Animals

What is an animal? Multicellular, eukaryotic, heterotrophic, non-photosynthetic, without cell walls Either vertebrates or invertebrates Containing specialized cells that have a division of labor in a organism. Animals have specialized cells to enable them to sense and seek out food and mates, and allow them to identify and protect themselves from predators.

Seven Survival Methods Feeding - herbivores, carnivores, parasites, filter feeders, detrivores Respiration-exchange of gases Internal transport - circulatory system; open or closed Excretion - removal of waste Response - use of nerve cells to respond Movement-use of muscles & skeleton Reproduction-sexual or asexual;live young or eggs

Stages of Development Most animals develop from a fertilized egg cell called a zygote. In animals, fertilization may be internal (inside the body) or external (outside the body). After fertilization, the zygote of different animal species all have similar, genetically determined stages of development. Fertilization occurs when a sperm cell penetrates the egg cell, forming a new cell called a zygote. The zygote divides by mitosis and cell division to form two cells in a process called cleavage. Once cell division has begun, the organism is known as an embryo. First layer – blastula, second layer – gastrula Endoderm – inner lining Ectoderm – outer lining Mesoderm – middle lining

What is symmetry? To have a consistent overall pattern of structure. Three types Radial - similar parts that branch out in all directions from a central line Bilateral - two similar halves on either side of a central line Asymmetrical – having no symmetry

What are the body regions? Based on normal orientation of the organism. Anterior - head region Posterior - tail region Dorsal - top or back region Ventral - bottom or stomach region

What is cephalization? Animal Protection & Support The gathering of sensory organs and brain structures in the anterior region. Organisms with cephalization will always have bilateral symmetry. Animal Protection & Support Exoskeleton – hard outer covering made of chitin. Endoskeleton – made of calcium carbonate, cartilage or bone. Invertebrate – animals without backbones but w/exoskeletons Vertebrate – animals with backbones.

Phylum Porifera Sponges Kingdom Animalia Phylum Porifera Sponges

Sponges No mouth, stomach or other organs sessile -(not moving) as adults, mobile -early stage no symmetry smallest - 1 cm long largest - 2 m wide filter feeders reproduce both ways hermaphrodites - containing both sexes

Parts of the sponge Epithelia-like cells – thin and flat responding to touch. Collar cells – lining the interior of the sponge. Each cell has a flagellum used to draw water into sponge. Pore cells – surrounds each pore that allow water to carry food and oxygen into the body. Osculum- large opening where water and waste is pumped out. Spicules - hard particles made of CaCO3 or SiO2 used for support. Amebocytes- b/t the two layers that aid in bringing in food, reproduction and making spicules.

Phylum Cnidaria Hydra, Jellyfish, Coral Kingdom Animalia Phylum Cnidaria Hydra, Jellyfish, Coral

What are the body shapes & parts? Two body shapes polyp - specialized sessile shape medusa - specialized bell shape for swimming Parts epidermis - outer layer mesoglea - middle layer gastrodermis - “stomach skin” inner layer

More Parts Gastrovascular cavity - the “stomach” or hollow gut surrounded by tentacles. The tentacles contain nematocysts which are stinging structures used for defense and capturing food. This group is considered to be carnivores with radial symmetry. Both sexual and asexual reproduction Simple nervous system w/out a brain using a nerve net to conduct impulses.

Classes of Cnidarians Class Hydrozoa – hydras and siphonophores Mostly marine polyp colonies reproduce both ways Hermaphrodites examples include: Obelia, Portuguese man-of-war Photo credited by key-biscayne.com

Eleutheria dichotoma Ectopleura larynx Gonothyraea loveni

Class Scyphozoa Jellyfish Medusa is dominant stage Everywhere in oceans Only class of totally venomous organisms Most are harmless but some can cause death. Examples: Australian box jellyfish, moon jellyfish, Lion mane jellyfish

Body plans of the Scyphozoans

Class Anthozoa Sea anemones & corals. Polyps is the only form and they feed on passing prey. Corals are made of calcium carbonate live in shallow depths make coral reefs. Tropical and Subtropical waters

Class Ctenophora “Comb jellies” Beat cilia to move Secrete sticky mucus to attack prey Most are hermaphroditic Unique feature - bioluminescent All Material Copyright: © Wim van Egmond

Phylum Platyhelminthes Flatworms Kingdom Animalia Phylum Platyhelminthes Flatworms

Flatworm Make-up Simplest animal with bilateral symmetry exhibiting cephalization Range from 1 mm to several meters Found in marine, freshwater & moist land habitats No circulatory or respiratory system One opening for food in and out Contain a gastrovascular cavity Eyespots – used to sense intensity & direction of light Pharynx – used to ingest food Flame cells – collects excess water & removes it Proglottids – body sections: old ones near

Class Turbellaria Mostly free-living marine Move by swimming w/a wave-like motion or a mucus and cilia Feed as scavengers, carnivores Reproduction – sexually as hermaphrodites that fertilize each other internally and asexually through regeneration. Contain eyespots, pharynx, flame cells & simplistic nervous system with ganglia. Most common type is the planarian “cross-eyed”

Marine Flatworms

Pictures of Planarians “Cross-eyed” worm

Class Cestoda Tapeworms – humans house seven different species. Lives in the intestines as parasites Contains a scolex “head” with suckers & hooks for attaching & proglottids which have muscles, nerve cells, & reproductive cells. Each proglottid can contain 100,000 eggs. No eyespots, mouth, gastrovascular cavity, or digestive organs. Almost all are hermaphroditic. Can grow up to 10 m or 33 ft long. Beef, pork and other types.

Beef Tapeworms Life cycle - eggs left behind by infected organism. Ingested by cow(intermediate), cow slaughtered, people eat undercooked meat, eggs hatch and infect human (primary), eggs exit in feces. http://www.merck.com

Class Trematoda Parasitic & hermaphroditic Blood fluke- Schistosoma – causes schistosomiasis. See life cycle on Pg. 710 Brown fluke – N. America causes swimmer’s itch Liver fluke

Phylum Nematoda Roundworms Digestive tract w/two openings Most are separate sexes Protective layer - cuticle Most free-living, some parasitic living in soil, animals, fresh and salt water. Humans play host to 50 types

Types of Roundworms Ascaris - intestines of pigs, horses, humans. Lay about 200,000 eggs Hookworms - burrow into foot through blood to the intestine. 400 million people infected worldwide.

Types of Roundworms Trichinella - causes trichinosis. Humans, pigs, mammals. Eating undercooked pork. Pinworms - most common in US Filarial worms -tropical countries. Causes elephantiasis Pinworm Original image from Oklahoma State University, College of Veterinary Medicine.)

Phylum Rotifera Rotifers transparent, free-living, fresh water uses flame cells bilateral symmetry w/cephalization two eyespots all material © Wim van Egmond