i hate this
There is a significant change in overall size from the morula stage to the blastula stage. During the morula stage, the embryo is a solid ball of cells and is relatively small in size. However, during the blastula stage, the embryo undergoes a process called blastulation, in which the cells reorganize and form a fluid-filled cavity called the blastocoel. This results in a larger and more complex structure. The blastula stage is also characterized by the formation of two distinct cell types: the inner cell mass and the trophoblast. These cell types will give rise to the embryo and the placenta, respectively. Overall, the blastula stage represents a significant milestone in the development of the embryo.
Human embryos typically develop for approximately 8 weeks before they are considered to have reached the fetal stage of development.
Endoderm: (most internal germ layer) gives rise to the lining of the digestive tract and the organs derived from it, such as the liver and lungs of vertebrates.
Mesoderm: (middle germ layer) forms muscle, the skeletal system, and the circulatory system.
Ectoderm: (most exterior germ layer) gives rise to the outer covering and, in some phyla, to the central nervous system.
The "Umbilical cord".
The smallest baby is about the size of a small mobile phone
Seeds have various layers, consisting of a skin or shell of some kind on the outside, then layers of nutrient, and the embryo at the middle.
Hawk nests are just mats of sticks, placed on an elevated cliff, or in the fork of a tree.
Allantois, amnion, and chorion
Formation of the three germinal layers and the primitive gut
The little black dot in the egg is the part that grows into an embryo.
The embryo in a placental mammal is fully developed within the mother's uterus, sustained by the placenta, through which it receives all the nutrition it needs. Its organs are fully developed and it is able to survive outside the mother's body once it is born. It requires mothers' milk (or a suitable substitute) when it is born, but it can live independently of the mother, given the right care.
Baby marsupials are born extremely undeveloped, and are unable to survive at all outside the mother's body, until they can reach the pouch. They are born after a much shorter gestation period than a placental of equivalent size, and even the largest species of marsupial is only the size of a jellybean when it is born. After birth, it must climb up the outer fur of the mother and into the pouch where it attaches itself to a nipple. The teat swells in the joey's mouth, securing it in place so it cannot be accidentally dislodged. The joey will usually stay in the pouch for about 6-9 months, depending on the species, until it is developed enough to leave the pouch and move about independently.
I am assuming that this question should read, "Is embryo transplanting feasible with cattle?" The answer to this topic will vary greatly among cattle farmers, with many of them answering that it is not. But as the practice becomes more widespread and the techniques to perform the procedure become more common, a greater percentage of farmers may look to embryo transplanting (ET) as a long-term economic improvement to their operation.
In the simplest of terms, one of the best cows in the herd for production (and any other characteristics the farmer wishes to propagate) is chosen to be the DONOR MOTHER. This cow is given a complex series of hormone injections that will cause her to ovulate with a great number of eggs, such as 10 or more. The donor cow is bred, usually artificially, to the best bull that money can buy, which fertilizes a great number of these eggs.
Ten days later, the donor cow is FLUSHED, which is a process of extracting the eggs through a tube while injecting a flushing fluid simultaneously. This process is normally handled by a veterinarian.
Embryos are usually analyzed under a microscope for any abnormalities. The healthy ones are saved, and can be stored indefinitely in liquid nitrogen at -160 degrees F.
SURROGATE MOTHERS in the herd are then determined, either by forcing ovulation through injection, or by patiently waiting for their cycle, and instead of breeding the cow, a fertilized embryo is placed in the uterus instead, using a pipette-and-plunger type of tool.
The costs involved: shots to the donor cow are about $200 total, and the flushing cost and embryo selection is about $300. Because of today's availability of "sexed semen", the farmer can even exert influence on the number of female calves that will be produced. Let's say the female rate is 80% and there are 10 viable embryos. For most farmers, propagation of female genetics is the goal. There are those who produce bulls for the national market, but they are the minority. This group has used ET for decades already.
So, we have 8 potential heifers from a $500 expense, and lets say 25% of these embryos fail, leaving us with 6 viable heifers. We have implanted 8 surrogate mothers (remember 2 failed). So we saved the breeding and semen costs for the six successful mothers, to the tune of about $120. So now the true cash outlay for the farmer is $380 for 6 viable heifers that are GENETICALLY SUPERIOR to probably any of the other calves in his herd.
Here's the benefit: for a dairy farm, 3 years later these heifers are milking cows, and produce just 1,000 lbs. of more milk each year than their peers. This is a value of $130 per animal per year, or $780 per year for the half dozen animals that were ET produced. If these animals have a 5-year production life (and that is realistic) they have returned a gross ADDITIONAL milk production value of $3900. This was with the original $380 invested. Ten times the money in 8 years.
There are other long-term benefits to the propagation of superior genetics such as: better feet and legs, better feed to milk conversion (or feed to meat conversion for beef farmers) more longevity, more size, straighter legs, larger udders, etc. It really depends on the focus of the ET selection process.
ET requires a great deal of management with regard to sanitation, to TIMING, and to care in selection. One must remember that all of the bad traits are propagated as well. But for farmers who already conduct their own artificial inseminations (and many do) the process of embryo transplanting is very similar. As economic margins on the farm continue to tighten, farmers will look for ways to develop greater production per unit in order to be able to meet ever rising costs such as taxes, insurance, and land payments.
Echinoderms such as starfish and similar marine animals with radially symmetrical bodies have bone-like calcareous skeletal plates in their skin
The mammal embryo receives its nutrients from the mother through the placenta. The placenta allows nutrients to travel from the mother's system to the embryo's, and for waste products to leave the embryo's system so they can be disposed of by the mothers.
A mammal embryo is the developing baby inside the mother.
The stage of a multicellular organism that develops from a zygote.
Most reptiles simply abandon their eggs to 'fate' once they're laid. Some species of lizards and snakes will stay close-by and actively discourage anything from disturbing the 'nest'. The majority of animals know instinctively to avoid contact with reptiles.
evolution from a distant common ancestor