Chapter 7

1. Chapter 7

2. Section 1 • What is an Animal?

3. Structure of Animals • Animals are composed of many cells. • Cell is the basic unit of structure and function of in living things. • Cell are organized into higher levels of structure. • Systems • Organs • Tissue

4. Structure of Animals • Group of similar cells and specific function is called a tissue • Tissues can combine together to for an organ, which is several different tissues. • Ex. Stomach, made of muscle, nerve and other tissues. • The stomach is then apart of the digestive system.

5. Functions of Animals • The major function of animals is to obtain food and oxygen, keep internal conditions stable, move, and reproduce. • Adaptations are structures or behaviors to perform basic functions in their environment. • Animals must eat other organisms to live • Animals are always on the move for food and oxygen

6. Functions of Animals • Animals must maintain stable cond. Otherwise animal can’t survive. • Animals are always moving. • Ex. Dogs, cats, fish, etc… • Some animals only move in early stage of life • Ex. Barnacle • Most animals reproduce sexually • Sexual reproduction is the process that a new org. develops from the joining of an egg and sperm cell.

7. Functions of Animals • Asexual reproduction is where a single organism make a new organism identical to

8. Classification of Animals • Biologists have already found and named 1.5 million animal species • An animal is classified based on its looks, how it develops and the contents of its DNA. • Classification reveals its relationship to other animals. • There are 35 groups of animals put into different groups called phylum

9. Classification of Animals • Vertebrates are animals with a backbone. • Invertebrates are animals without a backbone. • 97% of all animals are invertebrates

10. Section 2 • Animal Symmetry

11. The Mathematics of Symmetry • The balanced arrangement of parts in an animal and other objects is called symmetry • Bilateral symmetry is one line dividing an object into equal halves. • Radial symmetry is many lines thru a central point. • Can infer some char. of animals based on their symmetry.

12. Symmetry and Daily Life • Animals with radial symmetry are like the spokes of a bike wheel • Most animals have bilateral symmetry • Animals with bilateral symmetry are more complex and larger

14. Section 3 • Sponges, Cnidarians, Worms and Mollusks

15. Sponges • Sponges are invertebrates are animals usually without symmetry and have no tissues or organs. • Looks like a hollow bag with a large opening at one end. • Belongs to the phlyaPorifera, meaning to have pores. • Sponge attaches itself to hard surfaces underwater

16. Sponges • Water carries food and oxygen to the sponge • Water also helps sponges to reproduce • Sponges can reproduce both sexually and asexually • In asexual reproduction, a new “bud” grows out of the adult sponges side • Bud eventually breaks free and grows up to be an adult

17. Sponges • Sponges are both boy and girl • Sponges will produce both sperm and egg cells • Sperm is released from one sponge and enters another sponge to fertilize with an egg • A larva will form and then grow on its own • Larva is an immature form of an animal that looks very different from an adult

19. Cnidarians • Cnidarians are invertebrate animals that use stinging cells to capture food and defend themselves • Ex. Jellyfish, coral, and sea anemones • Have 2 different body plans • Medusa is bowl shaped and is adapted for swimming life. • Polyp is vase shaped with a mouth at the top

20. Cnidarians • Cnidarians stinging cells are key to obtaining food. • Cnidarians also can reproduce sexually and asexually • Budding is the most common type of asexual reproduction • Sexual reproduction can occur in many ways • Some have both sexes, some have separate sexes and many have life cycles

22. Worms • Biologists classify worms into 3 major phyla • Flatworms, roundworms, and segmented worms. • Flatworms belong to the phylum Platyhelminthes • Roundworms belong to the phylum belong to the phylum Nematoda • Segmented worms belong to the phylum Annelida

23. Worms • All worms are invertebrates with long narrow bodies • Worms are the simplest organisms with a brain found in the head end • Worms are able to reproduce both sexually and asexually

24. Worms • Flatworms • Ex. Tapeworms, planarians, and flukes • Flatworms are flat and soft, like jelly • Flatworms are a parasite • Parasites are organisms that live in or on another organism • A parasite takes food from its host • A host is the organism that the parasite uses as a home

25. Worms • Roundworms • Roundworms have cylindrical bodies • Roundworms have a digestive system that is open at both ends • This allows digestion to happen in orderly steps • Allows for more absorption of food nutrients. • Segmented worms • Ex. Earthworms, leeches, and some sea-floor worms

26. Worms • Segmented worms • Segmented worms have bodies made up of many linked sections. • On the outside the segments all look alike. • Segmented worms have a closed circulatory system

28. Mollusks • Snails, slugs and octopuses are all invertebrates • Mollusks have soft, unsegmented bodies often covered by sells and a thin layer of tissue called a mantle • The mantle covers the internal organs, and an organ is called a foot • Foot is usually adapted for different functions

29. Mollusks • Mollusks have bilateral symmetry • Mollusks are classified into 3 major groups • Gastropods (Snails and Slugs) • Bivalves (Clams and Oysters) • Cephalopods (Octopuses and Squids) • Gastropods are the largest group of mollusks • Gastropods are mollusks that have a single external shell or no shell at all

30. Mollusks • Gastropods feed using a radula, a flexible ribbon of tiny teeth • Some gastropods are herbivores, animals that eat plants. • Bivalves are found in all kinds of watery environments • Bivalves are mollusks that have 2 shells held together by hinges and strong muscles

31. Mollusks • Cephalopods are the only mollusks with a closed circulatory system • A cephalopod is an ocean dwelling mollusk whose foot is adapted to form tentacles around its mouth. • Cephalopods swim by jet propulsion • They squeeze out a current of water out of the space surrounded by the mantle.

