Although they both prevent successful interbreeding among members of different species,
isolating mechanisms prevent the formation of a zygote, whereas
isolating mechanisms prevent successful reproduction of a hybrid after successful fertilization has occurred.

Question

Although they both prevent successful interbreeding among members of different species, 
 isolating mechanisms prevent the formation of a zygote, whereas 
 isolating mechanisms prevent successful reproduction of a hybrid after successful fertilization has occurred.

BlackTom AI · Accepted Answer

The question presents a two-blank statement about isolating mechanisms and asks you to fill in the appropriate terms for each blank.

First blank (空白1): What type of isolating mechanism prevents the formation of a zygote? Prezygotic barriers act before fertilization and stop mating or fertilization from occurring, so they prevent a zygote from forming. Examples include temporal isolation (mating at different times), habitat isolation (different environments), behavioral isolation (different courtship), mechanical isolation (incompatible reproductive structures), and gametic isolation (gametes can’t fuse). Therefore, the correct fill for the first blank is prezygotic.

Second blank (空白2): What type of isolating mechanism prevents the successful reproduction of a hybrid after fertilization has occurred? Postzygotic barriers operate after fertilization, reducing the fitness of hybrids or preventing them from reproducing. Classic examples are reduced hybrid viability (hybrids die before reproducing), reduced hybrid fertility (hybrids are sterile, e.g., mules), and hybrid breakdown (hybrids are healthy at first but sterile or inviable in later generations). Hence, the correct fill for the second blank is postzygotic.

In summary, when describing barriers to reproductive isolation:
- Prezygotic barriers prevent zygote formation
- Postzygotic barriers prevent successful reproduction after fertilization
The two blanks should be filled as: prezygotic for the first, postzygotic for the second.

Although they both prevent successful interbreeding among members of different species, isolating mechanisms prevent the formation of a zygote, whereas isolating mechanisms prevent successful reproduction of a hybrid after successful fertilization has occurred.未知题型

类似问题

Crosses between female horses and male donkeys produce mules. Gene flow between the gene pools of horses and donkeys is prevented by I. hybrid sterility. II. a pre-zygotic isolating mechanism. III. a post-zygotic isolating mechanism.

Differences of bird songs between two closely related species of meadowlarks represent a mechanism for

Two species of a plant cannot interbreed, because their flowers differ in size and shape and require pollination by different species of bee. This is a/an ___ isolating mechanism.

Two species of a plant cannot interbreed, because their flowers differ in size and shape and require pollination by different species of bee. This is a/an ___ reproductive barrier.

Prezygotic isolating mechanisms are typically more common than postzygotic mechanisms. One explanation is that prezygotic mechanisms are less costly in terms of and , and so natural selection has favored them.

Reproductive isolating mechanisms fall into two main categories: isolating mechanisms and isolating mechanisms.

In some cases, species are defined by the ability of members to interbreed or the extent of isolation.

Mechanisms that prevent genetic exchange between members of different species and often play a role in plant and animal speciation are termed reproductive mechanisms.

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单