What Are Some Traits Of An Animal

Learning Objectives

By the stop of this section, you volition exist able to:

• List the features that distinguish the animal kingdom from other kingdoms
• Explicate the processes of animal reproduction and embryonic evolution
• Draw the bureaucracy of basic animal nomenclature
• Compare and dissimilarity the embryonic development of protostomes and deuterostomes

Even though members of the beast kingdom are incredibly diverse, animals share mutual features that distinguish them from organisms in other kingdoms. All animals are eukaryotic, multicellular organisms, and nearly all animals have specialized tissues. Most animals are motile, at least during sure life stages. Animals require a source of food to grow and develop. All animals are heterotrophic, ingesting living or expressionless organic matter. This course of obtaining energy distinguishes them from autotrophic organisms, such every bit most plants, which make their own nutrients through photosynthesis and from fungi that digest their food externally. Animals may be carnivores, herbivores, omnivores, or parasites (Figure 15.2). Virtually animals reproduce sexually: The offspring pass through a series of developmental stages that establish a determined trunk program, unlike plants, for example, in which the verbal shape of the trunk is indeterminate. The torso plan refers to the shape of an animal.

Figure 15.2 All animals that derive energy from nutrient are heterotrophs. The (a) black bear 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 phase in mosquitos and its developed phase infesting the hearts of dogs and other mammals, as shown here. (credit a: modification of piece of work past USDA Forest Service; credit b: modification of piece of work by Clyde Robinson)

Complex Tissue Construction

A hallmark trait of animals is specialized structures that are differentiated to perform unique functions. As multicellular organisms, near animals develop specialized cells that group together into tissues with specialized functions. A tissue is a collection of similar cells that had a common embryonic origin. At that place are four primary types of creature tissues: nervous, muscle, connective, and epithelial. Nervous tissue contains neurons, or nervus cells, which transmit nerve impulses. Muscle tissue contracts to cause all types of body movement from locomotion of the organism to movements inside the body itself. Animals also have specialized connective tissues that provide many functions, including transport and structural support. Examples of connective tissues include blood and os. Connective tissue is comprised of cells separated by extracellular cloth fabricated of organic and inorganic materials, such as the protein and mineral deposits of bone. Epithelial tissue covers the internal and external surfaces of organs within the animate being body and the external surface of the trunk of the organism.

Link to Learning

Concept in Action

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

Animate being Reproduction and Development

Well-nigh animals have diploid body (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. About animals undergo sexual reproduction, while many also accept mechanisms of asexual reproduction.

Sexual Reproduction and Embryonic Development

Nearly all animal species are capable of reproducing sexually; for many, this is the only mode of reproduction possible. This distinguishes animals from fungi, protists, and bacteria, where asexual reproduction is common or sectional. During sexual reproduction, the male and female person gametes of a species combine in a procedure called fertilization. Typically, the small, motile male sperm travels to the much larger, sessile female egg. Sperm course 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 be internal, especially in land animals, or external, as is mutual in many aquatic species.

After 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 1 of the master ways scientists classify high-level groups of animals. During development, beast cells specialize and form tissues, determining their future morphology and physiology. In many animals, such as mammals, the young resemble the adult. Other animals, such equally some insects and amphibians, undergo complete metamorphosis in which individuals enter one or more larval stages. For these animals, the young and the adult have different diets and sometimes habitats. In other species, a process 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 skin) until they reach the final adult form.

Asexual Reproduction

Asexual reproduction, unlike sexual reproduction, produces offspring genetically identical to each other and to the parent. A number of creature species—especially those without backbones, merely 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 nigh common forms of asexual reproduction for stationary aquatic animals include budding and fragmentation, in which office of a parent individual tin split and abound into a new individual. In contrast, a form of asexual reproduction found in certain invertebrates and rare vertebrates is called parthenogenesis (or "virgin starting time"), in which unfertilized eggs develop into new offspring.

