Q38.1-3CC. - Campbell Biology

Question

Does the life cycle of humans have any structures analogous to plant gametophytes? Explain your answer. (See Figures 13.5 and 13.6.)

 

Step-by-Step Solution

Answer

Animal life cycles do not have the same structure as plant gametophytes. As in mammals, there is no gametophyte equivalent. Animals do not have a multicellular haploid stage or phase in their gametic life cycle.

Step 1: Life cycle

During an organism's life, it goes through a series of changes known as the life cycle. A mortal life begins with birth and ends with death. The cycle starts with creation, continues through dissolution, and includes innumerable births and deaths.

Step 2: Analogous structure

Structures with similar functions but distinct evolutionary histories are analogous. Convergent evolution occurs when related structures are adapted to perform similar roles. This structure has a superficial resemblance. Different stages of development have comparable structures.

Step 3: Gametophytes

A gametophyte is a structure or phase of a multicellular organism with only one pair of chromosomes. A gametophyte creates either male or female gametes during mitosis (or both). Male and female gametes join to produce a diploid zygote through recurrent mitotic cell divisions.

Meiosis does not form sex cells in gametophytes, unlike mammals and other organisms that reproduce sexually. A gametophyte organism is made up of haploid cells, which have just one copy of each chromosome.