All GRE Subject Test: Biology Resources
Example Question #1 : Plant Evolution
Which is of the following is not an adaptation/modification that enabled plants to move from aquatic to terrestrial environments as they evolved?
Roots and root hairs
Thylakoid membranes are found within chloroplasts, which are used for photosynthesis. Plants found in both aquatic and terrestrial environments photosynthesize, so these membranes cannot be considered adaptations uniquely benefiting terrestrial plants.
Comparatively, cutin is a waxy coating found on various parts of plants that helps prevent water loss when exposed to air. Stomata are tiny openings in the epidermis of plants that allow for the exchange of carbon dioxide and oxygen while minimizing water loss. Roots and root hairs allow plants to absorb nutrients and water from the soil. Water loss was the primary challenge plants faced when moving from aquatic to terrestrial environments; cutin, stomata, roots, and root hairs all help terrestrial plants absorb and conserve water.
Example Question #1 : Evolutionary History
Which structures did not evolve after plants emerged onto land?
Cell walls were present in plant cells before the transition to land. Seeds, stomata, waxy cuticles, and vascular transport all evolved to reduce water loss and circulate water to all areas of the plant. Water loss and circulation were not an issue before the transition to land; plants were forced to adapt these traits in order to survive in a terrestrial environment.
Example Question #2 : Understanding Vascular And Avascular Plants
Which of the following is not an example of an advantage gained through the vascularization of plants?
Dominant sporophyte generation
Larger photosynthetic area
Extensive root and shoot systems
Swimming sperm is a feature of avascular and early vascular plants, who needed to remain in moist environments in order to retain water.
After gaining vascular systems, plants were able to circulate water and nutrients more efficiently, thus being able to grow larger, have more leaves, develop branched systems of roots and shoots to collect water and nutrients, and better dispersal of spores due to gains in size.
Example Question #3 : Plant Evolution
As plants moved from water to land, they developed structures and lifestyles better suited to life in their new environment. Which of the following is not an example of these adaptations?
Increase in vertical height
Decrease in rigidity
Decrease in rigidity
Plants developed more rigid structures to help maintain their growth on land as opposed to water.
Waxy cuticles developed to help reduce water loss/desiccation. Roots allowed plants greater access to water, as well as provided anchoring to the ground; this allowed plants to grow taller. Vascular tissue facilitated transport of water and nutrients to all parts of the plant. Stomata helped with gas exchange.