The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
Answer:
The correct match is given below:
Explanation:
- A flower containing a pistil, stamen, calyx, and corolla – Complete flower. When a flower consists of essential whorls pistil and stamen and accessory whorls calyx and corolla, the flower is said to be complete.
- The collective term for the petals of a flower- Corolla. The corolla is a accessory whorl which consist s of its unit called petal.
- It has pistils, but no stamens - Female flower. A flower with only pistil is called unisexual pistillate flower.
- A stalk which supports the anther – Filament. A typical stamen consists of an anther, connective and a filament.
- A flower that lacks one or more of the following parts: pistil, stamen, calyx, or corolla corolla.—Incomplete flower. A flower which lacks any of the essential or accessory whorl is called incomplete flower.
- A flower that has male parts only – Male flower. A flower with only stamen is called unisexual staminate flower.
- A spore produced by meiosis – Meiospores. Spores can produced by mitosis or meiosis. If it is produced as a result of mitosis it is said to be mitospores.
An explanation of how the natural world works.
Stressor due it comes from an external condition or event.
