Unit 5 Review

1. Unit 5 Review The Evolutionary History of Biological Diversity Not Complete!! (Nothing on plants yet)

2. The “RNA World” and the Dawn of Natural Selection • The first genetic material • Was probably RNA, not DNA

3. Ribozyme (RNA molecule) 3 Template Nucleotides Figure 26.5 5 5 Complementary RNA copy • RNA molecules called ribozymes have been found to catalyze many different reactions, including • Self-splicing • Making complementary copies of short stretches of their own sequence or other short pieces of RNA

4. The oldest known fossils are stromatolites • Rocklike structures composed of many layers of bacteria and sediment • Which date back 3.5 billion years ago

5. Chapter 27 Prokaryotes

6. Domain Archaea Domain Eukarya Domain Bacteria Proteobacteria Gram-positive bacteria Nanoarchaeotes Crenarchaeotes Euryarchaeotes Korarchaeotes Cyanobacteria Spirochetes Chlamydias Eukaryotes Gamma Epsilon Alpha Beta Delta Universal ancestor • A phylogeny of some major prokaryotetaxa based on molecular systematics:

7. Archaea • Archaea share certain traits with bacteria • And other traits with eukaryotes

8. Figure 27.1 Some “Extremophile” Archaea • Extreme thermophiles thrive in… • very hot environments

9. Chemical Recycling • Prokaryotes play a major role • In the continual recycling of chemical elements between the living and nonliving components of the environment

10. Figure 27.15 Symbiotic Relationships • Many prokaryotes • Live with other organisms in symbiotic relationships such as mutualism and commensalism Aren’t my symbiotic bacterial headlights cool?

11. Chapter 28 Protists

12. Endosymbiosis in Eukaryotic Evolution • Evidence supports endosymbiosis as an origin of eukaryote diversity:

13. Traditional …… and …… alternative hypotheis:

14. Chlorophyta Rhodophyta Diplomonadida Animalia Plantae Euglenozoa Fungi Parabasala Radiolaria Cercozoa Alveolata Stramenopila Amoebozoa (Viridiplantae) (Opisthokonta) Fungi Plants Ciliates Diatoms Euglenids Oomycetes Red algae Metazoans Diplomonads Brown algae Parabasalids Chlorophytes Radiolarians Entamoebas Kinetoplastids Golden algae Apicomplexans Foraminiferans Dinoflagellates Charophyceans Gymnamoebas Choanoflagellates Chlorarachniophytes Cellular slime molds Plasmodial slime molds • Arrows indicate probable instances of endosymbiosis • Note connections for fungi, plantae, & anamalia Ancestral eukaryote

15. CONJUGATION AND REPRODUCTION 2 Two cells of compatible mating strains align side by side and partially fuse. Meiosis of micronuclei produces four haploidmicronuclei in each cell. Three micronuclei in each cell disintegrate. The remaining micro-nucleus in each cell divides by mitosis. MEIOSIS The cells swap one micronucleus. Macronucleus Haploidmicronucleus Diploidmicronucleus Compatiblemates Diploidmicronucleus 3 7 4 9 8 2 5 6 1 MICRONUCLEARFUSION The cellsseparate. 7 8 Key Conjugation The original macro-nucleus disintegrates. Four micronuclei become macronuclei, while the other four remain micronuclei. Two rounds of cytokinesis partition one macronucleus and one micronucleus into each of four daughter cells. Three rounds of mitosis without cytokinesis produce eight micronuclei. Micronuclei fuse,forming a diploid micronucleus. Reproduction ALMOST sexual reproduction…

16. Sexual reproduction almost certainly evolved in the protists

17. Clade Viriplantidai • Most chlorophytes have complex life cycles • sexual and asexual reproductive stages

18. Phyla of two animal phyla, Cnidaria and Porifera, appear first. • The rest appear suddenly in the Cambrian 500 Annelids Sponges Molluscs Chordates Cnidarians Arthropods Brachiopods Echinoderms Early Paleozoic era (Cambrian period) Millions of years ago 542 Late Proterozoic eon Figure 26.17

19. Chapter 32 An Introduction to Animal Diversity

20. Figure 32.1 Welcome to Your Kingdom • Animals (except the sponges) are… • multicellular, heterotrophiceukaryotes with tissues that develop from embryonic layers

