Question

Установите последовательность этапов размножения и развития лягушек. 1) Появление у головастиков передних конечностей 2) Оплодотворение икры самцами 3) Исчезновение хвоста 4) Откладка самками икры в воду 5) Появление личинок с ветвистыми наружными жабрами 6) Появление у головастиков задних конечностей

Answer 1

4)Откладка самки икры в воду ;
2)Оплодотворение икры самцами;
5)Появление личинок с ветвистыми наружными жабрами;
6)Появление у головастиков задних конечностей;
1)Появление у головастиков передних конечностей ;
3)Исчезновение хвоста;

Answer 2

Sequence of Reproduction and Development in Frogs

The reproduction and development of frogs involve several stages. Here is the sequence of these stages:

1. Egg Laying: Female frogs lay eggs in water, typically in ponds, lakes, or streams. The eggs are laid in clusters or masses and are covered with a jelly-like substance for protection.

2. Fertilization: After the eggs are laid, the male frogs release sperm onto the eggs to fertilize them. This process is known as external fertilization since it occurs outside the female's body.

3. Embryonic Development: The fertilized eggs develop into embryos within the protective jelly. Over time, the embryos undergo cell division and differentiation. Eventually, the embryos develop into tadpoles.

4. Tadpole Stage: Tadpoles are the larval stage of frogs. They have a long tail, gills for breathing underwater, and no limbs. Tadpoles feed on algae and other small organisms in the water. During this stage, they undergo significant growth and development.

5. Metamorphosis: As tadpoles continue to grow, they undergo a process called metamorphosis. During metamorphosis, the tadpoles gradually develop hind limbs, followed by forelimbs. Their tail starts to shrink, and lungs develop, allowing them to breathe air instead of relying on gills. Eventually, the tadpoles transform into froglets.

6. Froglet Stage: Froglets are young frogs that have completed metamorphosis but are still small and have some characteristics of tadpoles. They have both hind and forelimbs, lungs for breathing air, and a smaller tail. Froglets continue to grow and develop until they reach adulthood.

7. Adult Frog: Once the froglets reach adulthood, they have fully developed limbs, lungs, and reproductive organs. They are capable of reproducing and continuing the life cycle of frogs.

It's important to note that the exact timing and duration of each stage can vary depending on the species of frog. Additionally, some frogs may have slightly different reproductive strategies, but the general sequence described above applies to most frogs.

I hope this information helps! Let me know if you have any further questions.