The red-legged frog breeds in ephemeral ponds from January through March. Its relative, the bullfrog, breeds in permanent ponds from late March through May. There are two pre-mating isolation mechanism at play here,
1. Ecological isolation: The habitats are different, hence the individuals of both the species do not meet. Ephemeral ponds are temporary ponds that develop during rainy days, while the permanent ponds are full of water throughout the year.
2. Temporal isolation: The time of mating is different for both the species to avoid contact between the individuals of closely related species. Red-legged frogs mate in January to March slot and the bullfrog in the March to May slot.
Gymnosperms are no longer restricted to moist environments, as are ferns and mosses because they have evolved to produce non-flagellated pollens that do not require water or moisture to reach the egg whereas ferns and mosses have flagellated sperm that needs moisture to swim towards the egg.
Another major evolutionary adaption in gymnosperms is the production of seeds instead of spores since seeds contain their own nutrition in the form of endosperm, seeds can travel large distances through wind or animals and can germinate when they find suitable conditions. Seeds can remain dormant for several years whereas spores have a shorter lifespan.
To learn more about endosperm here
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Answer:
<u>Isotonic</u>
Explanation:
If the solute concentration of the cell and that of its surrounding medium are the same there will be no net flow of water in either directions. In this case, the external solution is said to be isotonic to the cell.
Both the cytoplasm concentration and the glucose in the test tube are the same.
