Download ANIMALIA

ANIMALIA
• Domain Eukarya, Kingdom Animalia
• Linnaeus classification: 2 Kingdoms
(mid-1700s)
• Whittaker classification: 5 Kingdoms
(1959)
ANIMALIA
• Woese classification: 3 Domains, many
Kingdoms (1990); Figs. 26.21, 27.16
ANIMALIA
• Eukarya: Opisthokonta: Animalia
• one of many descendant clades of
ancestral eukaryote
• multicellular fungi and at least two
unicellular protist groups are close
relatives; Figs. 31.8
• multicellularity evolved at least twice
within eukaryotes
ANIMALIA
•
•
•
•
•
•
•
Kingdom Animalia (= Metazoa)
multicellular
around 35 phyla (plural of Phylum)
all but 1 invertebrates (no “backbone”)
9 phyla in this course
represent major clades
represent characters that include some
of the major evolutionary changes
ANIMALIA
• what is an animal?
• monophyletic taxon; Hox genes
(positional info during development:
what body parts go where)
• multicellular; permits large size
• heterotrophic: ingestion
• eat other organisms (live/dead) using a
mouth
• structural proteins support; not cell walls
ANIMALIA
•
•
•
•
diploid (2n) stage dominates life cycle
motile sperm, nonmotile egg
most have muscle, nerve cells
incredible variations on a few basic
body plans
• Fig. 32.10
ANIMALIA
• deep time: major diversification between
535-525 mya (in Cambrian Period);
Table 25.1
ANIMALIA
• competing phylogenetic hypotheses
• morphological (= anatomical),
developmental (= embryological)
characters; Fig. 32.10
• molecular characters, some morph/dev;
Fig. 32.11
ANIMALIA
• debate between Fig. 32.10 & 32.11:
homologous vs. homoplasous
• research is continuing
• basic body plan characters
TISSUES
• group of similar cells; common
structure/function (e.g. leaf epidermal
cells, cardiac muscle cells)
• absence vs. presence: non-Eumetazoa
vs. Eumetazoa
• "Phylum" Porifera: sponges
• Eumetazoa: "true animals"; us
SYMMETRY
• 2 types; Fig. 32.7
• radial: multiple planes through central
axis gives mirror image
• bilateral: only one plane through central
axis gives mirror image
• bilateral: right, left sides
SYMMETRY
• Phylum Cnidaria (hydras, jellies, corals);
eumetazoans with radial symmetry
• Bilateria: all other Eumetazoa; us
GERM LAYERS
• germ: something serving as an origin
• # of germ (body) layers
• 3 types: ectoderm, endoderm,
mesoderm; Fig. 32.8
• Cnidaria: 2 (diploblastic: ectoderm &
endoderm)
• Bilateria: 3 (triploblastic: ectoderm,
endoderm, mesoderm)
BODY CAVITY
•
•
•
•
coelom (hollow): a body cavity
no coelom (acoelomates); Fig. 32.8
Phylum Platyhelminthes (flatworms)
pseudocoelom (pseudocoelomates):
coelom not totally lined by mesoderm
• Phylum Nematoda (roundworms)
• coelom (coelomates): coelom totally
lined by mesoderm
• 5 other Phyla (of 9)
MOUTH ORIGIN
•
•
•
•
•
•
•
•
early embryonic development; Fig. 32.2
zygote initially undergoes cleavage
cleavage: mitosis without cell growth
blastula: hollow ball; blastocoel
gastrulation: involves infolding
gastrula: germ layers
archenteron: embryonic gut
blastopore: opening into archenteron
MOUTH ORIGIN
•
•
•
•
•
blastopore becomes mouth; Fig. 32.9
protostome: first mouth
Phylum Mollusca (clams, snails, squids)
Phylum Annelida (segmented worms)
Phylum Arthropoda (crustaceans,
insects, spiders)
MOUTH ORIGIN
• mouth from secondary opening in
gastrula
• deuterostome: second mouth
• Phylum Echinodermata (starfish, sea
urchins)
• Phylum Chordata (tunicates, lancelets,
vertebrates; us)
COELOM FORMATION
• protostomes or deuterostomes; Fig.
