Search
- https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Map%3A_Raven_Biology_12th_Edition/19%3A_Cellular_Mechanisms_of_Development/19.02%3A_Cell_Division/19.2.03%3A_CleavageCleavage refers to the early cell divisions that occur as a fertilized egg begins to develop into an embryo.
- https://bio.libretexts.org/Bookshelves/Evolutionary_Developmental_Biology/Evolutionary_Developmental_Biology_(Rivera)/03%3A_Cleavage_and_Gastrulation/3.2%3A_Cell_Division_and_Movement%3A_Cleavage_-_Frog_Gastrulation_and_the_Dorsal_Lip_of_the_BlastoporeOver the course of gastrulation, the red area (future mesoderm) in Figure 5 will involute under the blue area (future ectoderm) and extend to form a layer at the roof of the blastocoel (Figures 3 and ...Over the course of gastrulation, the red area (future mesoderm) in Figure 5 will involute under the blue area (future ectoderm) and extend to form a layer at the roof of the blastocoel (Figures 3 and 4). This involution occurs most extensively at the dorsal side of the embryo (the side opposite sperm entry), but also occurs along the rest of the "blastopore lip". To visualize the blastopore lip, open your mouth wide.
- https://bio.libretexts.org/Courses/Norco_College/OpenStax_Biology_2e_for_Norco_College/27%3A_Introduction_to_Animal_Diversity/27.02%3A_Features_of_the_Animal_KingdomEpithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, as well as the layers of cells that make up the ducts of the liver and glands of advanced ani...Epithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, as well as the layers of cells that make up the ducts of the liver and glands of advanced animals, for example. The presence of a Hox gene in the Placozoa, in addition to similarities in the genomic organization of the Placozoa, Cnidaria and Bilateria, has led to the inclusion of the three groups in a “Parahoxozoa” clade.
- https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/General_Biology_1e_(OpenStax)/5%3A_Biological_Diversity/27%3A_Introduction_to_Animal_Diversity/27.1%3A_Features_of_the_Animal_KingdomEpithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous i...Epithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous in the animal kingdom, that is, the genetic sequences of Hox genes and their positions on chromosomes are remarkably similar across most animals because of their presence in a common ancestor, from worms to flies, mice, and humans (Figure \(\PageIndex{4}\)).
- https://bio.libretexts.org/Courses/Saint_Mary's_College_Notre_Dame_IN/Foundations_of_Form_and_Function/04%3A_Intro_to_Animals/4.01%3A_Some_General_Features_of_AnimalsEpithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous i...Epithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous in the animal kingdom, that is, the genetic sequences of Hox genes and their positions on chromosomes are remarkably similar across most animals because of their presence in a common ancestor, from worms to flies, mice, and humans (Figure \(\PageIndex{4}\)).
- https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Biology_(Kimball)/14%3A_Embryonic_Development_and_its_Regulation/14.01%3A_Embryonic_DevelopmentThis page outlines embryonic development in animals, which includes four stages: Cleavage (rapid cell division of the zygote), Patterning (cell organization and body axis establishment), Differentiati...This page outlines embryonic development in animals, which includes four stages: Cleavage (rapid cell division of the zygote), Patterning (cell organization and body axis establishment), Differentiation (activation of zygotic genes for specific cell types), and Growth. It emphasizes the transition from maternal mRNA to the embryo's genome. Research on frogs and snails illustrates the significance of mRNA distribution and protein gradients during early development.
- https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Map%3A_Raven_Biology_12th_Edition/32%3A_Animal_Diversity_and_the_Evolution_of_Body_Plans/32.01%3A_Some_General_Features_of_AnimalsEpithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous i...Epithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous in the animal kingdom, that is, the genetic sequences of Hox genes and their positions on chromosomes are remarkably similar across most animals because of their presence in a common ancestor, from worms to flies, mice, and humans (Figure \(\PageIndex{4}\)).
- https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Biology_(Kimball)/14%3A_Embryonic_Development_and_its_Regulation/14.03%3A_CleavageThis page describes cleavage as a crucial early stage of cell division in embryo development post-fertilization, differentiating between holoblastic cleavage (complete division in low-yolk eggs like f...This page describes cleavage as a crucial early stage of cell division in embryo development post-fertilization, differentiating between holoblastic cleavage (complete division in low-yolk eggs like frogs) and meroblastic cleavage (incomplete division in high-yolk eggs like birds). It highlights how meroblastic cleavage occurs in a limited cytoplasmic region, resulting in multiple nuclei and a significant yolk mass, which aids in forming a normal-sized embryo from the fertilized egg.
- https://bio.libretexts.org/Workbench/General_Biology_I_and_II/05%3A_Unit_V-_Biological_Diversity/5.06%3A_Introduction_to_Animal_Diversity/5.6.03%3A_Features_of_the_Animal_KingdomEpithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous i...Epithelial tissues include the epidermis of the integument, the lining of the digestive tract and trachea, and make up the ducts of the liver and glands of advanced animals. Hox genes are homologous in the animal kingdom, that is, the genetic sequences of Hox genes and their positions on chromosomes are remarkably similar across most animals because of their presence in a common ancestor, from worms to flies, mice, and humans (Figure \(\PageIndex{4}\)).
- https://bio.libretexts.org/Bookshelves/Evolutionary_Developmental_Biology/Evolutionary_Developmental_Biology_(Rivera)/03%3A_Cleavage_and_GastrulationCleavage stages of embryogenesis are typically very similar across animals. During cleavage, a single cell embryo rapidly divides to form a ball of cells, called a blastula. This ball may be hollow in...Cleavage stages of embryogenesis are typically very similar across animals. During cleavage, a single cell embryo rapidly divides to form a ball of cells, called a blastula. This ball may be hollow inside, have a hollow region, or be fairly solid. Gastrulation refers to a time of great flux in animal embryos. During gastrulation the cells produced during cleavage begin to move relative to each other. As they move, they change their local environment and come into contact with new cells.
- https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Biology_(Kimball)/14%3A_Embryonic_Development_and_its_Regulation/14.02%3A_Frog_EmbryologyThis page describes the development of frog eggs into tadpoles. After fertilization, the zygote undergoes cleavage and forms a blastula with smaller cells. Gastrulation creates germ layers for body ti...This page describes the development of frog eggs into tadpoles. After fertilization, the zygote undergoes cleavage and forms a blastula with smaller cells. Gastrulation creates germ layers for body tissues. The Spemann organizer prompts ectoderm development into neural tissue, essential for the brain and spinal cord. The tadpole hatches as a complete structure and continues to grow by feeding, incorporating organic matter.
