Animal Diversity Design by Owen Borville 11.7.2024 Biology 27
All animals are heterotrophic (=requires food and consume plants and other animals). (autotrophic=make own food=plants). Animals can be carnivores, herbivores, omnivores, or parasites. Animals have complex tissue structure. Animals must be motile (mobile) to catch food). Most animals are diploid (two sets of chromosomes) and multicellular. Most animals don't have alternation of generations.
The body plan of an animal is the morphology of the animal, including all development stages from embryo to larva (larvae) to metamorphosis to adult.
Complex tissue structures in animals include sensory structures that help animals find food, run from predators, and travel in their environment. These sensory structures include muscle tissue coordinated by neural communications, nerve tissue, and structures for intercellular communication. There is connective tissue in the bones of vertebrates. Epithelial tissues of the epidermis of the digestive tract and trachea, liver, and glands.
The animal kingdom includes Parazoa or Porifera (sponges), Placozoa, Cnidaria (jellyfish), Ctenophora, and Bilateria. Most animals also undergo sexual reproduction, but some use asexual reproduction. During sexual reproduction, the haploid gametes of the male and female individuals of a species combine in a process called fertilization. This process produces a diploid fertilized egg called a zygote.
Those animals that use asexual reproduction commonly undergo budding and fragmentation processes, where part of a parent organism separates or breaks off to become an identical offspring. Some invertebrate and vertebrate animals reproduce without fertilization, or parthenogenesis (virgin birth) through the female.
In animals, the zygote progresses through a series of developmental stages, during which primary germ layers (ectoderm, endoderm, and mesoderm) are established and reorganize to form an embryo, while tissues begin to specialize into organs and organ systems.
Animal development begins with cleavage, or mitotic cell divisions, of the zygote. The cells resulting from subdivision of the material of the egg in this way are called blastomeres. Three cell divisions transform the single-celled zygote into an eight-celled structure. After further cell division and rearrangement of existing cells, a solid morula is formed, followed by a hollow structure called a blastula, which in only hollow in invertebrates but not vertebrates.
Further cell division results in gastrulation, the formulation of the digestive cavity, and the embryonic germ layers. These germ layers are programmed to develop into certain tissue types, organs, and organ systems during a process called organogenesis. Some organisms (diploblastic) have two germ layers (endoderm and ectoderm) and others (triploblastic) have three germ layers (endoderm, ectoderm, mesoderm).
Embryo development steps=(1) zygote (2) cleavage to eight-cell stage (3) cleavage to blastula (4) gastrulation to gastrula.
Some animal larvae are different in morphology than the adult (incomplete metamorphosis) such as grasshoppers and development of wings. In complete metamorphosis, such as in insects and echinoderms, the embryo develops into one or more feeding larval stages that may differ greatly in structure and function from the adult, and the larvae and adult may have different diets.
Homeobox (hox) genes cause many embryos of different animals to look similar in morphology, even among insects, amphibians, mammals, and humans. Hox genes are powerful control genes because they can encode transcription factors that control the expression of numerous other genes. Vertebrates have four or more sets of hox genes, while invertebrates have only one set.
Animal classification is commonly based on body plan symmetry and developmental pathway characteristics.
Animal symmetry of body plan includes radial, bilateral, and asymmetrical symmetry. Radial symmetry is the arrangement of body parts around a central axis, including jellyfish and sea anemones, sea stars, sand dollars and sea urchins. Bilateral symmetry is found in butterflies, where a single plane is divided into equal halves and the organism can be divided into two mirror images of each other. Asymmetry is found in sponges.
Animal classification based on embryonic development
The animals that display radial, biradial, or rotational symmetry develop two germ layers, an inner layer (endoderm or mesendoderm) and an outer layer (ectoderm). These animals are called diploblasts, and have a nonliving middle layer between the endoderm and ectoderm.
Animals (usually those with bilateral symmetry) develop three tissue layers including: an inner layer (endoderm), an outer layer (ectoderm), and a middle layer (mesoderm). Animals with three tissue layers are called triploblasts.
The germ layers help form specific body tissues and organs. Endoderm (digestive tract and trachea), ectoderm (epithelial covering on body surface and the central nervous system), and mesoderm (muscle tissues, connective tissues, kidneys, spleen).
Additional classification of animals with three germ layers include those with an internal body cavity from the mesoderm called the coelom, which is filled with fluid and houses many organs from the digestive, urinary, reproductive, respiratory, cardiovascular, arteries and veins.