32.9
• coelom formation in gastrula; mesoderm
• protostomes: schizocoelous; “split”
• mesoderm splits; forms the coelomic
cavities
• deuterostomes: enterocoelous; “gut”
• mesoderms buds off the archenteron to
form coelomic cavities
CLEAVAGE TYPE
• two components of cleavage; Fig. 32.9
• 1. spiral or radial cleavage
• spiral: cell division plane diagonal to
embryo's vertical axis; cells offset
• radial: cell division plane both parallel
and perpendicular to embryo's vertical
axis; cells not offset
CLEAVAGE FATE
• 2. determinate or indeterminate
cleavage
• determinate: fate of embryonic cell
determined early
• indeterminate: fate of embryonic cell
determined later; identical twins
• protostomes: spiral, determinate
• deuterostomes: radial, indeterminate
ALTERNATIVE HYPOTHESES
•
•
•
•
Figs. 32.10, 32.11
some groups the same
Animalia, Eumetazoa monophyletic
Deuterostomia monophyletic, but
differences in membership
• presence/type of coelom is
homoplasous in 32.11
MOLECULAR PHYLOGENY
• defined by shared derived homologous
gene sequences
• Lophotrochozoa; Fig. 32.13
• lophophore: feeding structure
• trochophore: larval stage
• Ecdysozoa; Fig. 32.12
• secrete exoskeletons
• ecdysis: shed/molt; necessary to grow
SUMMARY
• think about where the homologous characters
would map; concept Fig. 32.4 page 665
• tissues: absent or present
• symmetry: radial or bilateral
• germ layers: 2 or 3
• coelom type: acoelomate, pseudocoelomate,
or coelomate
• protostome or deuterostome
– mouth origin: blastopore or secondary opening
– coelom formation: schizocoelous or enterocoelous
– cleavage: spiral or radial, determinate or
indeterminate
ANIMAL PHYLA
•
•
•
•
•
key adaptations; structure and function
acquire/distribute oxygen, water, food
get rid of wastes (CO2, metabolic)
sense the environment
respond to the environment
– movement
– protection
• reproduce
PORIFERA
• "Phylum" Porifera (sponges); lecture
links
PORIFERA
• most marine; many live with coral reefs
• no fixed body shape, no symmetry
• multicellular: specialized cells, but no
true tissues
• cellular interdependencies, but loose
coordination
• very successful: complexity of form not
necessary for evolutionary success
PORIFERA ANATOMY
• Fig. 33.4
• choanocytes: flagellated collar cells
• suspension feeders: create water currents,
trap food, intracellular digestion
• basic anatomy: water canal system
• ostia (ostium): small pores (pore-bearing)
• sequential hermaphrodites
• sessile (attached to a substrate) adult
• dispersing larval stage
PORIFERA
•
•
•
•
•
“alternative” animals; used to be ignored
colorful: yellow, red, violet, etc; toxicity
biochemical complexity
biotoxins for protection, competition
diversity of interest to natural products
chemists, pharmacologists
• sponge conservation biology important
• concentrate nutrients in coral reef
ecosystem
PORIFERA
• what is sister group to animals?
– similarity between choanocyte and
choanoflagellates
• Choanoflagellata: protist-like, colonial,
flagellated; Fig. 32.3
• choanocyte is the shared derived
homologous character
CNIDARIA
• Phylum Cnidaria; lecture links
• hydras, jellies, sea anemones, coral
CNIDARIA
• most marine, very successful
• radial symmetry; Fig. 33.5
• good adaptation when:
– sessile
– planktonic (drifting in currents)
• diploblastic: 2 germ layers
CNIDARIA
• tissues, but no organs
– pseudomuscle tissue
– nerve net tissue; Fig. 49.2
• Fig. 33.8: 2 body forms; taxa vary in which
form is dominant
• polyp form: cylindrical, mouth-up
– hydras, sea anemones, corals
• medusa form: bowl-like, mouth-down
– jellies
• cnidocyte: a cell specialized for defense,
capture of prey; Fig. 33.6
CNIDARIA
• coral animals secrete calcium carbonate
exoskeleton: reef
• home for millions of other species
• 75% of coral reefs threatened
http://coralreefwatch.noaa.gov/satellite/
CNIDARIA
• photosynthetic endosymbiotic
dinoflagellates; live inside coral cells
CNIDARIA
• mutualism: symbiosis where both
benefit
• bleaching: breakdown of mutualism
• global warming: burn oil, coal → CO2 ↑
• global warming → warmer waters →
bleaching
ACIDIFICATION
• ocean acidification via carbonic acid
• calcium carbonate shells can dissolve
• reduced ability to even form calcium
carbonate shells
ACIDIFICATION
•
•
•
•
•
•
•
•
calcium carbonate (CaCO3) organisms
Ca2+ + CO32- → CaCO3
calcium + carbonate ion
CO2 + H20 → H2CO3 (carbonic acid)
H2CO3 → H+ + HCO3H+ + CO32- → HCO3- (bicarbonate ion)
reduction in carbonate ion availability
can't secrete CaCO3 shell
http://news.bbc.co.uk/1/hi/sci/tech/7933589.stm
Nature
10 March
2011
Nature 10 March 2011; dark blue line is current path to 800 ppm