_fig1.jpg
Nematode Body Organization
http://www.ua.es/dpto/dcarn/fitopatologia/Images/Celegans1.jpg
http://www.ucmp.berkeley.edu/phyla/ecdysozoa/nematodexssm.gif
days at 20°C
vulva
anus
mouth
http://www.esa.int/export/images/Ce_400.jpg
embryo in
shell of
zygote
http://www.apsnet.org/education/feature/Celegans/Images/fig5.JPG
http://ucdnema.ucdavis.edu/imagemap/nemmap/Ent156html/nemas/c-elegans.gif
Caenorhabditis elegans is a bacteriovorous soil nematode, feeds on
E. coli in vitro, is a genetic model organism, its
genome is sequenced.
N=6
protandrous
XX=hermaphrodite
XO=male
Life cycle: 3
meiosis
syngamy
protandrous
http://nema.cap.ed.ac.uk/Caenorhabditis/C_elegans_genome/celeganslifecycle.jpg
Animals
Domain Eukarya
Kingdom Animalia
Phylum Annelida
Lumbriculus variegatus : California mudworm
This is an aquatic oligochaete annelid
Mouth feeds in sediments
Tail extends toward water surface for gas exchange
Body walls nearly transparent for easy observation
For example: may count pulses of blood in dorsal vessel
http://www.westminster.net/faculty/cobler/Lumbriculus%20variegatus.jpg
Lumbricus terrestris: Canadian nightcrawler or Earthworm
clitellum
mouth
anus
http://iris.cnice.mecd.es/biosfera/alumno/1bachillerato/animal/imagenes/nervio/lumbricus.jpg
edge of ventral reproductive structures
The earthworm
body is
fundamentally
segmented. Here is
a typical segment:
Each segment is
filled with coelomic
fluid, under some
pressure, which
provides “stiffness.”
The segments near
the head are
specialized for other
physiological
functions.
http://www.mun.ca/biology/scarr/142003_Annelida.jpg
Major Organ Systems in an Earthworm
Excretory:
Reproductive: Circulatory:
Male
Gases,
Digestive:
Female
Nutrients, Food Intake
Wastes
Nutrient
Absorption Muscular:
Movement
Dermal:
Gas
Exchange
Nervous: Sensory
and Coordination
http://www.esu.edu/~milewski/intro_biol_two/lab__12_annel_arthro/images/lumbr_diagr_dissection.jpg
http://myhome.naver.com/c65hoi5/c3/c33236.jpg
http://www.student.loretto.org/zoology/phylum_annelida.htm
Characteristics
• More than 100 segments
• Segments separated by partitions that divide coelom
• Segments identical except when specialized and fused
• Anterior and posterior ends
• Cephalization specialized for burrowing
• Head contains sense organs
• Circular and longitudinal muscles
1
2
3
4
5
6
7
8
9
10
11
12
13
Mouth
Prostomium
Segment
Spermathecal openings
Female (oviduct) opening
Male (vas deferens) opening
Sperm groove
Papilla
Clitellum (saddle)
Paired setae (ventro-lateral)
Anus
Dorsal surface
Ventral surface
http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20external%20form.htm
http://www.student.loretto.org/zoology/phylum_annelida.htm
Movement
• Setae anchored during movement
• Circular muscles contract
• Hydrostatic pressure increases in anterior coelomic cavities
• Body elongates pushing head forward
• Anterior setae grip ground
• Longitudinal muscles contract--posterior pulled along
• Coelomic divisions allow simultaneous contraction and expansion of segments
A
B
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
External view
Section through segment
Coelom
Circular muscle
Cuticle
Intestine
Dorsal blood vessel
Typhlosole
Epidermis
Nephridium
Longitudinal muscle
Seta
Protractor muscle
Retractor muscle
Ventral nerve cord
Subneural vessel
Ventral vessel
Septum
http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20muscle%20system.htm
http://www.student.loretto.org/zoology/phylum_annelida.htm
Nervous
• Sensitive to tough, light, moisture, chemicals, temperature, and vibrations
• Light receptors on head and tail--sense direction
• Most sense organs and nerves control muscle contractions in individual segments
• Pair of ganglia in each segment coordinate movement with adjacent segments
• Cerebral ganglion in head controls total body
• Ventral nerve cord connects brain with ganglia
1
2
3
4
5
6
7
8
9
10
11
12
13
Anus
Intestine
Cerebral ganglion
Prostomium
Mouth
Nerve collar
Segmental ganglion
Pharynx
Esophagus
Segmental nerve
Crop
Gizzard
Ventral nerve cord
http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20digestive%20and%20nervous%20systems.htm
http://www.student.loretto.org/zoology/phylum_annelida.htm
Feeding
• Feed on organic matter in soil
• Digest organic matter
• Wastes and undigested soil eliminated as casting
• Loosens and aerates soil
Digestion
• Soil sucked in by pharynx -> esophagus -> crop (storage) ->
• gizzard (grinds soil releasing organic matter) ->
• intestine (nutrients absorbed)
1
2
3
4
5
6
7
8
9
10
11
12
13
Anus
Intestine
Cerebral ganglion
Prostomium
Mouth
Nerve collar
Segmental ganglion
Pharynx
Esophagus
Segmental nerve
Crop
Gizzard
Ventral nerve cord
http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20digestive%20and%20nervous%20systems.htm
http://www.student.loretto.org/zoology/phylum_annelida.htm
Circulation
• Transport oxygen, nutrients, and wastes
• Flow of blood toward posterior via ventral blood vessel
• Flow of blood toward anterior via dorsal blood vessel
• 5 pair of aortic arches link vessels near anterior
• Smaller vessels branch into segments
• Contraction of ventral vessel and aortic arches forces blood through body
1
2
3
4
5
6
7
8
Anus
Dorso-subneural vessel
Intestine
Dorsal vessel
Hearts (aortic arches)
Mouth
Ventral vessel
Subneural vessel
http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20circulatory%20system.htm
http://www.student.loretto.org/zoology/phylum_annelida.htm
Gas Exchange
• Lack gills or lungs--oxygen and carbon dioxide diffuse across skin
• Requires moist skin, thin cuticle, mucus secretion…limits habitat!
