zoology introduction lecture notes.pptx.

zoology introduction

1. 1 - 1 Integrated Principles of Zoology, 14/e Cleveland P. Hickman, Jr. Larry S. Roberts Allan Larson Helen I'Anson David Eisenhour

2. Zoology: The scientific study of animal life Knowledge of the animal world is gained by actively applying important guiding principles to our investigations Exploration of the animal world depends critically on our questions , methods , and principles 1- 2 The Uses of Principles

3. General Properties of Living Systems 1- 3 Complexity and Hierarchical Organization: Living systems demonstrate a unique and complex hierarchical organization In living systems there exists a hierarchy of levels that includes: Macromolecules Cells Organisms Populations Species

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5. General Properties of Living Systems 1- 5 Metabolism: Living organisms maintain themselves by acquiring nutrients from their environments Metabolic processes include: Digestion Energy production (Respiration) Synthesis of required molecules and structures by organisms

6. General Properties of Living Systems 1- 6 Development: All organisms pass through a characteristic life cycle Development describes the characteristic changes that an organism undergoes from its origin to its final adult form

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8. General Properties of Living Systems 1- 8 Environmental Interaction: All animals interact with their environments Ecology : The study of organismal interaction with an environment All organisms respond to environmental stimuli, a property called irritability

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10. Ge ne ral P r o p er t ies of Living Systems 1- 10 Movements even at the cellular level are required for: R e product i on Growth Responses to stimuli Development in multicellular organisms On a larger scale: Entire populations or species may disperse from one geographic location to another over time

11. Zoology As Part of Biology Characteristics of Animals: Eukaryotes : cells contain membrane-enclosed nuclei Heterotrophs : Not capable of directly manufacturing their own food and must rely on external food sources Cells lack cell walls 1- 11

12. Cell Theory All living organisms are composed of cells All cells come from pre-existing cells - remember this is a theory 4- 12 Cell Concept

13. All cells arise from the division of preexisting cells Cell division - Mitosis (somatic cells) Fig 3.65 Meiosis (sex cells) Division of the cytoplasm ( cytokinesis ) In most multicellular organisms, all cells originate from the zygote Single cell resulting from union of an egg and a sperm (gametes) 4- 13 Mitosis and Cell Division

14. ■ 4- 14 Cellular Metabolism The chemical processes that occur within living cells Concept of energy fundamental to all life processes Energy cannot be seen Can be identified only by how it affects matter Energy and the Laws of Thermodynamics

15. Chromosomal Basis of Inheritance 5- 15 Meiosis: Reduction Division of Gametes Sex cells ( gametes ) transmit genetic information from parents to offspring in sexually reproducing organisms Chromosomes occur in pairs: homologs One member or the pair is donated by the mother, the other by the father Homologs Contain similar genes encoding the same set of characteristics Usually have the same size and shape

16. Meiosis Fig 5.12 Special type of nuclear division Associated with gamete production Genetic material replicates once followed by 2 successive nuclear divisions Produces 4 daughter cells Each with only 1 member of each homologous chromosome pair or 1 set of chromosomes ( haploid ) 5- 16 Chromosomal Basis of Inheritance

17. Nature of the Reproductive Process 7- 17 Reproduction is one of the properties of life Two modes of reproduction are recognized Asexual Sexual

18. Asexual Reproduction Involves only one parent No special reproductive organs or cells Genetically identical offspring are produced Production of offspring is simple, direct, and rapid Ensures rapid increase in numbers 7- 18 Nature of the Reproductive Process

19. Asexual Reproductive Methods Binary Fission Common among bacteria and protozoa The parent divides by mitosis into two parts Each grows into an individual similar to the parent Multiple Fission Nucleus divides repeatedly Cytoplasmic division produces many daughter cells 7- 19 Nature of the Reproductive Process

20. Sporogony (Spore Formation) Form of multiple fission in parasitic protozoa (like Plasmodium / malaria) Budding Unequal division of an organism Bud is an outgrowth of the parent Develops organs and then detaches 7- 20 Nature of the Reproductive Process

21. Fragmentation Multicellular animal breaking into many fragments that become a new animal Starfish examples are known 7- 21 Nature of the Reproductive Process

22. Fragmentation

23. Spore Formation

24. Advantages and Benefits of Asexual Reproduction • No need to spend time and energy finding a mate • No need to use energy resources producing eggs and sperm that potentially would never be used Disadvantages and Costs of Asexual Reproduction • Lack of variation within the population means the species is less likely to survive after environmental change

25. Sexual Reproduction Generally involves two parents Special germ cells unite to form a zygote S exual reproduction recombines parental characters A richer, more diversified population results In haploid asexual organisms Mutations are expressed and selected quickly In sexual reproduction Normal gene on the homologous chromosome may mask a gene mutation 7- 26 Nature of the Reproductive Process

26. Hermaphroditism Both male and female organs in the same individual Many sessile, burrowing and/or endoparasitic invertebrates and some fish Most avoid self-fertilization Exchange gametes with member of same species Each individual produces eggs Hermaphroditic species could potentially produce twice as many offspring as dioecious species Sequential Hermaphroditism A genetically programmed sex change occurs with an individual organism - clownfish example ! 7- 27 Nature of the Reproductive Process

27. Parthenogenesis Development of an embryo from an unfertilized egg Male and female nuclei fail to unite after fertilization Avoids the energy and dangers of bringing two sexes together Narrows the diversity available for adaptation to new conditions Ameiotic Parthenogenesis No meiosis occurs Egg forms by mitosis 7- 28 Nature of the Reproductive Process

28. Meiotic Parthenogenesis Haploid ovum formed by meiosis Develops without fusion with male nucleus Sperm may be absent or May only serve to activate development In some species, the haploid egg returns to a diploid condition by chromosomal duplication or autogamy (rejoining of haploid nuclei) 7- 29 Nature of the Reproductive Process

29. Haplodiploidy - can determine sex Occurs in bees, wasps and ants Queen controls whether the eggs are fertilized or unfertilized Fertilized eggs Become female workers or queens Unfertilized eggs become drones 7- 30 Nature of the Reproductive Process