Unit 2 - Introduction to Animals PDF

Me want study ANIMALS now Introduction to Animals Chapter 30  Kingdom Animalia in the tree of life Eukaryotes Monophyletic clade Share a common ancestor with choanoflagellates Fungi also closely related Objective: 30-01...

Me want study ANIMALS now Introduction to Animals Chapter 30  Kingdom Animalia in the tree of life Eukaryotes Monophyletic clade Share a common ancestor with choanoflagellates Fungi also closely related Objective: 30-01 Fig 30.1  Characteristics of animals 1. Multicellular 2. No cell walls  Extracellular matrix allows for cohesion & communication 3. Heterotrophic Consume other organisms for carbon & energy 4. Obtains nutrition through ingestion  Fungi absorb, Plants photosynthesize 5. Most animals* have tissues *except sponges Objective: 30-01 Alpsdake 2013  Animal biomass 2 gigatons of carbon Objective: 30-01 Resnick & Zarracina 2018  Animal biomass lots of insects! Objective: 30-01 Davidmasp 2018  Closest relatives Which group do choanoflagellates belong to? Objective: 30-02 Fig 30.1; WK Weebly  Age of Animal Kingdom 600 million to 1.5 billion years old Diversification with Cambrian explosion (550 mya) 500-million- year-old organism with muscle tissue 570-million-year-old animal embryo fossils from China Objective: 30-01 Cunningham et al. 2017; Liu et al 2014  “But now the jury’s out on all the other weirdos.” Objective: 30-01 Bobrovskiy et al. 2018  Animal life cycle Most reproduce sexually – Some can also reproduce asexually Human gametes (egg and sperm) Diploid (2N) stage is dominant Haploid (1N) gametes Early embryotic development Budding hydra – Cleavage, blastula stage, gastrulation, gastrula stage Objective: 30-01 D. Phillips; Lifetrance 2009  Animal reproduction 80% of animals go through metamorphosis Objective: 30-01 Figure 30.12  Animal phylogeny – important! Lophotrochozoa Ecdysozoa Current Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. organization and classification Mollusca Rotifera Chordata Annelida Echinodermata Arthropoda Lophophorata Platyhelminthes Nematoda Porifera Cnidaria and Ctenophora Based on segmentation segmentation Loss of coelom comparisons of segmentation DNA sequences It is similar to the Lophophore or trochophore larva Ecdysis morphological Protostome development Deuterostome phylogeny that development, endoskeleton preceded it (pre- Radiata Bilateral symmetry Triploblasty 1997) Parazoa Tissues diploblasty Cephalization Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Animal phylogeny Monophyletic Share a common ancestor with Choanoflagellates Multicellularity shared trait with all animals Objective: 30-01 Figure 30.2  Choanoflagellates Protists Single-celled or colonial Share a common ancestor with animals Live in salt & fresh water Objective: 30-02  Similarities with Phylum Porifera Objective: 30-01 Figure 30.3  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Protostome development Deuterostome development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Tissues Collection of specialized cells that are isolated from other tissues by membranous layers Metazoa – all animals Parazoa – animals with no specialized tissues – Phylum Porifera (sponges) Eumetazoa – have more than one type of tissue – All animals except Phylum Porifera (sponges)  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Parazoa Lophophore or trochophore larva Ecdysis No tissues Protostome development Deuterostome development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Tissues Separate collections of specialized cells Tissues are derived from embryonic germ layers Formed after gastrulation Objective: 30-05 & 30-06  Animal blastula development Fertilized egg cell Cleavage - mitotic cell division with NO growth of cell ball Cross-section of the blastula - a hollow ball of cells Objective: 30-03 & 30-04  Animal blastula development Egg Blastula Objective: 30-04  Cleavage – no change in ball size Objective: 30-03  Gastrula formation Blastula Gastrula blastocoel eEndoderm Ectoderm Gastrulation blastopore Gastrulation - a rearrangement of the embryo; folds into the blastocoel, formation of germ layers Objective: 30-04  Gastrula formation Zygote 4 cell stage 8 cell stage Blastula Blastula Gastrula Objective: 30-04  Germ layers Embryonic layers that become various tissues in the animal body Formed after gastrulation – Ectoderm – outer covering & nervous tissue – Endoderm – lining & organs of the digestive tract – Mesoderm – circulatory system, muscles, some organs Diploblastic organisms only have 2 layers  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. 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Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Parazoa No tissues Protostome development Deuterostome development, Radially symmetric, no coelom (body cavity) endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations Diploblasty – two germ layers Figure 30.4  Phylum Cnidaria  Jellyfish, coral, sea anemone, hydra  Diploblastic  Radial symmetry  Neural net  Body symmetry = radial Sessile or Planktonic (floating) RADIAL Experience environment from all sides BILATERAL Have central nervous system Objective: 30-05 & 30-06  Body symmetry -- examples Objective: 30-05 & 30-06 Figure 30.5  Neural net versus central nervous system Objective: 30-05 & 30-06 Figure 30.8 Objective: 30-05 & 30-06  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Protostome development Deuterostome development, Radially