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+ + CO3

2- → CaCO3

• calcium + carbonate ion• CO2 + H20 → H2CO3 (carbonic acid)• H2CO3 → H+ + HCO3-

• H+ + 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