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The Animal Kingdom . Preparation for Dissection. Animals have:. Multicellular organisms Eukaryotes have a nucleus and has other organelles No cell walls. Invertebrates. Invertebrates are animals that do not have a backbone. 95% of animals are invertebrates 11 of 12 phylum of animals.
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The Animal Kingdom Preparation for Dissection
Animals have: Multicellular organisms Eukaryotes have a nucleus and has other organelles No cell walls
Invertebrates Invertebrates are animals that do not have a backbone. 95% of animals are invertebrates 11 of 12 phylum of animals
Symmetry Radial: Similar parts branch out in all directions from central line (example: starfish) Bilateral: 2 similar halves on each side of central plane (example: earthworm)
Invertebrates With no backbone, animals need various methods of support for body Can have exoskeleton-hard covering on outside (exo-)
Starfish (Sea Stars) An invertebrate Are carnivores (eat animals such as clams) Suckers grab onto food and mouth balloons out to pull food in.
Starfish Continued Have the ability to regenerate arms that they have lost. Move by “walking” along the bottom of the seafloor with their tube feet. Video http://www.schooltube.com/video/46aadd3ebaeb38f2b44b/ lhttp://www.arkive.org/common-starfish/asterias-rubens/image-A8127.html
Terminology for Dissections: Anterior: Front end of a bilateral organism Posterior: Back end of a bilateral organism Dorsal: The top of a bilateral organism Ventral: The bottom of a bilateral organism
Phylum: Chordata Have a dorsal nerve cord Have notochord, rod of tissue on dorsal side of body Subphylum: Vertebrates Dorsal nerve cord develops into brain and spinal cord Notochord only during embryonic stage, replaced by backbone
Characteristics of Vertebrates Have endoskeleton: internal skeleton to support large, heavy body. Grows as animal grows Segmented: see in ribs and vertebrae Skin adapted to hold water in body (except fish) Use lungs or gills for gas exchange
Fish Classification Ectothermic: body temperature is same as environment (“cold-blooded”) Evolved 550 million years ago
Class Reptilia Evolved about 300 million years ago, after amphibians went onto land First fully terrestrial organisms, don’t go into water to reproduce
Class Reptilia Have thick, dry, scaly skin to keep water tight Ectothermic: warms body by absorbing heat from environment
Reproduction in Reptiles Oviparity: fertilized egg enclosed in tough protective shell, deposits into safe place in environment- BIG EVOLUTIONARY STEP –No longer needed water to reproduce Nutrition comes from yolk of egg Most reptiles, birds, a few mammals
Groups of reptiles Reptile classification: 1. Turtles and tortoises 2. Crocodiles 3. Lizards and snakes 4. Tuataras (only 2 living species remain)
Class: Aves (Birds) Largest class of terrestrial vertebrates Evolved around 150 million years ago Bodies of birds are well adapted to flight
Characteristics of Birds 1. Feathers: for flight and insulation 2. Wings: forelimbs modified into wings for flight 3. Lightweight, rigid skeleton: bones thin walled and hollow 4. Endothermic: maintain own body temperature
More….. 5. Respiratory system: need oxygen in lungs, connected to several air sacs 6. Beak: no teeth 7. Lay eggs in hard shell and kept warm by one or both parents
Evolution of Birds Birds evolved at the end of the Jurassic period (150 million years ago) Thought to have evolved from dinosaurs that were small and fast First bird species (Archaeopteryx)
Class: Mammalia First ancestors first appeared 300 million years ago First mammals appeared at same time as first dinosaurs Dinosaurs kept mammals small for survival until their extinction
Characteristics of Mammals 1. Endothermic: control own body temp 2. Hair: Insulate body to prevent heat loss 3. Divided heart: More efficient at keeping high levels of oxygen in blood 4. Milk: Females produce milk to feed young (mammary glands)
Mammals Continued 5. Single jawbone: helpful to identify mammal fossils 6. Specialized teeth: at front to bite, cut, and capture prey. In back to grind and chew
3 Main groups of mammals: Monotremes: Are oviparious (lay eggs) 3 species exist Platypus, 2 species of anteaters Most primitive of all mammals
Marsupials: Result of isolation, Australia and New Guinea Are viviparious Time embryo in mother is very short
3. Placental mammals: Viviparious Long period of development inside mother Nourished by placenta 18 orders
Some Examples Examples of placental mammals: Bats: use echolocation to navigate (have small eyes and large ears) Order cetacea (whales, porpoises, dolphins)