21. Only one cleavage stage–the eight-cell embryo–is shown here. In most animals, cleavage results in the formation of a multicellular stage called a blastula. The blastula of many animals is a hollow ball of cells. The zygote of an animal undergoes a succession of mitotic cell divisions called cleavage. 2 3 1 Blastocoel Cleavage Cleavage The endoderm of the archenteron de- velops into the tissue lining the animal’s digestive tract. 6 Cross section of blastula Eight-cell stage Blastula Zygote Blastocoel Endoderm The blind pouch formed by gastru- lation, called the archenteron, opens to the outside via the blastopore. 5 Ectoderm Gastrulation Gastrula Blastopore Most animals also undergo gastrulation, a rearrangement of the embryo in which one end of the embryo folds inward, expands, and eventually fills the blastocoel, producing layers of embryonic tissues: the ectoderm (outer layer) and the endoderm (inner layer). 4 Early Embryonic Development Figure 32.2

22. Single cell Stalk • The common ancestor of living animals • May have lived 1.2 billion–800 million years ago • May have resembled modern choanoflagellates, protists that are the closest living relatives of animals Figure 32.3

23. Deuterostome development (examples: echinoderms, chordates) Protostome development (examples: molluscs, annelids, arthropods) (a) Cleavage. In general, protostomedevelopment begins with spiral, determinate cleavage.Deuterostome development is characterized by radial, indeterminate cleavage. Eight-cell stage Eight-cell stage Spiral and determinate Radial and indeterminate Cleavage • In protostome development • Cleavage is spiral and determinate • In deuterostome development • Cleavage is radial and indeterminate Figure 32.9a

24. Coelom Formation Protostomes: Deuterostomes: Coelom Archenteron Coelom Mesoderm Mesoderm Blastopore Enterocoelous: folds of archenteron form coelom Schizocoelous: solid masses of mesoderm split and form coelom

25. newer animal phylogeny based mainly on molecular data Cnidaria Chordata Phoronida Mollusca Brachiopoda Annelida Ctenophora Nemertea Silicarea Ectoprocta Rotifera Calcarea Nematoda Arthropoda Echinodermata Platyhelminthes “Radiata” Deuterostomia Lophotrochozoa “Porifera” Ecdysozoa Bilateria Eumetazoa Metazoa Ancestral colonial flagellate Figure 32.11

26. Chapter 33 Invertebrates

27. Porifera Cnidaria Chordata Echinodermata Other bilaterians (including Nematoda, Arthropoda, Mollusca, and Annelida) Deuterostomia Bilateria Eumetazoa Ancestral colonial choanoflagellate Figure 33.2 • A review of animal phylogeny

28. Choanocytes. The spongocoel is lined with feeding cells called choanocytes. By beating flagella, the choanocytes create a current that draws water in through the porocytes. 5 Flagellum Choanocyte Collar Azure vase sponge (Callyspongia plicifera) Osculum Spongocoel. Water passing through porocytes enters a cavity called the spongocoel. 4 Phagocytosis of food particles Amoebocyte Porocytes. Water enters the epidermis through channels formed by porocytes, doughnut-shaped cells that span the body wall. 3 The movement of the choanocyte flagella also draws water through its collar of fingerlike projections. Food particles are trapped in the mucus coating the projections, engulfed by phagocytosis, and either digested or transferred to amoebocytes. 6 Spicules Epidermis. The outer layer consists of tightly packed epidermal cells. 2 Water flow Amoebocyte. Amoebocytes transport nutrients to other cells of the sponge body and also produce materials for skeletal fibers (spicules). 7 Mesohyl. The wall of this simple sponge consists of two layers of cells separated by a gelatinous matrix, the mesohyl (“middle matter”). 1 Phylum Porifera • Sponges are suspension feeders • Capturing food particles suspended in the water that passes through their body Figure 33.4

29. Medusa Mouth/anus Polyp Tentacle Gastrovascular cavity Gastrodermis Mesoglea Epidermis Body stalk Tentacle Mouth/anus Figure 33.5 Phylum Cnidaria • There are two variations on this body plan • The sessile polyp and the swimming medusa

30. Bilateral Animals • The vast majority of animal species belong to the clade Bilateria • Which consists of animals with bilateral symmetry and triploblastic development

32. Digestion is completed within the cells lining the gastro- vascular cavity, which has three branches, each with fine subbranches that pro- vide an extensive surface area. Pharynx. The mouth is at the tip of a muscular pharynx that extends from the animal’s ventral side. Digestive juices are spilled onto prey, and the pharynx sucks small pieces of food into the gastrovascular cavity, where digestion continues. Undigested wastes are egested through the mouth. Gastrovascular cavity Eyespots Ganglia. Located at the anterior end of the worm, near the main sources of sensory input, is a pair of ganglia, dense clusters of nerve cells. Ventral nerve cords. From the ganglia, a pair of ventral nerve cords runs the length of the body. Figure 33.10 Phylum Platyhelminthes - Turbellaria • The best-known turbellarians, commonly called planarians • Have light-sensitive eyespots and centralized nerve nets