symmetric, no coelom endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Protostome development Deuterostome development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Triploblasts – three germ layers Have three layers – Ectoderm – outer covering & nervous tissue – Endoderm – lining & organs of the digestive tract – Mesoderm – circulatory system, muscles, some organs Have a body cavity – coelom – a fluid-filled space separating the digestive tract from the outer body wall lined with mesoderm Objective: 30-07  Coelom types Coelomate – body cavity is completely lined with mesoderm Acoelomate – no body cavity (lost during evolution) Pseudocoelomate – body cavity has only one layer of mesoderm (not completely surrounded) Objective:30-07 Objective: 30-07 Figure 30.10  Why coelom (body cavity)? Fluid in cavity cushions organs Acts like a skeleton in some soft-bodied animals Provides space for organs to grow & move independently from the outside of the body Objective: 30-07 Figure 30.9  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Protostome development Deuterostome development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Fate of the blastopore Protostomes – Blastopore (first hole in blastula) becomes the mouth – Cleavage is spiral & determinate Deuterostomes – Blastopore (first hole in blastula) becomes the anus – Cleavage is radial & indeterminate Objective: 30-08  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva mouth first Protostome development Deuterostome butt first development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Cleavage – spiral vs radial Protostomes Deuterostomes Objective: 30-08  Determinate cleavage Remove a cell from a 4-cell embryo Both cell balls die Missing critical tissues because cell destiny “determined” Objective: 30-08  Indeterminate cleavage Remove a cell from a 4- cell embryo Both cell balls produce complete organisms Cell destiny flexible Objective: 30-08  Fate of the blastopore archenteron = primitive digestive tube Objective: 30-08  Protostome “superphyla” (unofficial taxonomic grade of phyla descended from common ancestor) Lophotrochozoa – “lophos” is Greek for crest, refers to ciliated structure – Some have trochophore larvae before metamorphosis and/or a lophophore stage as an adult Ecdysozoa – the skin (or cuticle) shedding protostomes – secrete external skeletons (exoskeletons) – sheds & secretes new exoskeleton with growth  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. 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Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Protostome development Deuterostome development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephelization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Lophotrochozoa Objective: 30-09 Figure 31.5  Protostome “superphyla” (unofficial taxonomic grade of phyla descended from common ancestor) Lophotrochozoa – “lophos” is Greek for crest, refers to ciliated structure – Some have trochophore larvae before metamorphosis and/or a lophophore stage as an adult Ecdysozoa – the skin (or cuticle) shedding protostomes – secrete external skeletons (exoskeletons) – sheds & secretes new exoskeleton with growth  Ecdysis Objective: 30-09 Niland 2012; Stemonitis 2006  Fate of the blastopore Protostomes – Blastopore (first hole in blastula) becomes the mouth – Cleavage is spiral & determinate Deuterostomes – Blastopore (first hole in blastula) becomes the anus – Cleavage is radial & indeterminate Objective: 30-08  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Protostome development Deuterostome development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Deuterostome Superphylum Has all triploblastic characteristics Bilaterally symmetrical, coelom development, central nervous system, cephalization Includes two phyla – Phylum Echinodermata Sea stars, sea urchins, & sea cucumbers – Phylum Chordata Lancelets, tunicates, & vertebrates  Bilaterally symmetrical Yes as larvae! Adults are pentaradial Objective: 30-09  Segmentation Independently evolved at least three times in animals Allows for specialization of sections Objective: 30-10  Lophotrochozoa Ecdysozoa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mollusca Chordata Annelida Echinodermata Arthropoda Platyhelminthes Nematoda Porifera segmentation Cnidaria segmentation Loss of coelom segmentation Lophophore or Ecdysis trochophore larva Protostome development Deuterostome development, endoskeleton Radiata Bilateral symmetry Triploblasty Parazoa Tissues Cephalization diploblasty Coelom Central Nervous system Multicellularity Ancestral colonial choanoflagellate Critical innovations  Animal diversity The majority of named species are animals – 1.3 million extant (living) species – Total number maybe as high as 100-200 million There are 35 known animal phyla – We will focus on 9  Our 9 phyla of interest Porifera (sponges) Cnidaria (jellyfish, coral, anemones, hydra) Lophotrochozoa – Platyhelminthes (flatworms) – Annelida (segmented worms) – Mollusca (snails, slugs, bivalves, cephalopods) Ecdysozoa – Nematoda (roundworms) – Arthropoda (spiders, crustaceans, insects) Deuterostomes – Echinodermata (sea stars, sea urchins, sea cucumbers) – Chordata (lancelets, tunicates, vertebrates) Review on own Diversification in Animals – Sensory organs (Table 30.2) – Ecological roles (Table 30.3) – Feeding strategies (Table 30.4) – Limb structure (Table 30.5) – Reproductive strategies (Table 30.6)