Introduction to Animals Characteristics of animal
General features of animals All animals share the following eight characteristics: Heterotrophy Sexual reproduction Mobility Blastula Formation Multicellularity Absence of cell wall Diploidy Cells organized into tissue
Features of animals Heterotroph-unable to make their own food. Mobility-Ability to move from place to place using muscle cells 1. list the five types of movements)
Features of animals Multicellularity-more than one cell Diploidy-possess two copies of each chromosome, one from each parent. Please note: that gametes are haploid 2. How many pairs of chromosomes do humans have?)
Features of animals
Sexual reproduction-the fusing of the male and female gamete to form an offspring Absence of a cell wall-Lacks a rigid outer wall, this allows cells mobility 3. What is the male gamete called?
Features of animals Plant cellAnimal cell
Features of animals Blastula formation-the formation of a hollow ball of cells as a fertilized egg undergoes cell division Cells of the blastula develop into three primary tissue layers-ectoderm, endoderm, mesoderm 4. What is the scientific name for a fertilized egg? 5. Why are called primary tissue layers?
Features of animals
Features of animals Ectoderm-outer layer of skin, nervous system, sense organs Endoderm-lining of the digestive system, respiratory system, urinary bladder, liver and many glands Mesoderm-most of the skeleton, muscles, reproductive and excretory organs
Features of animals Note: Sponges are the only animals that do not form blastula. In some animals such as hydra, the blastula has only two layers- ectoderm and endoderm.
Features of animals Tissue-Cells are organized into structures called tissues Groups of common cell that perform a specific function 6. What is the only animal that lack tissue?
Features of animals Adipose (fat) tissueMuscle tissue
Visual vocabulary Match the images shown to one of the following features of animals: A. Heterotrophy E. Sexual reproduction B. Diploidy C. Tissue D. Mobility
Visual vocabulary
Visual vocabulary 4
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Body Plan Body plan-describes an animal’s shape, symmetry, and internal organization. Important terms related to some animals body plan dorsal-top Ventral-bottom Anterior-front Posterior-back or end Cephalization-a concentration of sensory structures and nerves in the anterior region of an animals body
Body plan
Body symmetry Asymmetrical- irregular shape and cannot be divided into identical halves may depend on where the organism grows Sponges tend to be asymmetrical
Body symmetry Radial symmetry-body parts are arranged around a central axis. A plane through the central axis with divide the body in equal halve in multiple directions
Body symmetry
Bilateral symmetry- A design in which there distinct right and left half A plane through the midline of the body divides the animal into halves that are mirror images
Internal body cavity Animals exhibit one of three types of body cavity: Coelom- body cavity or fluid-filled space found between body wall and digestive tract Acoelomates-posses no body cavity, tissue completely fills up the space between the body wall and the digestive tract Pseudocoelomate-false coelom, body cavity located between the mesoderm and endoderm
Internal body cavity
Animal body systems Body systems include-tissues and organs Essentials functions of tissues and organs include: Digestion support Respiration excretion Circulation Conduction of nerve impulses
Digestion The breakdown of food and the absorption of nutrient by a body Types of digestion: 1. Intracellular digestion-digestion takes place within the cell (sponges) 2. Extracellular digestion-digestion takes place outside the cells of the body, within a digestive tract.
Types of digestive cavity Gastrovascular-has only one opening (hydra and flatworm) Digestive tract (gut)-two openings, mouth and anus.
Respiration intake of oxygen and the release of carbon dioxide. Respiration may take place via gills or respiratory organs such as lungs.
Circulation The transportation of oxygen and nutrient throughout the body Open circulatory system-heart pumps fluid and nutrients through a series of blood vessels out into the body cavity The fluid washes the across the body’s tissue supplying them with oxygen and nutrient. The fluid collects in open spaces in the animal’s body, then flows back to the heart
Circulation Closed circulation Heart pumps blood through a series of blood vessels Blood vessels form a network that allows blood to flow from the heart to all the cells of the body and then back to the heart. Blood remains in the vessels and does not come in direct contact with body tissues.
Conduction of nerve impulses Nerve cells (neurons) carry messages in the form of electrical impulses to various parts of the body. Sponges lack nerve cells Animals with bilateral symmetry have clusters of neurons called ganglia At the anterior end of the body, the ganglia becomes larger and more complex, forming a brain-like structure in simple animals and the brain in more complex animals
Support Skeletal system-framework for support There are three types of skeletal system 1. Hydrostatic-consist of a closed cavity containing water that is under pressure in soft body invertebrates 2. Exoskeleton-Rigid external skeleton that encases the body of some invertebrates such as insects, clams, and crabs. 3. Endoskeleton-consist of hard material such as bone or cartilage and is embedded inside the body of vertebrates. Besides providing support, what is another function of the skeleton?
Excretion Removal of waste products from the body Please note that one of the most important toxic waste removed from the body is ammonia Aquatic invertebrates and fishes excrete ammonia into the water through the skin or gills by diffusion Terrestrial animals need to minimize water, as a result the ammonia is converted to urea.
Reproduction Necessary for the continuation of the species but not necessary for an organisms survival Types of reproduction 1. Asexual-does not involve the fusion of gametes. 2. Sexual-fusion of male and female gamete to form a new individual What is the scientific name for the male and female organs that produce the gametes?
Asexual Reproduction Please note: animals that reproduce asexually are also able to reproduce sexually
Sexual reproduction Hermaphrodites-animals that have both testes and ovaries and functions as both male and female What prevents the occurrence of self- fertilization? Simple invertebrates such as slugs, and earthworms are hermaphrodites
Sexual reproduction External fertilization-Male and female gametes are released near each other and ultimately come in contact with each other. This happens mostly in aquatic environments Internal fertilization-The union of egg and sperm take place inside the female’s body