32. Section 4 • Arthropods and Echinoderms

33. Characteristics of Arthropods • Arthropods are invertebrates that have an external skeleton , a segmented body, and jointed attachments called appendages. • Ex. Ants, Grasshoppers, Lobsters, Spiders. • Arthropods have bilateral symmetry, an open circulatory system, and a digestive system with 2 openings. • Most arthropods reproduce sexually

34. Arthropods • Scientists have identified more than 1 million species of arthropods • More than all other species combined • As arthropods grow larger, their waxy exoskeleton can’t expand • Exoskeleton is like a suit of armor • The process of shedding the exoskeleton is called molting • After molting, exoskeleton is soft for a short time

35. Arthropods • Arthropods have segmented bodies • Many arthropods also have jointed appendages attached to their bodies • Fingers to your hands • Arthropods have specialized appendages • For walking, obtaining food, reproducing, and sensing the environment.

36. Insects • The major groups of arthropods are Insects, Crustaceans, Centipedes, and Millipedes. • Insects are arthropods with 3 body sections, 3 pairs of legs, 1 pair of antennae, and usually 1 or 2 pairs of wings. • The 3 body sections are the head, thorax and abdomen

37. Insects • The process in which an animals body goes thru a dramatic change in its form during its life cycle is called a metamorphosis • Egg, larva, pupa, adult

38. Crustaceans • Crustaceans are arthropods with 2 or 3 body sections, 5 or more pairs of legs and 2 pairs of antennae • Ex. Shrimp, crab, crayfish and lobsters • Crustaceans obtain food in many ways • Many are scavengers • Some are predators • Most crustaceans begin life microscopic • Go thru partial metamorphosis, larva into adults

39. Arachnids • Arachnids are arthropods with 2 body sections, 4 pairs of legs, and no antennae • Ex: Spiders, mites, ticks and scorpions • 2 body sections are a head/midsection and the abdomen • All spiders are predators • Spiders have hollow fangs that inject venom • Venom turns insect tissue to mush

40. Arachnids • Fangs are then used like drinking straws • Almost all spiders are harmless • Brown recluse and black widow require hospital • Ticks are parasites that live on the outside of the host animal • Nearly every type of land animal has a tick that sucks its blood

41. Arachnids • Scorpions live mostly in hot climates • Mostly active at night • During the day they hide in cool places • At the end of its abdomen is a spinelike stinger • Stinger is used to inject venom into its prey • Usually a spider or insect

42. Centipedes and Millipedes • Easy to count the legs on other Arthropods • Not easy for centipedes or millipedes • Both have 2 body sections and numerous pairs of legs • Head section has 1 pair of antennae • Abdomen section with many segments • Centipedes are swift predators

43. Centipedes and Millipedes • Inject venom with pair of claws near mouth • Millipedes have more than 80 segments and each segment has 2 pairs of legs • Most millipedes are scavengers • Millipedes curl up into a ball when in danger • Some also squirt an awful smelling liquid at a potential predator

44. Echinoderms • Echinoderms are in the phylum Echinodermata • Echinoderms are invertebrates with an internal skeleton and a system of fluid filled called a vascular system • All echinoderms live in salt water • The skin of most echinoderms is supported by an internal skeleton called an endoskeleton

45. Echinoderms • Adult echinoderms have a unique radical symmetry in which body parts come in multiples of 5’s and look like tire spokes • Echinoderms have tube feet that are sticky and act like suction cups • By forcing water, contracting the feet • Most are either male or female

46. Echinoderms • Female releases her eggs into the water, male fertilizes with his sperm • Eggs develop into swimming larvae, undergo metamorphosis into adults • Share internal structures, do not look alike on the outside • Different ways of feeding and moving • Major groups are the Sea Stars, Brittle Stars, Sea Urchins, and Sea Cucumbers.

47. Section 5 • Fishes, Amphibians, and Reptiles

48. Characteristics of Chordates • Members of the phylum Chordata are called chordates • At some point in its life, a chordate with have a notochord, a nerve that runs down its back, and a slit in its throat area. • Ex: Fish, Amphibians, Reptiles, Birds, and Mammals • Chordates get their name from the notochord

49. Characteristics of Chordates • The notochord connects the brain and nerves • Chordates have slits in their throat area called gill slits • Invertebrate and some vertebrate chordates keep their gill slits all their life • In other vertebrates, gill slits disappear before birth

50. Characteristics of Vertebrates • Most chordates are vertebrates • A vertebrate has a backbone that is part of an internal skeletal system • The backbone is formed by many bones called vertebrae • Each vertebrae has a hole in it to allow the spinal cord to pass thru it • The backbone protects the body, gives it shape, and gives muscle a place to attach