The shoreline is one of the harshest and most changeable environments for living creatures. The changing tides shift the environment dramatically within a sub-daily cycle. Here, we can consider two typical shoreline organisms, and the changing environment they must endure. Within the rocky shore environment, an octopus would be within the shallow but open sea environment during high tide, and water temperature and salinity conditions would be fairly constant. During low tide, the octopus might become trapped in a rock pool. This environment is dramatically different. The water temperature and salinity might increase drastically with exposure to solar radiation. The octopus is also more vulnerable to predation by humans and other land animals. Within the sandy shore environment, sand clams would be actively positioned at the interface of the sand and water, and will be actively filtering sea water for detritus. During low tide, the sand would be exposed to the air, and the clams would burrow down into the sand so as to avoid dessication.
organisms are always in competition for resources such as food and water or simply just for space.
They are both used to benefits plants growth process.
Answer:
(A) speciation.
Explanation:
Shrinking of water bodies and development of deserts since the Pleistocene ice age produced new vacant niches that could be inhabited by organisms such as fishes. Production of new isolated streams, ponds, and springs allowed the fishes to occupy these new water bodies. Accumulation of genetic variations to become adapted to their new habitat resulted in the evolution of several new species of fishes with many different genetic traits. This represents speciation due to geographical isolation.
