What Is The Animal Kingdom In Science

Learning Objectives

By the end of this section, yous will be able to:

• List the features that distinguish the animal kingdom from other kingdoms
• Explain the processes of beast reproduction and embryonic development
• Depict the hierarchy of basic animal nomenclature
• Compare and dissimilarity the embryonic development of protostomes and deuterostomes

Even though members of the animal kingdom are incredibly various, animals share common features that distinguish them from organisms in other kingdoms. All animals are eukaryotic, multicellular organisms, and nearly all animals have specialized tissues. About animals are motile, at least during certain life stages. Animals require a source of nutrient to abound and develop. All animals are heterotrophic, ingesting living or dead organic thing. This grade of obtaining energy distinguishes them from autotrophic organisms, such as most plants, which make their ain nutrients through photosynthesis and from fungi that digest their nutrient externally. Animals may exist carnivores, herbivores, omnivores, or parasites (Effigy 15.2). Well-nigh animals reproduce sexually: The offspring pass through a series of developmental stages that establish a determined body programme, unlike plants, for instance, in which the exact shape of the body is indeterminate. The body program refers to the shape of an animate being.

Figure 15.ii All animals that derive energy from food are heterotrophs. The (a) black behave is an omnivore, eating both plants and animals. The (b) heartworm Dirofilaria immitis is a parasite that derives energy from its hosts. It spends its larval stage in mosquitos and its developed stage infesting the hearts of dogs and other mammals, as shown here. (credit a: modification of work by USDA Forest Service; credit b: modification of work by Clyde Robinson)

Circuitous Tissue Construction

A hallmark trait of animals is specialized structures that are differentiated to perform unique functions. As multicellular organisms, most animals develop specialized cells that group together into tissues with specialized functions. A tissue is a collection of similar cells that had a mutual embryonic origin. There are four main types of animal tissues: nervous, musculus, connective, and epithelial. Nervous tissue contains neurons, or nerve cells, which transmit nerve impulses. Muscle tissue contracts to cause all types of body movement from locomotion of the organism to movements within the body itself. Animals also have specialized connective tissues that provide many functions, including transport and structural back up. Examples of connective tissues include blood and bone. 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. Epithelial tissue covers the internal and external surfaces of organs inside the animal body and the external surface of the body of the organism.

Link to Learning

Concept in Action

View this video to watch a presentation by biologist E.O. Wilson on the importance of animal diversity.

Animate being Reproduction and Evolution

Most animals take diploid torso (somatic) cells and a small number of haploid reproductive (gamete) cells produced through meiosis. Some exceptions exist: For example, in bees, wasps, and ants, the male is haploid because it develops from an unfertilized egg. Near animals undergo sexual reproduction, while many as well accept mechanisms of asexual reproduction.

Sexual Reproduction and Embryonic Evolution

Near all animal species are capable of reproducing sexually; for many, this is the but mode of reproduction possible. This distinguishes animals from fungi, protists, and leaner, where asexual reproduction is common or sectional. During sexual reproduction, the male person and female person gametes of a species combine in a process chosen fertilization. Typically, the small, motile male person sperm travels to the much larger, sessile female egg. Sperm form is diverse and includes cells with flagella or amoeboid cells to facilitate motility. Fertilization and fusion of the gamete nuclei produce a zygote. Fertilization may exist internal, particularly in land animals, or external, as is common in many aquatic species.

Later fertilization, a developmental sequence ensues as cells divide and differentiate. Many of the events in development are shared in groups of related animal species, and these events are one of the main ways scientists allocate high-level groups of animals. During evolution, animal cells specialize and grade tissues, determining their hereafter morphology and physiology. In many animals, such as mammals, the young resemble the adult. Other animals, such as some insects and amphibians, undergo complete metamorphosis in which individuals enter one or more than larval stages. For these animals, the immature and the developed have different diets and sometimes habitats. In other species, a procedure of incomplete metamorphosis occurs in which the young somewhat resemble the adults and go through a series of stages separated by molts (shedding of the peel) until they reach the final developed form.

Asexual Reproduction

Asexual reproduction, different sexual reproduction, produces offspring genetically identical to each other and to the parent. A number of creature species—especially those without backbones, but even some fish, amphibians, and reptiles—are capable of asexual reproduction. Asexual reproduction, except for occasional identical twinning, is absent in birds and mammals. The nearly common forms of asexual reproduction for stationary aquatic animals include budding and fragmentation, in which part of a parent individual can separate and grow into a new individual. In dissimilarity, a grade of asexual reproduction plant in certain invertebrates and rare vertebrates is called parthenogenesis (or "virgin beginning"), in which unfertilized eggs develop into new offspring.

Nomenclature Features of Animals

Animals are classified according to morphological and developmental characteristics, such as a body program. With the exception of sponges, the fauna body plan is symmetrical. This ways that their distribution of body parts is counterbalanced along an centrality. Additional characteristics that contribute to beast classification include the number of tissue layers formed during evolution, the presence or absence of an internal body cavity, and other features of embryological development.