Triploblasts that do not develop a coelom are called acoelomates, where tissue develops along with a gut. Animals with a coelom are called eucoelomates or coelomates. Another group of triploblasts has a different type of coelom lined partly with the mesoderm and partly with the endoderm. These animals are called pseudocoelomates (ex. roundworms).
Animals can be further divided by embryonic development of the mouth. The blastophore is the opening that connects the gut cavity to the outside of the embryo, and most animals have openings at both ends of the gut, the mouth and the anus. In protostomes, the mouth develops at the blastopore (arthropods, mollusks, and annelids). In deuterostomes, the mouth develops at the other end of the gut and the anus develops at the site of the blastopore (chordates and echinoderms).
The coelom of most protostomes is formed by a process called schizocoely, where the mesoderm is the product of specific blastomeres. Deuterostomes are different in that their coelom develops by a process called enterocoely, where the mesoderm develops as pouches that are pinched off from the endoderm tissue, fuse and expand to form the coelom.
Protostomes undergo spiral cleavage, where the cells of one pole of the embryo are rotated and misaligned with the cells in the opposite pole. Deuterostomes undergo radial cleavage, where cleavage axes are either parallel or perpendicular to the polar axis, resulting in parallel alignment of the cells between the two poles.
Another cleavage classification is between the types of cleavage in protostomes and deuterostomes is the resultant blastomeres. Protostomes also undergo determinate cleavage, where the developmental fate of each embryonic cell is already determined. Deuterostomes also undergo indeterminate cleavage, where cells are not fully committed to develop into specific cell types. Damaged or removed blastomeres in a protostome can stop the embryo from developing, however, in a deuterostome, this would not occur.
Evolutionists use phylogeny to determine branching sequences of evolution between phyla. In addition to morphology and the fossil record, scientists today use advanced molecular technologies that analyze DNA and RNA genetic material in order to determine phylogenies. However, creationist minded scientists continue to assert that evolutionists make assumptions about evolutionary links that cannot be verified. The observational evidence based on the data gives strong evidence for intelligent design for each species kind and not branches of evolutionary links that cannot be verified. There may be similarities in morphology, fossil record, and even DNA structure, however species kinds are the product of an intelligent design.
All animals are heterotrophic (=requires food and consume plants and other animals). (autotrophic=make own food=plants). Animals can be carnivores, herbivores, omnivores, or parasites. Animals have complex tissue structure. Animals must be motile (mobile) to catch food). Most animals are diploid (two sets of chromosomes) and multicellular. Most animals don't have alternation of generations.
The body plan of an animal is the morphology of the animal, including all development stages from embryo to larva (larvae) to metamorphosis to adult.
Complex tissue structures in animals include sensory structures that help animals find food, run from predators, and travel in their environment. These sensory structures include muscle tissue coordinated by neural communications, nerve tissue, and structures for intercellular communication. There is connective tissue in the bones of vertebrates. Epithelial tissues of the epidermis of the digestive tract and trachea, liver, and glands.
The animal kingdom includes Parazoa or Porifera (sponges), Placozoa, Cnidaria (jellyfish), Ctenophora, and Bilateria. Most animals also undergo sexual reproduction, but some use asexual reproduction. During sexual reproduction, the haploid gametes of the male and female individuals of a species combine in a process called fertilization. This process produces a diploid fertilized egg called a zygote.
Those animals that use asexual reproduction commonly undergo budding and fragmentation processes, where part of a parent organism separates or breaks off to become an identical offspring. Some invertebrate and vertebrate animals reproduce without fertilization, or parthenogenesis (virgin birth) through the female.
In animals, the zygote progresses through a series of developmental stages, during which primary germ layers (ectoderm, endoderm, and mesoderm) are established and reorganize to form an embryo, while tissues begin to specialize into organs and organ systems.
Animal development begins with cleavage, or mitotic cell divisions, of the zygote. The cells resulting from subdivision of the material of the egg in this way are called blastomeres. Three cell divisions transform the single-celled zygote into an eight-celled structure. After further cell division and rearrangement of existing cells, a solid morula is formed, followed by a hollow structure called a blastula, which in only hollow in invertebrates but not vertebrates.
Further cell division results in gastrulation, the formulation of the digestive cavity, and the embryonic germ layers. These germ layers are programmed to develop into certain tissue types, organs, and organ systems during a process called organogenesis. Some organisms (diploblastic) have two germ layers (endoderm and ectoderm) and others (triploblastic) have three germ layers (endoderm, ectoderm, mesoderm).