33. Heart. Most molluscs have an open circulatory system. The dorsally located heart pumps circulatory fluid called hemolymph through arteries into sinuses (body spaces). The organs of the mollusc are thus continually bathed in hemolymph. Nephridium. Excretory organs called nephridia remove metabolic wastes from the hemolymph. The long digestive tract is coiled in the visceral mass. Visceral mass Coelom Intestine Gonads Mantle Stomach Radula. The mouth region in many mollusc species contains a rasp-like feeding organ called a radula. This belt of backward- curved teeth slides back and forth, scraping and scooping like a backhoe. Mantle cavity Shell Mouth Radula Anus The nervous system consists of a nerve ring around the esophagus, from which nerve cords extend. Gill Nerve cords Foot Mouth Esophagus Figure 33.16 - Lophotrochozoa Clade; Pylum Mollusca

37. Table 33.5 Phylum Arthropoda: • Molecular evidence now suggests • living arthropods consist of four major lineages that diverged early in the evolution of the phylum

38. 50 µm (c) (b) (a) Scorpions have pedipalps that are pincers specialized for defense and the capture of food. The tip of the tail bears a poisonous stinger. Dust mites are ubiquitous scavengers in human dwellings but are harmless except to those people who are allergic to them (colorized SEM). Web-building spiders are generally most active during the daytime. Figure 33.31a–c Cheliceriforms – Phylum Arthropoda • Most modern cheliceriforms are arachnids • A group that includes spiders, scorpions, ticks, and mites

39. Insecta – Phylum Arthropoda

40. Planktonic crustaceans known as krill are consumed in vast quantities by whales. (b) Crustaceans – Phylum Arthropoda • Planktonic crustaceans are primary consumers in many food chains • (a) copopods (among the most numerous animals) • (b) krill

41. Table 33.6

42. Figure 33.40a (a) A sea star (class Asteroidea) Sea Stars – Phylum Echinodermata • Sea stars, class Asteroidea • Have multiple arms radiating from a central disk • The undersurfaces of the arms • Bear tube feet, each of which can act like a suction disk

43. Chapter 34 Vertebrates

44. Dorsal,hollownerve cord Brain Notochord Musclesegments Mouth Anus Pharyngealslits or clefts Muscular,post-anal tail Figure 34.3 Derived Characters of Chordates • All chordates share a set of derived characters • Although some species possess some of these traits only during embryonic development

45. Chordates Craniates Vertebrates Gnathostomes Osteichthyans Lobe-fins Tetrapods Amniotes Echinodermata(sister group to chordates) Chondrichthyes(sharks, rays, chimaeras) Cephalaspidomorphi(lampreys) Amphibia(frogs, salamanders) Cephalochordata(lancelets) Actinopterygii(ray-finned fishes) Reptilia(turtles, snakes,crocodiles, birds) Urochordata(tunicates) Actinistia(coelacanths) Dipnoi(lungfishes) Myxini(hagfishes) Mammalia(mammals) Milk Amniotic egg Derived Characters of Chordates Legs Lobed fins Lungs or lung derivatives Jaws, mineralized skeleton Vertebral column Cranium Follow along on your own copy of this cladogram Brain Notochord & more Ancestral deuterostome

46. Ectoderm Notochord Dorsal, Hollow Nerve Cord • The dorsal nerve cord • Develops from a plate of ectoderm that rolls into a tube dorsal to the notochord • Develops into the central nervous system: the brain and the spinal cord

47. BF1 Otx Hox3 Nerve cord of lancelet embryo BF1 Hox3 Otx Brain of vertebrate embryo(shown straightened) Midbrain Forebrain Hindbrain Figure 34.6 • Gene expression in lancelets nervous system development is representative of that in vertebrates.

48. Slime glands Figure 34.9 Hagfishes • The least derived craniate lineage that still survives • Is class Myxini, the hagfishes

49. Gill slits Cranium Mouth Skeletal rods Figure 34.13 Derived Characters of Gnathostomes • Gnathostomes (“jaw-mouth”) • have jaws evolved from skeletal supports of the pharyngeal slits

50. Bonessupportinggills Tetrapodlimbskeleton Figure 34.19 The Origin of Tetrapods • In one lineage of lobe-fins • The fins became progressively more limb-like while the rest of the body retained adaptations for aquatic life