Zoology

1. Zoology Test #1 Material

2. What is an animal? • Mutlicellular, heterotrophic (get their own food), eukaryotes • Cells do not have cell walls • Have nervous and muscle tissues • Usually reproduce sexually These are characteristics of MOST animals.

3. Reproduction • Sperm + Egg => • Zygote (fertilized egg) => • 8 cell ball (cleavage)=> • Blastula (hollow ball of cells) => • Gastrula

4. Evolution of Animals • Most scientists agree that the animal kingdom is: • Monophyletic- came from a common ancestor • Has branches where each adaptation comes in

6. Parazoa “beside the animals” • Has no true tissues • Sponges

8. Eumetazoa • 2 branches based on symmetry • Radial • ex.) jellyfish and relatives • has a top and a bottom • no head or rear • no left or right • Bilateral • Ex.) all other animals • Has a top and bottom • Has a head and a tail • Has left and right sides

9. Acoelomates • Evolution of body cavities • More complex animals  • Started without body cavities • Ex. Flatworm 

10. Acoelomates Continued • Then the insides were suspended in a fluid filled region and could move around without disturbing each other. • Ex. Roundworms

11. Protostomes and Deuterostomes • During the gastrula phase the hollow ball developed a tube in the middle. • In protostomes, the first opening becomes the mouth (clams, snails, squids, worms, crustaceans, insects, and spiders)

12. Protostomes and Deuterostomes Continued • In deuterostomes, the first opening becomes the anus (sea stars, sea urchins, and vertebrates)

14. How Classification Began • Classification – grouping of objects or information based on similarities • Taxonomy – branch of biology for grouping and naming organisms • Taxonomists – a biologists who studies taxonomy • Aristotle • Developed the first method of classification • Grouped them into 2 groups: plants and animals • His system was useful but did not group organisms according to their evolutionary history

15. Classification Continued • Linnaeus • Developed method we still use today • Based on structural and physical similarities of organisms • Binomial nomenclature - gives each organism 2 names. • The proper way to write a scientific name • Example: animalia, vertebrata, mammalia, primata, hominidae, Homo sapien • All letters are lower case except the genus is capitalized. • Genus and species are underlined

16. Animal classification • Kingdom Largest • Phylum • Class • Order • Family • Genus • Species Smallest • These groups are called taxa. •   Kings play chess on flat green stools.

17. Scientific Names • Scientific Names are written in Latin because: • the language is no longer used • the words stay the same and cannot change since the language is dead • the words only have one meaning • Common names are misleading because any organism can have multiple common names

18. Dichotomous Key • A set of paired statements used to help identify organisms • Read each statement and decide which fits your organism • Go to where that statement tells you and read the next two statements • Eventually you will reach a statement that tells you the name of the organism

19. Phylogenetic Classification Models • Species that share a common ancestor also share an evolutionary history • Phylogeny – the evolutionary history of a species • Phylogenetic classification reveals the evolutionary relationships of species • Cladistics • System of classification that is based on phylogeny • As groups of organisms diverge and evolve from a common ancestral group, they retain some unique inherited traits. • Cladogram • Branching diagram identifying a group’s derived traits. • Similar to a pedigree or family tree. • Two groups on diverging branches probably share a more recent ancestor than those groups farther away.

21. Invertebrates

22. Phylum: Porifera (sponges) • Classes: 4 • Orders: 18 • Families: 80 • Species: about 10,000 • No tissues because cells are not specialized • No nerves or muscles, but cells can sense and react to changes in the environment • Of 10,000 species, 100 of those are in freshwater

23. Porifera Sack of cells with pores Top opening is called the osculum-where water exits out of the sponge Water goes in through the pores called the spongocoel Under certain conditions, the cells contract and close all of the openings Filter feeders

24. Porifera Reproduction • Asexual Reproduction: • Budding • Can regenerate lost parts • Can reproduce asexually from a broken piece of the parent • Sexual Reproduction • Hermaphrodites (have both male and female parts) • Produces both sperm and egg • Sperm shoots out into the water and is then taken back in (some sponges that are around cross are fertilized)

26. Phylum:Cnidaria(hydras, jellies, sea anemonies, and coral) • Classes:4 • Orders:27 • Families: 236 • Species: 8,000-9,000 • Have a single opening that is both the mouth and anus • Sack with one digestive compartment

28. 2 Forms of Cnidarians • Polyp (hydras and sea anemones) • Tentacles push food into the mouth  • Medusa (Jellies) • Tentacles have NEMATOCYSTS – stinging cells that grab and immobilize prey using toxins.

