Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Emotion in animals wikipedia , lookup
History of zoology since 1859 wikipedia , lookup
Deception in animals wikipedia , lookup
History of zoology (through 1859) wikipedia , lookup
Zoopharmacognosy wikipedia , lookup
Animal cognition wikipedia , lookup
Animal communication wikipedia , lookup
Animal locomotion wikipedia , lookup
Sponges and Cnidarians 1 I. Introduction to the Animal Kindgom A. What is an animal? 1. Animals are heterotrophic (feed on organic compounds) 2. Multicellular 3. No cell wall 2 4. The bodies of most animals contain tissues. 5. Animals have epithelial, muscular, connective and nervous tissue. 6. Over 95% of all animal species are grouped into a group called the invertebrates (animals without a back bone) 3 7. The other 5% contains animals in the vertebrate groups (animals with a back bone) 4 B. What animals do to survive 1. Animals carry out the following essential functions: feeding, respiration, circulation, excretion, response, movement and reproduction. 5 6 C. Trends in Animal Evolution 1. The animal kingdom starts with simple animals and goes to complex animals. 2. Animal cells have evolved to carry out different functions, such as movement and response. 7 3. Animals that reproduce sexually begin life as a zygote or a fertilized egg. 4. The zygote undergoes a series of divisions to form a blastula-which is a hollow ball of cells. 5. A protostome is an animal whose mouth is formed from the blastopore. 8 6. A deuterostome is an animal whose anus is formed from the blastopore. 7. The anus is the opening through which waste leaves. 9 8. During early development, the cells of most animal embryos differentiate into three layers. 9. Endoderm (inner most), mesoderm (middle) and ectoderm (outer) 10 D. Body Symmetry 1. Body symmetry is the way a body can be divided. See page 662. 11 2. Radial symmetry is a body part that repeats around the center of the body. Example: sea anemone 12 3. Animals with bilateral symmetry can be divided into right and left sides. 13 Asymmetry 14 E. Cephalization 1. Cephalization is the concentration of sense organs and nerve cells at the front end of the body. 2. Most animals have a body cavity, which is a fluid filled space that lies between the digestive tract and the body wall. 15 II. Sponges A. What is a sponge? 1. Sponges area classified, as animals because they are multicellular, heterotrophic, have no cell wall and contains a few secularized cells. 2. Because sponges are so different than other animals, scientists think they evolved independently from all other animals. 16 17 18 B. Form and function in sponges 1. Sponges have nothing resembling a mouth or gut, and they have no tissue or organ systems. 2. Sponges are asymmetrical; they have no front or back ends, and no left or right sides. 19 3. Chanocytes are specialized cells that use flagella to move a steady current of water through the sponge. 20 4. Water leaves through the large opening called the osculum. 21 5. The movement of water through the sponge provides a simple mechanism for feeding, respiration, circulation and excretion. 6. Sponges have a simple skeleton. 7. In harder sponges, the skeleton is made of spiny spicules 22 8. Spicules are made by archaeocytes, which are specialized cells that move around within the walls of the sponge. 9. Softer sponges have an internal skeleton made of spongin. 10. Sponges are filter feeders. 23 11. Digestion takes place inside of the cells. 12. Sponges rely on the movement of water through their bodies to carry out body functions. 13. Sponges do not have nervous systems that would allow them to respond to changes in their environment. 24 14. Sponges can reproduce either sexually or asexually. 15. In most sponges they contain BOTH egg and sperm. It usually produces it at different times. 16. In sponges the sponge will release its sperm and then it will float to another sponge. 25 17. In sponges fertilization occurs inside the sponge, called internal fertilization. 18. After fertilization they zygote develops into a larvae. 19. A larvae is an adult form. 26 20 The larvae of sponges are motile and are usually carried by currents before they settle on the sea floor. 21. Sponges can reproduce asexually by budding or by producing gemmules. 22. Gemmules are groups of achaeocytes surrounded by a tough layer of spicules. 27 C. Ecology of sponges 1. Sponges are important in aquatic ecology. 2. They provide habitats for other marine animals. 3. There are some that are photosynthetic therefore they produce oxygen for other organisms. 4. Sponges are filter feeders so they clean up the water. 28 29 III. Cnidarians A. What is a cnidarinan? 1. Cnidarians are soft bodied, carnivorous animals that have stinging tentacles arranged in circles around their mouth. 2. They are the simplest animals to have body symmetry and specialized tissues. 30 31 3. Cnidarians get their name from their cnidocytes (stinging cells.) they are located on their tentacles. 32 B. Form and Function in Cnidarians 1. Cnidarians are only a few cells thick and have simple body systems. 2. Cnidarians typically have a life cycle that includes two different looking stages. 33 3. Polyp and a medusa see page 670. 4. A polyp is slim with arm like tentacles. The mouth points upward. Polyps are usually sessile. 5. A medusa has a motile, bell-shaped body with the mouth on the bottom. 34 Polyp 35 Medusa 36 C. Feeding 1. After paralyzing its prey, a cnidarians pulls the prey through its mouth and into its gastrovascular cavity- a digestive chamber with one opening. 2. Food enters and a waste leaves the body through that opening. 37 38 39 D. Respiration, circulation and excretion 1. After digestion, the nutrients are usually transported throughout the body by diffusion. 2. Cnidarians respire and eliminate wastes through their body wall by diffusion. 40 E. Response 1. Cnidarians gather information from their environment using specialized sensory cells. 2. Both polyps and medusas have a nerve net. A nerve net is a loosely organized network of nerve cells that together allow cnidarians to detect stimuli. 41 F. Movement 1. Different cnidarians move in different ways. 2. An anemone moves by hydrostatic skeleton. 42 G. Reproduction 1. Most cnidarians reproduce both sexually and asexually. 2. Polyps can reproduce asexually by budding. 3. In most cnidarians, sexual reproduction takes place with external fertilization in the water. 43 44 4. External fertilization takes place outside the female’s body. 5. The sexes are often separate (either male or female) 6. The female releases eggs and the male releases sperm. 45 7. They float until they are fertilized into a zygote and then a swimming larva and finally back to a polyp. See page 672. 46 H. Groups of cnidarians 1. Cnidarians include jellyfishes, hydras and their relatives and sea anemones and corals. 47 2. The class Scyphozoa contains the jellyfish. 3. They live their lives primarily in the medusa stage. 48 4. The class Hydrozoa is mainly polyps. 5. They grow into a branching colony. 49 6. The class Anthozoa contains sea anemones and corals 50 7. Sea anemones are solitary polyps that live at all depths of the ocean. 51 8. Most corals live as a colony. 9. Hard coral colonies are usually founded when a motile larva settles onto a hard surface and develops into polyp 52 I. Ecology of corals 1. The worldwide distribution of corals is determined by a few variables: temperature, water depth and light intensity. 2. Many coral reefs are suffering from human activities. 3. Coral bleaching has become common. 53 54 4. High temperatures can kill the algae that usually live in the tissues of corals, leaving behind white skeletons. 55 THE END 56