General Zoology Unit Two

1. General Zoology Unit Two

2. Protista Eukaryotic, unicellular organisms Many have cell walls Autotrophic or heterotrophic Intracellular specialization (division of labor) Simple reflexes Found wherever life exists Asexual reproduction and conjugation

3. Protist Taxonomy Kingdom - Protista Phylum - Chlorophyta Ex. Volvox Phylum - Retortamonada Class – Diplomonadea Ex. Giardia Phylum - Axostylata Class – Parabasalea Ex. Trichomonas Phylum - Euglenozoa Class – Euglenoidea Ex. Euglena Class – Trypanosomatidea Ex. Trypanosoma

4. Protist Taxonomy Phylum - Apicomplexa Class – Coccidea Exs. Plasmodium, Eimeria, Toxoplasma Phylum - Ciliophora Exs. Paramecium, Stentor, Vorticella Phylum - Dinoflagellata Exs. Zooxanthella, Ceratium, Noctiluca Amebas – no longer a single taxonomic group Exs. Amoeba, Difflugia

5. Phylum - Chlorophyta Unicellular & multicellular algae Individual & colonial species Move with flagella Have chloroplasts, therefore autotrophs Volvox

6. Phylum - Retortamonada Class - Diplomonadea Unicellular individuals No mitochondria or Golgi bodies Move with several flagella Many are intestinal parasites, others live in anoxic conditions Giardia

7. Phylum - Axostylata Class - Parabasalea Unicellular individuals Have Golgi bodies, but no mitochondria Move with several flagella Have an axostyle Trichomonas

8. Phylum - Euglenozoa Class - Euglenoidea Unicellular individuals Have a pellicle Move with a single flagella Have contractile vacuoles & stigma Autotrophs that can be heterotrophic Euglena

9. Phylum - Euglenozoa Class - Trypanosomatidea Unicellular individuals Have a pellicle Move with a single flagella All members are parasitic Trypanosoma causes sleeping sickness (vector - tsetse flies) Trypanosoma

10. Phylum - Apicomplexa Class - Coccidea Unicellular individuals All members are parasitic No structure for locomotion Have rhoptries Plasmodium causes malaria (vector – Anopholes) Eimera infects fowl, resulting in coccidiosis Plasmodium Toxoplasma infects mammals

11. Phylum - Ciliophora Unicellular individuals Have a pellicle Cytoplasm made up of ectoplasm & endoplasm Have two nuclei Have contractile vacuoles Have digestive complexity Have structures for food gathering and protection Paramecium Most free living, some parasites

12. Ciliophoran Anatomy

13. Phylum - Dinoflagellata Unicellular individuals Move with two flagella Some autotrophic, some heterotrophic Form the producing base for plankton Form important symbiotic relationships Noctiluca

14. Amebas Unicellular individuals Not a monophyletic group Cytoplasm made up of ectoplasm & endoplasm Asymmetrical Have contractile vacuoles Move with pseudopods Some have tests, others are naked Amoeba Most free living, some parasites

15. Protist Nutrition Autotrophs – produce their own food Heterotrophs – two types Phagotrophs (holozoic) Osmotrophs (saprozoic) Phagosome – a food vacuole Contractile vacuole – water excretion

16. Surface area increases in multiples of two (L x W) Volume increases in multiples of three (L x W x D) Therefore the volume will increase quicker than the surface area during cell growth A high SA/V ratio means a cell can more easily maintain itself, can grow larger and become more complex The danger of a high SA/V ratio is that substances dangerous to the cell can more easily get in

17. Asexual Reproduction Asexual reproduction involves only one parent It has advantages in that it does not require a mate and the organism can exploit good environmental conditions

18. Asexual Reproduction These advantages enable the organism to use its energy resources most effectively on reproduction The major disadvantage is the lack of genetic diversity, possibly leading to decreased fitness

19. Sexual Reproduction Sexual reproduction involves two parents Its primary advantage is the genetic diversity it produces and the resulting increase in fitness

20. Sexual Reproduction The primary disadvantage of sexual reproduction is the inefficient use of energy in seeking and competing for mates This strategy many times does not allow for the best exploitation of ecological resources

21. Binary fission * asexual reproduction * one individual splits into two * cell division due to low SA/V ratio

22. Schizogony * asexual reproduction * one individual splits into many * Plasmodium carries out schizogony Budding * asexual reproduction * a tiny cell grows (buds) from the side of the parent

