depending on the blastopore fate of its members

Depending on the blastopore fate of its members series#

Fertilization and fusion of the gamete nuclei produce a zygote. Sperm form is diverse and includes cells with flagella or amoeboid cells to facilitate motility. Typically, the small, motile male sperm travels to the much larger, sessile female egg. During sexual reproduction, the male and female gametes of a species combine in a process called fertilization. This distinguishes animals from fungi, protists, and bacteria, where asexual reproduction is common or exclusive. Sexual Reproduction and Embryonic DevelopmentĪlmost all animal species are capable of reproducing sexually for many, this is the only mode of reproduction possible. Most animals undergo sexual reproduction, while many also have mechanisms of asexual reproduction. Some exceptions exist: For example, in bees, wasps, and ants, the male is haploid because it develops from an unfertilized egg. Most animals have diploid body (somatic) cells and a small number of haploid reproductive (gamete) cells produced through meiosis. Wilson on the importance of animal diversity. View this video to watch a presentation by biologist E.O. Epithelial tissue covers the internal and external surfaces of organs inside the animal body and the external surface of the body of the organism. Connective tissue is comprised of cells separated by extracellular material made of organic and inorganic materials, such as the protein and mineral deposits of bone. Examples of connective tissues include blood and bone. Animals also have specialized connective tissues that provide many functions, including transport and structural support. Muscle tissue contracts to cause all types of body movement from locomotion of the organism to movements within the body itself. Nervous tissue contains neurons, or nerve cells, which transmit nerve impulses. There are four main types of animal tissues: nervous, muscle, connective, and epithelial. A tissue is a collection of similar cells that had a common embryonic origin. As multicellular organisms, most animals develop specialized cells that group together into tissues with specialized functions. (credit a: modification of work by USDA Forest Service credit b: modification of work by Clyde Robinson) Complex Tissue StructureĪ hallmark trait of animals is specialized structures that are differentiated to perform unique functions. It spends its larval stage in mosquitos and its adult stage infesting the hearts of dogs and other mammals, as shown here. The (b) heartworm Dirofilaria immitis is a parasite that derives energy from its hosts. The (a) black bear is an omnivore, eating both plants and animals. The body plan refers to the shape of an animal.įigure 15.2 All animals that derive energy from food are heterotrophs.

Depending on the blastopore fate of its members series#

Most animals reproduce sexually: The offspring pass through a series of developmental stages that establish a determined body plan, unlike plants, for example, in which the exact shape of the body is indeterminate. Animals may be carnivores, herbivores, omnivores, or parasites ( Figure 15.2). This form of obtaining energy distinguishes them from autotrophic organisms, such as most plants, which make their own nutrients through photosynthesis and from fungi that digest their food externally. All animals are heterotrophic, ingesting living or dead organic matter. Animals require a source of food to grow and develop. Most animals are motile, at least during certain life stages. All animals are eukaryotic, multicellular organisms, and almost all animals have specialized tissues. Compare and contrast the embryonic development of protostomes and deuterostomesĮven though members of the animal kingdom are incredibly diverse, animals share common features that distinguish them from organisms in other kingdoms.Describe the hierarchy of basic animal classification.Explain the processes of animal reproduction and embryonic development.List the features that distinguish the animal kingdom from other kingdoms.Learning Objectives By the end of this section, you will be able to: