<span>Damming a river has a variety of effects on the freshwater ecosystem, more than just altering the flow from A to B. Dams create calm bodies of water, changing overall temperature regimes and sediment transport, leading to conditions which tend to favour generalist species. Loss of specialist species, particularly endemics, changes the community structure and leads to biotic homogenization. A dam will withhold sediment in the reservoir, not just decreasing the amount of substrate available to local freshwater species, but even impacting diadromous, estuarine and marine species much further downstream. The competition between resident species for food and breeding sites will increase as damming isolates populations, and perhaps more importantly, damming completely restricts migratory fish species. Isolation may lead to decreases in genetic diversity and therefore puts species at greater risk from disease. All of these effects may be exacerbated by changes in the surrounding land use. Overall, damming river flow will lead to both a loss of native species, but also an increase in exotic species which are more likely to become established in degraded habitats. For this reason, dams are one of the greatest global threats to freshwater biodiversity.</span>
Answer:
Eukaryotes are organisms made out of eukaryotic cells, cells with a membrane-bound nucleus and membrane-bound organelles.
Prokaryotes differ from eukaryotes in that their cells do not contain a membrane-bound nucleus that contains their DNA.
Explanation:
During the day, plants carry out photosynthesis releasing carbon dioxide. During the night, there isn't any sunlight so the plants carry out cellular respiration releasing oxygen.
Answer:
Dinosaurs are the extinct organisms that belong to the class reptilia. Dinosaurs are the most advanced and bulkier reptiles at the history time and they were overspecialized in their environment.
The dinosaurs extinct rapidly due to the change in the external conditions and the volcanic eruptions that occur at the dinosaurs time. The recent searcher claims that asteroid impact and massive volcanic eruption leads to the dinosaur extinction. The fossil evidence and the presence of the specific basalt and other chemicals are found in the volcanoes and in the asteroid.
