1) How is a Gastrula different from the Blastula?
1) How is a Gastrula different from the Blastula?
The blastula is the developmental stage that forms before the gastrula. During embryonic development, the blastula undergoes a process called gastrulation, which results in the formation of the gastrula.
The correct order of developmental sequence is: Fertilization -> Zygote -> Cleavage -> Blastula -> Gastrula -> Embryo -> Meiosis -> Adult.
The blastula is an embryonic structure that is formed from one cell layer. This later forms the three cell layered gastrula. All of the layers of the organism are formed from these three layers. See the link below:
Haploid Gametes Egg Sperm Fertilization Zygote Blastula Gastrula Embryo Fetus
Distribution of yolk cells.
Blastula is a hollow structure, that consists of a single layer of morphologically distinct cells, trophoblasts, forming the periphery of sphere. The space enclosed within trophoblast layer is filled with a fluid called as blastoceol. At one end of blastula, there is a cluster of undifferentiated cells, known as inner cell mass. During the gastrula stage the inner cell mass began to align in a plane (like a disk) giving rise to three distinct germ layers from which the future organs will develop.
The frog blastula is formed through holoblastic cleavage, resulting in a multicellular blastula with a fluid-filled cavity (blastocoel). In contrast, the sea star blastula is formed through radial holoblastic cleavage, leading to a solid blastula with no blastocoel. Additionally, the frog blastula undergoes gastrulation to form a gastrula with three germ layers, while the sea star blastula directly develops into a bipinnaria larva without gastrulation.
The three primary germ layers in the gastrula are the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer). Each layer gives rise to different tissues and organs in the developing embryo.
gastrula
gastrula
Gastrula has cell layers that will later develop into different body structures. The three primary germ layers - ectoderm, mesoderm, and endoderm - are formed during gastrulation and give rise to various tissues and organs in the developing embryo.