Answer:
The coral reefs of the Caribbean are thought to be under threat
Explanation:
Overfishing threatens over 60 percent of Caribbean coral reefs. Declines in coral cover and increases in algal cover have been observed across the region. This analysis identified about one-third of Caribbean reefs at high threat from overfishing pressure and about 30 percent at medium threat.
Genetic drift is a process in which allele frequencies within a population change by chance alone as a result of sampling error from generation to generation. Genetic drift is a random process that can lead to large changes in populations over a short period of time.
Contour lines do not cross each other because of the variance in elevation between the lines. H<span>owever, an instance where two </span>contour lines<span> intersect occurs when the elevations are simultaneously </span>crossed<span> at an identical point through a vertical ledge.</span><span>
Hope this helps!
-Payshence xoxo</span>
PYRAMID OF NUMBERS- shows the number of each organism at the different trophic levels (feeding levels ie. producers consumers and decomposers) in a food web.
PYRAMID OF BIOMASS- The biomass of the members of the food chain present at any one time.Pyramid of biomass indicates decrease of biomass in each tropical level from base to apex.
Answer:
Preadaptations like tegument and body segmentation could have been used by insects and millipedes to survive in terrestrial habitats.
Explanation:
As crustaceans, millipedes and insects have a protective, hard tegument, which surface is frequently smooth. Some groups can also present spines, bristles, or tubercles. The tegument protects the animals against harmful stimuli of different nature, such as mechanic, thermal, chemical, etc. It is also an effective barrier against pathogen microorganisms and excessive dehydration. In groups like crustaceans and insects, as the external layer gets hard, the tegument constitutes an important support organ. It is composed of a simple, cubic epithelium called hypodermis, and secretes exoskeleton, which is composed of chitin and can also be shaped by calcareous impregnations. Chitin is an impermeable, light y hard substance, that allows life on land without dehydration. Segmentation (repetition of identical anatomical units) is another characteristic in these groups that have helped to domain terrestrial habitats. It seems like segmentation is highly advantageous from an evolution point of view because it is much easier to adapt each segment separately to environmental pressures, responding to different necessities, than adapting the whole body to it, developing a new organ for each necessity. Also, it is a strategy to defend themselves from predators by rolling up.
