Zoology : Introduction to Animals Ch.27

1. Zoology : Introduction to Animals (Ch.27) Zoology is the study of animals. This includes the study of the following characteristics of animals : Structure/function Classification Lifestyle

2. General Features of Animals Animals exhibit the following features : Heterotrophy * Tissues Mobility * Absence of cell wall Multicellularity Diploidy Sexual reproduction Blastula formation

3. Animal Features Heterotrophy : animals can�t make their own food, and must obtain their food Mobility: animals have the ability to move Multicellularity: animals are composed of many cells Diploidy: adults have two copies of each chromosome

4. Animal Features Sexual reproduction : animals reproduce sexually, egg cell and sperm cell Absence of a Cell Wall: animal cells lack a cell wall Blastula formation: after fertilization the zygote produced from the sperm and egg forms a hollow ball of cells (blastula)

5. Animal Cell Specialization Most animals reproduce sexually with an egg and a sperm uniting to form a �zygote�. This zygote cell then divides into solid ball of cells (morula) and then a hollow ball (blastula)

6. Animal Cell Specialization Cells in the morula have the ability to change into specialized cells for the animal. ( Hair cells, muscle cells, nerve cells, etc.) These original cells capable of being specialized cells are called �stem cells�.

7. Animal Cell Specialization As a result of the DNA in the cells, animals show a wide variety of differences. The development of the animal through its genetic code and environment shapes the animals anatomy and behavior.

8. Animal Embryonic Development Upon fertilization of an animal egg by a sperm, a zygote is formed. The chromosomes in the egg and the chromosomes in the sperm combine to form a diploid (2) set of chromosomes containing genes for the zygotes development

9. Embryonic Development Once a zygote is formed, it appears that genes found in the egg control the development of the zygote into a blastula. Studies have shown that proteins produced by genes from the egg determine the initial differentiation of cells into specialized body parts.

10. Embryonic Development There are typically four stages of embryonic development: Cleavage Patterning Differentiation Growth

11. Embryonic Development Cleavage: the process of the zygote dividing, dividing again, and at different rates at each end of the cell to produce a ball of approximately a thousand cells.(blastula)

12. Embryonic Development Patterning: In this stage cells organize themselves into layers and masses. This process is called �gastrulation�

13. Embryonic Development

14. Embryonic Development Differentiation: the third stage of embryonic development includes the division of cells to form specialized structures such as nerve cells, blood cells, skin cells, etc.

15. Embryonic Development Growth : the final stage of embryo development results in division of specialized cells to produce organs, organ systems, and the animal.

16. Embryonic Development Studies have shown that proteins built by the eggs genes determine the steps of development. In some studies it was found that the addition of a protein during the patterning stage will cause an animal to have two heads, two tails, no skin, etc.

17. Animal Embryonic Development In most all animals the four stages described are observed in their development.

18. Sea Urchin Embryonic Development Picture A represents a zygote, and picture F a late stage blastula.

19. Animations/Photos of Different Animal Embryonic Development http://www.luc.edu/depts/biology/dev/devm.htm

20. Animal Features Tissues: animal cells are organized into tissues Example of tissues : muscle tissue, skin tissue, nerve tissue, etc.

21. Body Symmetry Animals have a body plan or shape. Sponges have the simplest body plan. Sponges have an �irregular� or asymmetrical. Other animals have a form of symmetry to their bodies

22. Body Symmetry Radial Symmetry : some animals have body parts arranged around a central axis. Some aquatic animals show this symmetry. Ex) sea anemone, jellyfish, etc.

23. Body Symmetry Bilateral symmetry: a body plan of all other animals which show distinct right and left halves. Cephalization : having nerves, �brain� at one end of the body

24. Symmetry Activity Pair up with a classmate and in your journal do the �quick lab� on page 599 to practice the type of symmetry animals have.

25. Internal Body Cavity Animals with bilateral symmetry have one of three basic body plans: Acoelomate : animals with no body cavity. Pseudocoelomate : animals with a �false�body cavity Coelomate : animals with a body cavity within the mesoderm.

26. Body Segmentation Segmented animals have similar units called �segments�. Then kingdom Animalia contains about 35 major divisions or phyla. Phylogenetic tree : a branching diagram to show animal relationships based upon the anatomy of living animals

27. End of Section #1 In your journal do the section 1 review. (Pg. 603)

28. Section 2 : Animal Body Systems Animals need to perform specific functions for survival. The major functions they need are : Digestion, respiration, circulation, conduction of nerve impulses, support, and excretion

29. Digestion Animals need to acquire energy through food. Most animals digest or break down their food within a digestive cavity or system. Enzymes play an important role in the digestion of food. Simple animals have a gastrovascular cavity, while others have a digestive tract.

30. Respiration Repiration is the uptake of oxygen and the release of carbon dioxide gas. Simple animals achieve this through diffusion, while other animals achieve this with gills, or lungs.

31. Circulation Many materials must be transported to and from the cells of animals. Two types of circulatory systems achieve this : Open circulatory system and closed circulatory systems. Open : a heart pumps blood into the body cavity Closed : heart pumps blood through blood vessels

32. Conduction of Nerve Impulses Animals have nerve cells (neurons) which carry messages which allow for coordination of the body. (senses) Simple animals contain �ganglia� which are a cluster of neurons. Other animals have brains to coordinate all sensory information

33. Support Animals achieve support by the following : Hydrostatic skeleton : consists of water under pressure in a cavity Exoskeleton : rigid external skeleton Endoskeleton : hard material �bone� embedded within an animal

34. Reproductive Strategies Two types of reproduction : Asexual and sexual Asexual : reproduction that doesn�t involve the fusion of two gametes. Sexual : a new individual is formed by the union of gamestes.

35. Reproductive Strategies Some animals are hermaphrodites. This means they have both testes and ovaries, and can produce both types of gametes (sperm and eggs) Ex. : slugs, some fishes, and earthworms

36. Fertilization Animals may have external fertilization or internal fertilization. External : sperm fertilizes the egg outside of the body Internal : sperm and egg union occurs within the females body

37. Ch. 27 Assignment Using the internet and other resources choose 1 animal to research. For your animal explain how they achieve the following six important functions: Digestion, respiration, circulation, conduction of nerve impulses, support, excretion, and reproduction

38. Ch. 27 Review In your journal answer the following questions found on page 612,613. Using Key Terms Understanding Key Ideas #6-#12 Critical Thinking # 17

39. Ch. 27 Journal Summary Your zoology journal should have the following in it: Symmetry Activity(pg.599) Section review Q�s (pg 603) Ch. 27 Activity : animal functions. Ch. 27 Review