Excretion
• Elimination of nitrogen wastes
• Long tubules (nephridia) excrete wastes
• Coelomic fluid enters nephridium through ciliated funnel opening
• Some water reabsorbed by blood
• Remaining fluid excreted through ventral pores
A External view
B Excretory system (nephridium)
C-D Reproductive system
C Lateral view
D Dorsal view
1 Nephrostome
2 Septum
3 Ciliated tube
4 Bladder
5 Nephridiopore
6 Body wall
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20excretory%20and%20reproductive%20systems.htm
http://www.student.loretto.org/zoology/phylum_annelida.htm
Reproduction
• Hermaphrodites--cannot self fertilize
• Worms join head to tail
• Form mucus coat around bodies--each inject sperm into mucus
• Sperm move to seminal receptacle
• Eggs move through oviducts to female genital pore
• Clitellum secretes mucus and chitinous sheath
• Worm wiggles to slip off sheath
• Eggs and sperm join
A External view
B Excretory system (nephridium)
C-D Reproductive system
C Lateral view
D Dorsal view
1 Nephrostome
2 Septum
3 Ciliated tube
4 Bladder
5 Nephridiopore
6 Body wall
7 Seminal vesicle
8 Testis
9 Egg sac
10 Male opening
11 Female opening
12 Oviduct
13 Ovary
14 Sperm duct (vas deferens)
15 Opening to sperm-receiving sac
16 Sperm-receiving sac (spermatheca)
http://www.student.loretto.org/zoology/Graphic%20webs/Earthworm-%20excretory%20and%20reproductive%20systems.htm
http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/animals/worm_stuff/worm_ventral.html
http://sps.k12.ar.us/massengale/images/worms_mating.jpg
http://sps.k12.ar.us/massengale/earthworm_dissection.htm
Animals probably evolved from a flagellated protist
similar to the choanoflagellates
flagellum
One step in this evolution
is to become colonial.
collar
Here are the choanocytes
cell body
of one of the simplest of
sponges. Basically the
most primitive animals.
http://192.171.163.165/pil/Choanoflagellate_spp..jpg
Of course the other
required step is to
eliminate the chloroplasts
of the choanoflagellate
(Chrysophyta!).
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
http://ebiomedia.com/downloads/sponges.pdf
Evolution of Body Organization
Sponge, Cnidarian
spongocoel
Planarian
Ectoderm
Endoderm
Mesoderm
2-layered
3-layered
Acoelomate
gastrovascular
cavity
Nematode
pseudocoelom
digestive
tract
Annelid
Pseudocoelomate
Coelomate
coelom
Development or Evolution?
zygote
cleavage
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
blastula
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
2-layered
acoelomate
body plan
Origin of Mesoderm
Cnidarians
blastocoel
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TIFF (LZW) decompressor
are needed to see this picture.
Platyhelminthes
Nematoda
Annelida
Mollusca
Arthropoda
Protostome Phyla
archenteron
Echinodermata
Hemichordata
Chordata
Deuterostome Phyla
(except vertebrates)
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
blastopore
mouth
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
mouth
anus
The Animal Clade
Extant
deuterostomia
protostomia
acoelomates
radiata
pseudocoelomates
bilateria
parazoa
eumetazoa (true tissues)
loss of chloroplast, colonial organization
Ancestral Choanoflagellate
coelomates
This cladogram omits
several smaller animal
phyla!