Embryo development steps=(1) zygote (2) cleavage to eight-cell stage (3) cleavage to blastula (4) gastrulation to gastrula.
Some animal larvae are different in morphology than the adult (incomplete metamorphosis) such as grasshoppers and development of wings. In complete metamorphosis, such as in insects and echinoderms, the embryo develops into one or more feeding larval stages that may differ greatly in structure and function from the adult, and the larvae and adult may have different diets.
Homeobox (hox) genes cause many embryos of different animals to look similar in morphology, even among insects, amphibians, mammals, and humans. Hox genes are powerful control genes because they can encode transcription factors that control the expression of numerous other genes. Vertebrates have four or more sets of hox genes, while invertebrates have only one set.
Animal classification is commonly based on body plan symmetry and developmental pathway characteristics.
Animal symmetry of body plan includes radial, bilateral, and asymmetrical symmetry. Radial symmetry is the arrangement of body parts around a central axis, including jellyfish and sea anemones, sea stars, sand dollars and sea urchins. Bilateral symmetry is found in butterflies, where a single plane is divided into equal halves and the organism can be divided into two mirror images of each other. Asymmetry is found in sponges.
Animal classification based on embryonic development
The animals that display radial, biradial, or rotational symmetry develop two germ layers, an inner layer (endoderm or mesendoderm) and an outer layer (ectoderm). These animals are called diploblasts, and have a nonliving middle layer between the endoderm and ectoderm.
Animals (usually those with bilateral symmetry) develop three tissue layers including: an inner layer (endoderm), an outer layer (ectoderm), and a middle layer (mesoderm). Animals with three tissue layers are called triploblasts.
The germ layers help form specific body tissues and organs. Endoderm (digestive tract and trachea), ectoderm (epithelial covering on body surface and the central nervous system), and mesoderm (muscle tissues, connective tissues, kidneys, spleen).
Additional classification of animals with three germ layers include those with an internal body cavity from the mesoderm called the coelom, which is filled with fluid and houses many organs from the digestive, urinary, reproductive, respiratory, cardiovascular, arteries and veins.
Triploblasts that do not develop a coelom are called acoelomates, where tissue develops along with a gut. Animals with a coelom are called eucoelomates or coelomates. Another group of triploblasts has a different type of coelom lined partly with the mesoderm and partly with the endoderm. These animals are called pseudocoelomates (ex. roundworms).
Animals can be further divided by embryonic development of the mouth. The blastophore is the opening that connects the gut cavity to the outside of the embryo, and most animals have openings at both ends of the gut, the mouth and the anus. In protostomes, the mouth develops at the blastopore (arthropods, mollusks, and annelids). In deuterostomes, the mouth develops at the other end of the gut and the anus develops at the site of the blastopore (chordates and echinoderms).
The coelom of most protostomes is formed by a process called schizocoely, where the mesoderm is the product of specific blastomeres. Deuterostomes are different in that their coelom develops by a process called enterocoely, where the mesoderm develops as pouches that are pinched off from the endoderm tissue, fuse and expand to form the coelom.
Protostomes undergo spiral cleavage, where the cells of one pole of the embryo are rotated and misaligned with the cells in the opposite pole. Deuterostomes undergo radial cleavage, where cleavage axes are either parallel or perpendicular to the polar axis, resulting in parallel alignment of the cells between the two poles.
Another cleavage classification is between the types of cleavage in protostomes and deuterostomes is the resultant blastomeres. Protostomes also undergo determinate cleavage, where the developmental fate of each embryonic cell is already determined. Deuterostomes also undergo indeterminate cleavage, where cells are not fully committed to develop into specific cell types. Damaged or removed blastomeres in a protostome can stop the embryo from developing, however, in a deuterostome, this would not occur.
Evolutionists use phylogeny to determine branching sequences of evolution between phyla. In addition to morphology and the fossil record, scientists today use advanced molecular technologies that analyze DNA and RNA genetic material in order to determine phylogenies. However, creationist minded scientists continue to assert that evolutionists make assumptions about evolutionary links that cannot be verified. The observational evidence based on the data gives strong evidence for intelligent design for each species kind and not branches of evolutionary links that cannot be verified. There may be similarities in morphology, fossil record, and even DNA structure, however species kinds are the product of an intelligent design.