Embryo Development in Different Species:
– Embryo development varies across species.
– In viviparous animals, offspring are considered embryos inside the parent.
– Different species have unique developmental milestones.
– Embryonic growth and development differ in animals that hatch from eggs and viviparous animals.
– Embryos studied in biological research labs worldwide.
– Embryo research in various species like amphibians and flies.
– Embryology studies the development of animals broadly.
Assisted Reproductive Technology (ART):
– ART techniques for fertility issues in humans and animals.
– In vitro fertilization (IVF) responsible for many US births.
– Preimplantation genetic diagnosis (PGD) for genetic abnormalities.
– Controversy over genetic editing of human embryos.
– ART techniques used in selective breeding and conservation efforts.
Cryoconservation for Biodiversity Preservation:
– Cryoconservation stores reproductive materials at low temperatures.
– Seed banks and frozen zoos preserve plant and animal diversity.
– Svalbard Global Seed Vault in Norway holds a large plant collection.
– Efforts to conserve endangered species using cryoconservation.
– Importance of cryoconservation in preserving biodiversity.
Fossilized Embryos:
– Fossilized animal embryos found from Precambrian to Cambrian periods.
– Discovery of fossilized dinosaur embryos.
– Significance of fossilized embryos in understanding ancient life forms.
– References to studies and resources on fossilized embryos.
– Contributions of fossilized embryos to the field of embryology.
Research and Technological Advancements:
– Topics studied include stem cells, evolution, and gene expression.
– Nobel Prize-winning discoveries related to embryos.
– Biological processes involving embryos.
– Examples of significant discoveries from studying embryos.
– Genes responsible for body segments in Drosophila fly embryos.
An embryo is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals.
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Anatomical terminology |
The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous system, and organogenesis is the development of all the various tissues and organs of the body.
A newly developing human is typically referred to as an embryo until the ninth week after conception, when it is then referred to as a fetus. In other multicellular organisms, the word "embryo" can be used more broadly to any early developmental or life cycle stage prior to birth or hatching.