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Kingdom Animalia Defining Characteristic: Multicellular eukaryotic heterotrophs that have tissues made up of specialized cells with no cell walls. All animals carry out 5 essential functions to stay alive 1) Feeding: Need to ingest other organisms / substances for organic supply of molecules. • Herbivores, carnivores, omnivores, detritivores, filter feeding, parasitic, etc. 2) Movement: related to food source or themselves as food sources. • Even sessile animals All animals carry out 5 essential functions to stay alive 3) Respiration = Take in O2 and release CO2 to help break down nutrients from ingestion. 4) Circulation = Transport nutrients, gases, products, and waste products to and from all cells. 5) Excretion = elimination of nitrogenous metabolic waste (ammonia) Animal Evolution Protozoan ancestor: Evidence in the different methods of locomotion (?) Fossil record indicates that, like all kingdoms, animals have been getting more complex over time More complex? The more complex the animal: • The more types of specialized cells and higher degree of internal organization • Greater efficiency in the 5 essential functions Two (non-taxonomical) groups of animals 1. Invertebrates: 95% of all animal species • Do not have backbone • Great diversity; microscopic dust mites to giant squid (20m) 2. Vertebrates: other 5% of animal species. • Includes fishes, amphibians, reptiles, birds, and mammals. Animal Development Developmental stages from zygote to gastrula same for all animals 1) Blastula formation: Zygote divides (how?) until it is a sphere made of a single layer of cells with a fluid filled center. 2) Gastrula formation: Cells on one side of blastula continue to divide and get pushed inward • 3) This will result in two cell layers (germ layers) Mesoderm formation: (most animals) a middle cell layer forms b/w inner and outer cell layers Animal Development Due to multicellularity and gastrulation all animal’s systems develop from these distinct germ (cell) layers 1)Ectoderm: Outer germ layer covering the surface of embryo, gives rise to the outer covering of the animal and, in some phyla the central nervous system. 2)Endoderm: Inner most germ layer that lines the digestive tube, gives rise to digestive tract and organs derived from it (liver & lungs in verts.) 3)Mesoderm: between the ecto and endoderm. Gives rise to muscles, and most other organs The opening to the gastrula can develop into one of two things and is used to classify animals: 1) Protostomes: animals whose mouth develops from gastrula opening. 2) Deuterostomes: animals whose anus develops from gastrula opening. Animal Body Cavities Only animals with mesoderm can be classified as these. Some animals have no body cavity or coelom. Acoelomates Pseudocoelomate: Body cavity is in between endoderm and mesoderm. Coelomate: Body cavity completely surrounded by mesoderm. Importance and advantages of a coelom Provides a space for internal organs to be suspended so that they are not pressed or squished by muscle movements. • Allows for more complex motion. Allow for more specialized body regions to develop, which results in room for organs to grow and expand. • Larger body sizes. Comparing Invertebrates Invertebrate solutions to the 5 essential functions of animals Primitive to complex Feeding and Ingestion Incomplete digestion: digestive tract has one opening that serves as both the mouth and anus. • Cniderians, Platyhelminthes, Echinoderms (convergent) • Incomplete Digestive Systems Mouth/anus Gastrovascular cavity Digestive cavity Cnidarian Pharynx Mouth/anus Flatworm Feeding and Ingestion Complete digestion: digestive tract has two openings which is the beginning and end of digestion. • Nematodes, Annelids, Molluska, Arthropods Complete digestion Intestine Gizzard Crop Pharynx Mouth Annelid Anus Pharynx Crop Anus Arthropod Mouth Stomach and digestive glands Rectum Intestine Respiration Aquatic invertebrates: • Primitive; diffusion of gasses through skin and gastrovascular cavity. • Poriferians, Cniderians, Platyhelminthes, Nematodes, Respiration Aquatic invertebrates: • Complex: external gills • Mollusks, Annelids, Arthropods, Respiration Terrestrial Invertebrates: Need to place organs inside coelom to keep moist • Book lungs (Arachnids, Mollusks) • Trachea (insects) Circulation Primitive invertebrates use diffusion to transport materials (small, thin bodies) Complex / larger have 2 kinds of systems 1.Open circulatory system: – Blood is only partially contained in open blood vessels. – Heart(s) pump blood through coelom which eventually returns – Insects, mollusks Circulation 2. Closed circulatory system: • Blood stays within the entire system (blood vessels and heart) • Materials reach body tissues by diffusing through walls of blood vessels • Characteristic of larger, more active animals. More efficient due to more pressure • Annelids, some mollusks Heartlike structure Small vessels in tissue Blood vessels Annelid: Closed Circulatory System Heart like structures Excretion Get rid of ammonia from protein metabolism, and regulate amount of water in body. Diffusion (poriferians, Cniderians) Flame cells (flatworms) Nephridia (annelids, and mollusks) Malpighian tubules (arthropods) Flame Cells Excretory tubules Flame Cell Flatworm Excretory tubule Movement and Support Animals have tissues called muscles that contract and relax in order to move the animal. These muscles need to work together with some sort of skeletal system 3 types Movement and Support 1) Hydrostatic Skeletons: (cniderians, annelids) muscles surround a fluid-filled body cavity that supports the muscles. • When the muscles contract, they push against fluid in the body cavity, causing the body to change shape. Movement and Support 2) Exoskeletons: an external skeleton made of chiten or calcium carbonate. • Muscles on the inside • Arthropods and mollusks Movement and Support 3) Endoskeletons: Skeleton inside of body cavity. • Muscles on the outside of skeleton • Echinoderms, chordates