Question

РЕШИТЕ ПОЖАЛУЙСТА 1) Почему у всех водяных растений мягкие, гнущиеся стебли? 2) Почему на суше нет таких гигантских живых существ, как киты?

Answer 1

Ответ:

Объяснение:

1) Чтобы удержаться водяным растениям (лилиям, кувшинкам и др) в вертикальном положении  в воде, не нужно иметь твердые стволы или упругие стебли, как на пов-сти земли. Это объясняется тем, что их вес в воде уменьшается на величину архимедовой силы.

2) На поверхности моря или океана их вес уменьшается на величину арх. силы, она становятся значительно легче, да и избегают тем самым влияния на суше атмосф. давления. Они могли   быть просто раздавлены атмосферой.  Наверное, такие "тяжеловесы" не смогли бы передвигаться на суше.

Answer 2

Why do all aquatic plants have soft, flexible stems?

Aquatic plants have soft, flexible stems for several reasons:

1. Adaptation to water movement: Aquatic environments are characterized by water currents and waves. Soft, flexible stems allow aquatic plants to withstand these movements without breaking or being uprooted. The flexibility of their stems helps them absorb and dissipate the energy from water movement, reducing the risk of damage.

2. Buoyancy: Aquatic plants need to stay afloat in water. Soft, flexible stems help them maintain buoyancy by reducing their overall weight. This allows them to float near the water's surface, where they can access sunlight for photosynthesis.

3. Nutrient absorption: Aquatic plants obtain nutrients from the water in which they grow. Soft, flexible stems increase the surface area available for nutrient absorption. The increased surface area allows for more efficient nutrient uptake, enabling the plants to thrive in their aquatic habitat.

4. Growth and reproduction: Soft, flexible stems also facilitate the growth and reproduction of aquatic plants. They allow for easy bending and movement, enabling the plants to reach towards light sources and disperse their seeds or spores more effectively.

Why aren't there giant creatures like whales on land?

The absence of giant creatures like whales on land can be attributed to several factors:

1. Physical constraints: The size of land-dwelling organisms is limited by the physical constraints of terrestrial environments. On land, gravity exerts a significant force, making it more challenging for large creatures to support their weight and move efficiently. The structural limitations of land-based locomotion, such as the need for limbs and a solid skeletal system, restrict the size of terrestrial organisms.

2. Energy requirements: Large organisms require a substantial amount of energy to sustain their metabolic needs. Aquatic environments, such as the ocean, provide a more abundant and energy-rich food supply compared to terrestrial ecosystems. The availability of high-energy food sources in the ocean allows marine creatures like whales to grow to enormous sizes. In contrast, the limited resources and competition for food on land make it difficult for terrestrial organisms to reach such colossal sizes.

3. Evolutionary history: The evolutionary history of life on Earth has shaped the diversity and size of organisms in different environments. Whales and other marine mammals have evolved in aquatic environments over millions of years, adapting to the unique challenges and opportunities presented by the ocean. Land-dwelling organisms, on the other hand, have evolved in terrestrial environments, where different selective pressures have influenced their size and morphology.

It's important to note that while there are no land-dwelling creatures as large as whales, there are still large terrestrial animals, such as elephants and giraffes, that have adapted to life on land. These animals have evolved specific adaptations to cope with the challenges of terrestrial environments and have reached sizes that are suitable for their ecological niche.