Visual Connectedness

Visual Connection

Figure xv.3 The phylogenetic tree of animals is based on morphological, fossil, and genetic show.

Which of the following statements is fake?

1. Eumetazoa take specialized tissues and Parazoa do not.
2. Both acoelomates and pseudocoelomates have a body cavity.
3. Chordates are more closely related to echinoderms than to rotifers co-ordinate to the figure.
4. Some animals have radial symmetry, and some animals have bilateral symmetry.

Trunk Symmetry

Animals may be asymmetrical, radial, or bilateral in form (Figure xv.4). Asymmetrical animals are animals with no blueprint or symmetry; an example of an asymmetrical animal is a sponge (Figure 15.foura). An organism with radial symmetry (Effigy 15.4b) has a longitudinal (upwardly-and-down) orientation: Any aeroplane cut along this upward–down centrality produces roughly mirror-prototype halves. An example of an organism with radial symmetry is a ocean anemone.

Effigy 15.4 Animals showroom unlike types of body symmetry. The (a) sponge is asymmetrical and has no planes of symmetry, the (b) sea anemone has radial symmetry with multiple planes of symmetry, and the (c) caprine animal has bilateral symmetry with one airplane of symmetry.

Bilateral symmetry is illustrated in Figure 15.fourc using a goat. The caprine animal also has upper and lower sides to it, simply they are non symmetrical. A vertical plane cut from front to dorsum separates the animal into roughly mirror-image right and left sides. Animals with bilateral symmetry too have a "head" and "tail" (anterior versus posterior) and a back and underside (dorsal versus ventral).

Link to Learning

Concept in Action

Watch this video to see a quick sketch of the different types of body symmetry.

Layers of Tissues

Most creature species undergo a layering of early tissues during embryonic development. These layers are called germ layers. Each layer develops into a specific fix of tissues and organs. Animals develop either two or three embryonic germs layers (Effigy 15.5). The animals that display radial symmetry develop two germ layers, an inner layer (endoderm) and an outer layer (ectoderm). These animals are chosen diploblasts. Animals with bilateral symmetry develop three germ layers: an inner layer (endoderm), an outer layer (ectoderm), and a middle layer (mesoderm). Animals with 3 germ layers are called triploblasts.

Figure 15.5 During embryogenesis, diploblasts develop 2 embryonic germ layers: an ectoderm and an endoderm. Triploblasts develop a third layer—the mesoderm—between the endoderm and ectoderm.

Presence or Absence of a Coelom

Triploblasts may develop an internal body cavity derived from mesoderm, called a coelom (pr. run into-LŌM). This epithelial-lined cavity is a space, ordinarily filled with fluid, which lies betwixt the digestive arrangement and the torso wall. It houses organs such every bit the kidneys and spleen, and contains the circulatory system. Triploblasts that practise not develop a coelom are chosen acoelomates, and their mesoderm region is completely filled with tissue, although they have a gut cavity. Examples of acoelomates include the flatworms. Animals with a truthful coelom are called eucoelomates (or coelomates) (Figure 15.6). A true coelom arises entirely within the mesoderm germ layer. Animals such as earthworms, snails, insects, starfish, and vertebrates are all eucoelomates. A third group of triploblasts has a body cavity that is derived partly from mesoderm and partly from endoderm tissue. These animals are called pseudocoelomates. Roundworms are examples of pseudocoelomates. New data on the relationships of pseudocoelomates suggest that these phyla are not closely related and and so the development of the pseudocoelom must take occurred more than once (Figure 15.iii). True coelomates can be farther characterized based on features of their early on embryological development.

Figure 15.vi Triploblasts may be acoelomates, eucoelomates, or pseudocoelomates. Eucoelomates accept a trunk cavity within the mesoderm, called a coelom, which is lined with mesoderm tissue. Pseudocoelomates have a like body cavity, but it is lined with mesoderm and endoderm tissue. (credit a: modification of piece of work past Jan Derk; credit b: modification of work by NOAA; credit c: modification of work by USDA, ARS)

Protostomes and Deuterostomes

Bilaterally symmetrical, triploblastic eucoelomates can be divided into 2 groups based on differences in their early embryonic development. Protostomes include phyla such every bit arthropods, mollusks, and annelids. Deuterostomes include the chordates and echinoderms. These 2 groups are named from which opening of the digestive crenel develops first: mouth or anus. The give-and-take protostome comes from Greek words significant "mouth outset," and deuterostome originates from words meaning "mouth second" (in this instance, the anus develops showtime). This difference reflects the fate of a structure called the blastopore (Figure xv.7), which becomes the oral fissure in protostomes and the anus in deuterostomes. Other developmental characteristics differ between protostomes and deuterostomes, including the mode of germination of the coelom and the early prison cell division of the embryo.

Effigy 15.7 Eucoelomates can be divided into 2 groups, protostomes and deuterostomes, based on their early embryonic evolution. 2 of these differences include the origin of the oral fissure opening and the fashion in which the coelom is formed.

Source: https://openstax.org/books/concepts-biology/pages/15-1-features-of-the-animal-kingdom

Posted by: mirandalacceir.blogspot.com

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