Chapter 24 Introduction to Animals

Transcription

1 1 Chapter 24 Introduction to Animals I. Animal characteristics A. General Animal Features Multicellular B. Feeding and Digestion a. acquire nutrients from various sources obtaining nutrients unique to the animal a. intracellular digestion-inside of the cells ex. most digest their food in internal body cavities or organs C. Support Invertebrates a percent of all animals outside framework to protect organs support muscles Molt-shedding of old skeleton and replaced with larger skeleton refer to grasshopper notes internal framework ex. sea urchins, starfish a. animals with backbones backbones grow with animal backbones made of either calcium or cartilage support body protect organs D. Animals live in many habitats due to the variety of adaptations for feeding, digestion and support Land and aquatic biomes E. NO CELL WALLS!! All animals have cell tissues except sponges a. Tissues are a group of cells that are specialized to perform a specific function.

2 2 F. G. Examples of tissues in man muscle tissue epithelial tissue The evolution of nerve and muscle tissue allowed animals to become more complex and move quickly. The ability to move is important to the animal kingdom. Some animals are sessile/stationary as an adult but move during some stage of their development. a. ex. jellyfish ex. ex. sponge Sexual reproduction (male/female) a. most common defined-when sperm and egg meet to form a zygote (fertilized egg) External fertilization sperm and egg meet OUTSIDE of the body requires water (aquatic environment) ex.frog, fish, jellyfish, sponge sperm and egg meet INSIDE the body of the female a. budding fragmentation parthenogenesis ( eggs develop with no male) a. Mitosis (cell zygote now called an embryo) forms a solid ball of cells continues to divide to form a fluid-filled ball of cells continues to grow until the cells start to push inward forming a Gastrula-cells move inward in the blastula and forms a bubble inside a bubble the cells which do not continue to develop form the yolk sac to feed the developing organism 4. a. -inner layer of cells in the gastrula becomes the digestive tract Ectoderm-outer layer of cells in the gastrula becomes the nervous tissue and skin

3 3 II. -middle layer of cells which grow between the endoderm and ectoderm in more advanced animals. becomes muscle, circulatory, respiratory and excretory systems. A. Evolution of Animal Body plans Animals without tissues-simplest Animals without segments B. Development of Tissues First branch on the evolutionary tree sponge has no tissue tissue development brought Phylum Cnidaria (jellyfish, coral, hydra) C. Symmetry-describes the similarity or balance among body structures of organisms a. irregular shape NO symmetry or order one cell layer a. organism can be divided along any plane (through the center) and have equal halves. ex. jellyfish, starfish BILATERAL SYMMETRY a. animal can be divided into mirror image halves along only one plane (cut). ex. dog, cat, fox, ant, you et three cell layers (ectoderm, mesoderm and endoderm) head region Anterior = head (nerve tissue) Dorsal-backside Ventral-underside or belly Remember V-neck sweater! Most animals move with their anterior portion moving first through the environment to be able to react quickly. D. COELOMATES a. animal with a fluid-filled body cavity (coelom) YOU, mammals, reptiles, et Key adaptation in the evolution of larger and more specialized body structures. e. animal could become larger and more active (high survival advantage) f. most advanced animal

4 4 III. a. Cavity (coelom) only partially lined with mesoderm limits tissue, organ and system development ex. roundworm a. NO body cavity simplest animals with solid bodies without a body cavity. nutrients and wastes diffuse from one cell to another e. ex. flatworms, planaria E. Development in Coelomate Animals (patterns of embryologic development) a. Mouth develops from the first opening of the gastrula ex. Mollusks (clam, snail, slug, squid, and octopus) Annelids (segmented worms) and Arthropods (segmented body) a. Anus develops from the first opening of the gastrula ex. Echinoderms (starfish) and Chordates (you) F. Segmentation important feature in evolution a. animal can be put together from many similar parts animals can survive damage to one segment because other segments may carry the same function. movement is more effective because segments can move independently. A. Phylum Porifera (sponges) 5,000 to 10,000 species Traits a. asymmetrical a. 2 layers of cells outside epithelial tissue to protect inside collar cells with flagella for water movement Osculum-Mouthlike opening at the top of the sponge a. Filter feeder 5 inch sponge can filter close to 25 gallons of water a day. sessile Digestion takes place inside of each cell with the help of dissolved oxygen. 4. a. Jelly-like material between cell layers. help with digestion, excretion, and making gametes

5 5 helps to secrete stronger material for support (spicules) small needlelike structures made of calcium carbonate, silica (sand) and tough fibrous protein called spongin. helps to keep animals from eating them. 5. Sponge diversity Different species have different kinds of spicules 6. a. no nervous system can detect touch or chemical signals which control their pores. (special cells) 7. a. Asexual fragmentation (piece of sponge breaks off of parent) budding (bud forms and drops off to settle at the bottom.) -special cells formed during adverse conditions Sexual most common form of reproduction in sponges eggs stay in the sponge..sperm released into the water collar cells draw sperm into the sponge to the egg. larva hatch and are free-swimming and has flagella. Offspring must move away from parent so that they do not compete for space or nutrients. larva eventually attach to a surface and develop into anadult sponge 8. a. Food for some fish and turtles worms some fish algae some camouflage for mollusks cleaning chemicals discourage and/or prevent infection studying to see if they could be used as an antibiotic, anti-inflammatory, or antitumor medication B. Phylum Cnidaria (coral, jellyfish ) a. One body opening Radial symmetry slow moving or sessile allows animals to detect and capture prey from any direction.

6 e. aquatic environments Feeding and digestion a. -stinging cells in the tentacles. works like a powerful harpoon tentacles under high osmotic (water) pressure touch and chemical stimulus causes the release of the stinging cells. forceful enough to penetrate a fastest cellular processes in nature (impossible to escape) after prey is paralyzed, the tentacles bring it into their mouth Inside the Cnidarian the gastrovascular cavity releases digestive enzymes to breakdown tissue. Evolutionary advancement Undigested material is ejected from the mouth a. Nerve net conducts stimuli to all parts of the body. muscle-like cells cause movement NO blood vessels, respiratory systems or excretory organs. 4. a. Hydroids form colonies many are POLYPS-tentacles face upward hydra Transparent and float on the water surface MEDUSA-tentacles face downward Polyps present in the larva stage. Polyp stage dominant Sea anemone live as individual animals Corals live in colonies and secrete calcium carbonate shelters around their soft bodies. extend their tentacles to feed Symbiotic relationship with algae. Algae give oxygen and food to coral. Coral use CO2 and wastes used by the corals. Health of coral depends on water temperature, adequate light and appropriate water depth. (climate change affecting the health of the coral) 5. a. Mutualism (coral/algae sea anemone/hermit crab sea slug/sea anemone.. Man some stony coral used in surgical procedures (mimics bone) face, arm and legs 6