Download Animal body plans

Animal body plans I
Animal body plans
• A body plan is a set of fundamental traits - a basic
structural blueprint - shared among a vast number of
related organisms.
• There is a limited range of body plans among all living
animals (between 30 and 35)
• Morphological differences between body plans are
known as disparity (compare to diversity)
Crown groups and stem groups
http://burgess-shale.rom.on.ca/en/science/origin/01-life-tree.php
Lines of Evidence
• Fossil record
• Comparative
morphology
• Comparative
genomics
•
“Evo-Devo”
•
Hox genes
Evolution of Animals
Multicellularity and origins
Digestive
cavity
Reproductive
cells
1
Early colony
of protists;
aggregate of
identical cells
Somatic
cells
3
2
Hollow sphere
(shown in
cross section)
4
Beginning
of cell
specialization
(cross section)
5
Infolding
(cross section)
Gastrula-like
“protoanimal”
(cross section)
What is an animal?
•
•
•
•
Multicellular
Motility
Aerobic respiration
Heterotrophs
•
Ingest food before
digesting
• Neurons (except
sponges)
• Muscle cells (except
sponges)
7
HAPLOID
What is an Animal?
Eggs
1
• Most are diploid
except for haploid
eggs and sperm
• Animals proceed
through a welldefined life cycle
•
includes embryonic
development
2
Adult
7
Digestive
tract
6
Zygote
(fertilized egg)
DIPLOID
Larva
Outer cell layer
(ectoderm)
Inner cell layer
(endoderm)
Opening
5
Later gastrula
(cross section)
Sperm
3
Blastula
(cross section)
4
Early gastrula
(cross section)
8
Choanoflagellates
Fungi
Porifera
(Sponges)
Animalia
multicellularity
Ctenophora
Major animal
phyla
Cnidaria
Acoels
diploblasty
LOPHOTROCHOZOAN
Rotifera
Loss of coelom
Platyhelminthes
Segmentation
triploblasty
Annelida
Protostome development
Mollusca
PROTOSTOMES
BILATERA
ECDYSOZOA
Nematoda
Cephalization, CNS, coelom
Segmentation
Arthropoda
DEUTEROSTOMES
Echinodermata
Radial symmetry (adults)
Deuterostome development
Freeman 2014
Chordata
Segmentation
DEUTEROSTOMES
Evolutionary innovations in animals
•
•
•
•
•
•
Type of symmetry
Number of openings
Tissue complexity and organization
Type of coelom
Segmentation
Type of developmental pathways
10
Symmetry
Bilateral symmetry
11
Number of openings
12
Tissue complexity
•
Diploblastic versus triploblastic
Tissue complexity
• Embryonic cells give rise to primary tissue layers
•
•
•
ectoderm
endoderm
mesoderm
Body covering
(from ectoderm)
Tissuefilled region
(from mesoderm)
Digestive tract
(from endoderm)
14
Type of coelom: Acoelomate Animals
• Simplest Organ systems
epidermis
gut cavity
no body cavity; region
between gut and body wall
packed with organs
15
Development of a coelom
Ectoderm
Mesoderm
Endoderm
16
Type of coelom: Pseudocoelomate animals
• A “false coelom”, body cavity without a peritoneum
epidermis
gut cavity
unlined body
cavity (pseudocoel)
around gut
17
Type of coelom: Coelomate animals
• A true coelom – the body cavity has a unique tissue
lining called a peritoneum
Ectoderm
Mesentery
Peritoneum
Endoderm
Coelom
Mesoderm
18
The peritoneum encloses organs
• ……. and holds these organs in place.
gut cavity
epidermis
peritoneum
lined body cavity (coelom); lining also holds internal
organs in place
19
Segmentation
Annelids: “ringed forms”
20
Development
Sponges
• Multicellular
• No tissues or
organs
• No head or
mouth
22
Sponges
• No symmetry
• No tissues or
organs
• Cell layers are
loose federations
of cells
• Suspension
feeders
• Sexual and
asexual
23
Diversity of sponges
24
Reproduction
Ctenophora (comb jellies)
• Multicellular
• No tissues or
organs
• No head or
mouth
• Comb
26
Comb Jellies
Cnidaria
• Radial
symmetry
• Two true
tissue layers
(ectoderm
and
endoderm)
• Sac body plan
Cnidarians - jellyfish
Cnidarians
• 3 Classes
•
Jellyfish
•
Sea anemones, corals
•
Hydra
Cnidarian Body Plans & Life cycle
Tissue layers:
31
Epidermis
Gastrodermis
Cnidarian Nematocysts
32
Cnidarians - corals
33