23. Conjugation * a process in which genes are recombined * two individuals exchange genetic material * no new individuals produced, but two are changed genetically a a a

24. Autogamy * asexual process * similar to conjugation * individual self fertilizes Syngamy * a sexual process * fertilization of a gamete by another

25. Trichomonas Vaginitis Trypanosoma Sleeping sickness Plasmodium Malaria Amoeba Dysentery Giardia Beaver fever Balantidium Colon perforations

26. Definitions Metazoans – multicellular animals Cell aggregates – metazoans with no tissues Eumetazoans – metazoans with tissues

27. Three Hypotheses for the Evolution of Metazoans Syncytical Ciliate Hypothesis – metazoans originated from ciliates Colonial Flagellate Hypothesis – metazoans originated from colonial flagellates Polyphyletic Origin Hypothesis – metazoans originated from several sources

28. Porifera Eukaryotic, metazoans Cell aggregates No true tissues or organs All aquatic, most marine Asymmetrical Body covered in pores Made up of several types of independent cells Skeleton of spicules, spongin and collagen All are sessile Asexual and sexual reproduction

29. Poriferan Taxonomy Kingdom - Animalia Phylum - Porifera Class – Calcarea (calcium carbonate spicules) Ex. - Sycon Class – Hexactinellida (silicon based spicules) Ex. - Euplectella Class – Demospongiae (spongin) Ex. – Spongilla, Cliona

30. Mesohyl Archaeocytes differentiate into other cells that produce the sponge skeleton (spicules, collagen and spongin)

31. Sponge Body Forms

32. Filter feeding organisms

33. Class - Calcarea Have calcium carbonate spicules All asconoid forms are in this class Some syconoid forms are in this class Most members of this class is of the leuconoid form

34. Class - Hexactinellida Have silicon based spicules Sometimes referred to as glass sponges All are deep sea forms Some members are of the syconoid form while others have the leuconoid form Euplectella

35. Class - Demospongiae Skeleton mainly spongin, with silicon spicules in some 95% of all extant sponges are in this class All members of this class are of the leuconoid form

36. Definitions Monoecious (one house) – both sexes in one individual (hermaphroditic) Dioecious (two house) - separate sexes housed in different individuals Gemmules – internal buds formed during adverse conditions

37. Sponge Reproduction Most sponges are monoecious Asexual reproduction – budding (external buds), gemmules and fragmentation Sexual reproduction – sperm released from individuals and eggs retained

38. Definitions Diploblastic – having two germ layers from which tissues and structures arise Ectoderm – outer germ layer that gives rise to tissues and structures that cover the outside Endoderm – inner germ layer that gives rise to tissues and structures that cover the inside Mesoglea – jelly-like substance found between the inner and outer layers

39. Gastrulation Ectoderm Mesoderm Endoderm Blastopore Blastula Gastrula Diploblastic

40. Cnidaria Eukaryotic, eumetazoans Diploblastic Have true tissues, but no organs All are marine Radially symmetrical (no cephalization) Polymorphic – two forms (polyp & medusa) Cnidocytes – stinging cells Have a nerve net Polyps are sessile, while medusae can move Asexual and sexual reproduction

41. Cnidarian Taxonomy Kingdom - Animalia Phylum - Cnidaria Class – Hydrozoa Ex. – Physalia, Obelia, Hydra, Gonionemus Class – Scyphozoa (true jellyfish) Ex. – Aurelia, Cassiopeia Class – Cubozoa Ex. – Carybdea Class – Anthozoa Ex. – Metridium, Gorgonia, Tubipora

42. Cnidarian Polymorphism

43. Polyp Anatomy

44. Gonionemus

45. Aurelia

46. Cnidocyte Anatomy

47. Class - Hydrozoa Most are marine and colonial in form Most forms exhibit alternation of generations between asexual polyps and sexual medusae, but some have only one or the other form Obelia Hydra Physalia

48. Class - Scyphozoa Referred to a the true jellyfish All are solitary Polyp stage is much reduced or absent Main body is cup shaped Aurelia

49. Class - Cubozoa Most are relatively small in size All are solitary Polyp stage is much reduced Main body is cube shaped Carybdea

50. Class - Anthozoa Polyp form predominant, no medusa stage Some are solitary, while others are colonial Many form zooxanthellae relationship with algae Most ecologically important group due to reef building Metridium Gorgonia Tubipora