All of the above points are valid for fossils' contributions in understanding the process of evolution. They allow us to study the ancestry, we can see the homologous organs or structures, if fossils are well-preserved; different fossils can lead us to follow the cycles of the changes that occurred during macroevolutions, and fossils can be used to study different populations which had different body structures for surviving in different environmental conditions.
Answer:
A conserved set of cyclin-dependent protein kinases (Cdks) initiate or regulate events through phosphorylation of intracellular proteins, thus controlling cell cycle progression, terminal differentiation, and apoptosis. ...
Explanation:
Answer:
Answer:
THE GREAT SPERM RACE:
A sperm's race to fertilize an egg is not so easy. Out of about 250 million sperm ejaculated into the human vagina during intercourse, not more than one in a hundred will survive the Great race to the end due to the hurdles it has to face in the hostile, ACIDIC CHAMBER to the cervix (it has hundreds of tiny branching tunnels that can trap, crush and slowly kill sperm).
If ovulation is not occurring soon the sperm will "drown in a thick flow of cervical mucus
Answer:
Increase occur in skin diseases and decrease occurs in the Earth's average temperature.
Explanation:
If both Carbon Dioxide and Ozone levels began to decrease, increase occur in skin diseases and decrease occurs in the Earth's average temperature. The decrease in ozone levels allows more UV radiation to reach the Earth's surface which lead to various diseases such as skin cancer, cataracts, and weakened immune systems. The atmospheric carbondioxide gas is responsible for the increase of surface temperature by trapping reflected solar radiations so decrease in carbondioxide concentration will leads to lower surface temperature.
Explanation:
the top predator is removed from the delicate balance of any particular ecosystem, there may be disastrous effects for the other plants and animals that inhabit the environment.
When a top predator is removed from an ecosystem, a series knock-on effects are felt throughout all the levels in a food web, as each level is regulated by the one above it. This is known as a trophic cascade. The results of these trophic cascades can lead to an ecosystem being completely transformed. The impacts trickle down through each level, upsetting the ecological balance by altering numbers of different animal species, until the effects are finally felt by the vegetation
When a top predator is no longer present, populations of their herbivorous prey begin to boom. Without a top predator to regulate their numbers, these animals put a great deal of pressure on the existing vegetation that they require for food and can destroy large amounts of plant life, such as grasses and trees. This then causes further problems, such as soil erosion and loss of animal habitat. Eventually, humans are also impacted due to the resulting lack of soil fertility and clean water that depend on these plants.
Another problem involving the loss of vegetation is the competition that is created between herbivorous species. Competition between species for the remaining plant life is high and weaker species lose out to stronger ones, leading to the potential loss of weaker animals, as well as plant species. Increased competition, therefore, leads to a lack of biodiversity. In contrast, top predators often have varied diets, which means they can pursue a new food source if one is running low, preventing the first source from being eradicated completely. This is one of the ways that top predators are able to maintain biodiversity and the balance of an ecosystem.
The presence of a top predator also helps to maintain balance in an ecosystem by influencing the behaviour and movements of its prey through the fear of being caught. Animals that are prey to a top predator will move around in order to avoid it. This prevents plants and animals in any particular area of an ecosystem from being over-consumed, preserving food sources and habitats. In the absence of top predators, this regulation disappears, allowing certain areas of vegetation to be destroyed completely.