Nomenclature Features of Animals

Animals are classified according to morphological and developmental characteristics, such as a torso plan. With the exception of sponges, the creature trunk programme is symmetrical. This means that their distribution of body parts is balanced along an axis. Additional characteristics that contribute to fauna nomenclature include the number of tissue layers formed during development, the presence or absence of an internal trunk cavity, and other features of embryological development.

Visual Connection

Visual Connectedness

Figure 15.3 The phylogenetic tree of animals is based on morphological, fossil, and genetic evidence.

Which of the following statements is false?

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

Body Symmetry

Animals may be asymmetrical, radial, or bilateral in form (Figure 15.4). Asymmetrical animals are animals with no pattern or symmetry; an example of an asymmetrical fauna is a sponge (Figure 15.4a). An organism with radial symmetry (Figure 15.4b) has a longitudinal (up-and-downward) orientation: Whatever airplane cut along this up–down centrality produces roughly mirror-image halves. An example of an organism with radial symmetry is a sea anemone.

Effigy 15.4 Animals showroom dissimilar types of body symmetry. The (a) sponge is asymmetrical and has no planes of symmetry, the (b) body of water anemone has radial symmetry with multiple planes of symmetry, and the (c) goat has bilateral symmetry with i plane of symmetry.

Bilateral symmetry is illustrated in Effigy 15.4c using a goat. The caprine animal besides has upper and lower sides to it, but they are not symmetrical. A vertical aeroplane cut from front end to dorsum separates the animal into roughly mirror-image right and left sides. Animals with bilateral symmetry also have a "head" and "tail" (anterior versus posterior) and a back and underside (dorsal versus ventral).

Link to Learning

Concept in Action

Sentinel this video to see a quick sketch of the different types of trunk symmetry.

Layers of Tissues

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

Figure 15.5 During embryogenesis, diploblasts develop two 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 trunk cavity derived from mesoderm, chosen a coelom (pr. run into-LŌM). This epithelial-lined crenel is a space, normally filled with fluid, which lies between the digestive organization and the body wall. It houses organs such equally the kidneys and spleen, and contains the circulatory organization. Triploblasts that do not develop a coelom are called acoelomates, and their mesoderm region is completely filled with tissue, although they have a gut crenel. Examples of acoelomates include the flatworms. Animals with a true coelom are called eucoelomates (or coelomates) (Figure 15.half dozen). 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 trunk cavity that is derived partly from mesoderm and partly from endoderm tissue. These animals are called pseudocoelomates. Roundworms are examples of pseudocoelomates. New information on the relationships of pseudocoelomates suggest that these phyla are not closely related and then the development of the pseudocoelom must have occurred more than in one case (Figure fifteen.iii). True coelomates can be further characterized based on features of their early embryological development.

Figure 15.six Triploblasts may be acoelomates, eucoelomates, or pseudocoelomates. Eucoelomates have a body crenel inside the mesoderm, called a coelom, which is lined with mesoderm tissue. Pseudocoelomates have a like body crenel, but it is lined with mesoderm and endoderm tissue. (credit a: modification of work by 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 two groups based on differences in their early embryonic development. Protostomes include phyla such as arthropods, mollusks, and annelids. Deuterostomes include the chordates and echinoderms. These two groups are named from which opening of the digestive cavity develops first: mouth or anus. The word protostome comes from Greek words meaning "mouth first," and deuterostome originates from words meaning "mouth 2nd" (in this case, the anus develops commencement). This difference reflects the fate of a structure called the blastopore (Figure xv.7), which becomes the mouth in protostomes and the anus in deuterostomes. Other developmental characteristics differ between protostomes and deuterostomes, including the style of formation of the coelom and the early on cell partition of the embryo.

Figure 15.vii Eucoelomates can be divided into two groups, protostomes and deuterostomes, based on their early on embryonic development. 2 of these differences include the origin of the mouth opening and the way in which the coelom is formed.

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

Posted by: martinezthilvely.blogspot.com

Share this post