29. Cnidarian Reproduction Asexually – budding (polyp form) Sexually –have separate male and female medusae that produce gametes that join through external fertilization

31. Phylum: Platyhelmenthes (Flukes and Tapeworms) • Classes: 4 • Orders: 35 • Families: 360 • Species: 17,500 • flatworms • Some are microscopic and can grow to be up to 20 m long. • Still only have one opening and one digestive cavity • Absorb nutrients across their body surface

32. Flukes • Live as parasites in or on other animals • Attach with suckers to internal organs or to the outer surface

33. Tapeworms Also Parasites in or on other animals Head has suckers and hooks that lock into intestines Absorbs food digested by Humans Absorbs nutrients from digested food Eggs leave host in the feces

35. Transmission • This is why you shouldn’t drink contaminated water • Some cows have the eggs in their muscles • When we eat under cooked meat, you have a chance of contracting worms • Can be 20m in length and can block intestines

36. Flatworm Reproduction Sexually - Hermaphrodites – internal fertilzation. Asexually – fission – when damaged, regenerates new body parts.

37. Phylum: Nematoda( pinworms & hook worms) • Classes: 4 • Orders: 25 • Families: 185 • Species: 20,000 • Humans host about 50 species • Also attacks animals and plant roots • One species is called Trichinellaspiralis • causes trichinosis • Caused by eating undercooked infected pork or other infected meat • They can go into human muscles or other organs.

38. Roundworm Feeding Have a simple digestive system. Have a mouth and an anus Parasitic roundworms use specialized structures (usually with hooks) to attach to a host.

39. An Important Group Many nasty parasitic infections in humans, livestock

40. Hookworm

41. Hookworm

42. 1,200 species Probiscis worms or ribbon worms Can be marine, freshwater, or live in damp soil Size ranges from .5cm to over 50m Sexual and asexual reproduction Have a complete digestive tract & a closed circulatory system. Blood is enclosed in vessels Have no heart, but blood is propelled by muscles squeezing the vessels Phylum: Nemertea

44. Classes: 3 Orders: 31 Families: 130 Species: 12,000 Segmented worms (Annelida means “little rings”) From 1mm to 3 m > giant Australian earthworm Phylum: Annelida

45. Earthworm Divided by septa Digestive tract, blood vessels, and nerve cords penetrate septa and run the length of the body Class: Oligochaeta

46. Hermaphrodites, but they cross fertilize 2 earthworms align and exchange sperm then they separate They store the sperm while an organ produces a mucous cocoon. The cocoon then slides along the worm and picks up the eggs, then the sperm The cocoon slips off the head and stays in the soil until it hatches Oligochaeta Reproduction

47. They can also reproduce asexually by breaking apart They eat their way through the soil and absorb nutrients through the soil Oligochaeta Reproduction

48. Leeches Most live in fresh water, but some can live in moist vegetation Some feed on other invertebrates, but some are blood sucking parasites that feed by attaching to the host. Most abundant in the tropics. From 1-30cm long Hermaprodites but can cross fertilize Copulation is similar to the earthworm, by making cocoons and buries them in the dirt Class: Hirudinea

49. Some use blade like jaws to slit the skin of the host while others use an enzyme to digest a hole in the skin Host is usually unaware because the leech secretes an anesthetic Also secretes an enzyme (hirudin) that keeps the host’s blood from coagulating It then usually sucks as much blood as it can usually 10X it’s weight can usually last a month without another meal Feeding