What is an animal? Mul.cellular heterotrophs: feed by inges&on. How does this differ from plants, fungi, pro.sts?

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1 What is an animal? Mul.cellular heterotrophs: feed by inges&on. How does this differ from plants, fungi, pro.sts?

2 What is an animal? Carbohydrates stored as glycogen Polysaccharide of glucose (no, you do not need to know this structure)

3 What is an animal? No cell walls Cells supported by structural proteins: collagen Extracellular matrix, supports.ssues, gives cells structure from outside Triple- helix structural protein

4 What is an animal? Nerve and muscle.ssue Impulse & movement

5 What is an animal? Generally, most have sexual reproduc.on from anisogamous or heterogamous gametes.

6 What is an animal? Development Egg + Sperm Zygote cleavage Blastula Gastrula Larva or juvenile Adult This development regulated by Hox genes

7 The vast majority of animal species are marine Only truly terrestrial* animals come from 5 phyla Mollusca Annelida Onychophora Arthropoda Chordata *Does not include internal parasites nor taxa needing constant external moisture Animal Diversity

8 Animal Origins Monophyle&c Sister taxon Choanoflagellates (pro.st protozoan) Colonial, flagellated pro.st ancestor

9 Animal Origins Gastrula- like infolding into two layers Increased specializa.on of cells and.ssues beginning with soma&c vs reproduc&ve

10 Animal Origins Molecular evidence: Suggests divergence from fungi ~1 bya Common ancestor of animals mya

11 Animal Origins Fossil evidence: Possible trace fossils ~900 mya Ediacaran fauna mya Animals??? Definite animal fossils (about 1/2 of phyla) appear during Cambrian Explosion.

12 The Cambrian Explosion Why so sudden? 1. Predator- Prey interac.ons and coevolu.onary arms races. 2. Increase in atmospheric oxygen allows for larger animals with higher metabolic rates. 3. Key innova&on of Hox genes allows rapid diversifica.on of developmental pathways. Animal Origins

13 Morphological Trends Symmetry Radial vs bilateral Radial Top and bofom only- - no leg or right Likely ancestral trait: Cnidarians, Ctenophores

14 Morphological Trends Symmetry Radial vs bilateral Bilateral Top- bofom, forward- backward, leg- right Allowed cephaliza&on, more ac.ve lifestyle.

15 Morphological Trends Tissues Porifera or Parazoa (sponges) lack true.ssues (this is a unique development)

16 Gastrula.on Germ layers are formed by the process of gastrula&on One end of blastula folds inward, eventually produces layers of embryonic.ssue

17 Blastula is a mul.- cellular embryonic stage that is typically a hollow ball of cells that surrounds a cavity called a blastocoel Gastrula.on

18 Gastrula.on The invagina.on or gastrula.on results in the gastrula stage The pouch formed is called the archenteron and the opening to the outside is called the blastopore

19 Animals with only ectoderm and endoderm have only gastrula.on as germ layer forma.on Cnidaria (jellies) and Ctenophora (comb jellies) Diploblas&c Gastrula.on

20 All bilateral animals have a third germ layer, the mesoderm Forms muscles and most organs between diges.ve tract and the outer covering. Triploblas&c Gastrula.on

21 Body Cavity: The Coelom Most triploblas.c animals have a body cavity Fluid- or air- filled space separa.ng the diges.ve tract from the outer body wall. This is the coelom

22 Body Cavity: The Coelom The coelom forms from.ssue derived from mesoderm COELOMATES: Mesoderm connects dorsally and ventrally and provides a complete lining of the coelom

23 Body Cavity: The Coelom The coelom forms from.ssue derived from mesoderm PSEUDO- COELOMATES: Coelom is lined with mesoderm (outside) and endoderm (inside)

24 Body Cavity: The Coelom The coelom forms from.ssue derived from mesoderm ACOELOMATES: No true body cavity Ogen sog- bodied organisms.

25 Body Cavity: The Coelom All three groups (Coelomates, Pseudocoelomates, and Acoelomates) are polyphyle&c. Body cavity (coelom) also coincides with complete diges.ve tract (mouth, anus) and circulatory system (vessels or sinuses)

26 Coelomates: Protostomes & Deuterostomes Classic division in Bilateria Differences Pafern of early cell division To&potency in early cell development The forma.on of the coelom Fate of the blastopore

27 Coelomates: Protostomes & Deuterostomes Protostomes Early cell division is via spiral cleavage Deuterostomes Early cell division is via radial cleavage

28 Coelomates: Protostomes & Deuterostomes Protostomes Fate of cells is determined at early cleavage stages: Determinate cleavage Deuterostomes Cells at early cleavage stages remain to&potent: Indeterminate cleavage

29 Coelomates: Protostomes & Deuterostomes Protostomes Solid mass of mesoderm splits to form coelom: schizocoelous Deuterostomes Coelom forms from mesodermal outpocke.ngs of the archenteron: enterocoelous

30 Coelomates: Protostomes & Deuterostomes Protostomes Blastopore becomes mouth Deuterostomes Blastopore becomes anus

31 General Classifica.on of Animalia Currently considerable debate on rela.onships between animal phyla. Remember, Animalia is monophyle.c.

32 General Classifica.on of Animalia Sponges branch first, form the Porifera or Parazoa. Morphology and molecules disagree about monophyly Generally considered paraphyle.c Animalia without true.ssues Everything else form Eumetazoa Animalia with true.ssues

33 General Classifica.on of Animalia Radiata are paraphyle.c: Cnidaria & Ctenophora Radial symmetry Diploblas.c Bilateria are monophyle.c Bilateral symmetry Triploblas.c

34 General Classifica.on of Animalia Bilateria divided into four groups: Acoela Deuterostomia Echinodermata Chordata Ecdysozoa Nematoda Arthropoda Lophotrochozoa Platyhelminthes Ro.fera Ectoprocta Brachiopoda Mollusca