Science 2
Scientists looked at the effects of a new invasive predator in the jungles of Madagascar. Looking at the image of Lemur fur color, describe what has happened to the lemur fur color over time.
For whatever reason, nature is not kind to white lemurs. The directional selection is caused by a new predator that only eats white or light colored lemurs. The selection moves in a decided way against all the lightest colored lemurs. Over time, the predator kills more of the light colored lemurs meaning they don't survive long enough to pass on their trait to offspring. So over time the lemur population evolves to have darker fur color.
A genetic mutation causes a newt to have faster reflexes. After many generations, most of the newt population has the reflex mutation. What most likely caused this change?
Newts with the mutation are better able to survive and reproduce than newts without the mutation.
A population of grasshoppers in the Kansas prairie has two color phenotypes, green and brown. Typically, the prairie receives adequate water to maintain healthy, green grass. Assume a bird that eats grasshoppers moves into the prairie. How will this affect natural selection of the grasshoppers?
The brown grasshoppers should be more easily seen by the predator and decrease the number of brown grasshoppers in the population.
There are two different colors of peppered moths, light colored wings and pure black wings are an example of this. The pure black moths are often found in areas with widespread air pollution. The light colored moths are found in clean air habitats. Write an explanation that explains why the moths are different colors
1.They have developed different colors because of their habitats. 2. Genetic variations of traits in a population increase some individuals' probability of surviving and reproducing in a specific environment. 3. Pure black moths are better hidden in dark polluted areas, while black and white moths are better hidden in clean wooded areas.
Define adaptation
A genetic characteristic that allows an organism to survive and reproduce.
natural selection
A process by which organisms with favorable traits produce more successful offspring than organisms with less favorable traits, causing the favorable traits to become more common in the population.
What determines which traits will be passed on to the next generation in the greatest frequency?
The fit of the trait to the environment.
Elephants are large herbivores native to Africa and India. They have few natural predators, but have suffered tremendous losses to human hunters. Of chief value to poachers are the elephants' tusks. The tusk is essentially an elongated tooth and is used to dig, to remove bark from trees, and as a weapon of defense. Those with the largest tusks are most attractive to the poachers. In India, almost half of all elephants are born without tusks. This percentage is likely on the rise due to the selection pressure of the hunters. Which trait of elephants has changed over many generations?
The length/size of the tusks.
What is the meaning of genetic variation?
The reproductive process involving two parents whose genetic material is combined to produce a new organism different from themselves.
Why are advantageous traits more likely to be passed onto offspring?
They are more likely to survive and reproduce.
Bacteria are single-celled organisms with very fast reproductive rates. Most are either harmless or beneficial to humans, but there are those that cause disease. One example is Staphylococcus aureas, whose infections are commonly called staph infections. These bacteria live on the skin of most people and are generally harmless. When they penetrate the skin and enter deep tissue, however, they can cause serious medical problems. These infections happen most often in the hospital, during surgery for example. Antibiotics have long been used to kill bacteria that are causing infections. A person infection with S. aureas might have billions of the bacteria throughout his or her body. Many of these bacteria have slightly different DNA codes that affect their reproduction rate, severity of infection symptoms, and susceptibility to antibiotics. When antibiotics are given, only those with genes to resist the antibiotic survive and reproduce. Over time, we have seen an increase in the number of bacteria that are resistant to antibiotics. Methicillin resistant S. aureas (MRSA) and vancomycin-resistant S. aureas (VRSA) are just 2 examples of these new "superbugs." In order for natural selection to produce ¨superbugs¨, what must have been true about the evolutionary history of bacteria?
In order for natural selection to have produced the superbugs, the bacteria must have showed variation within the species in every generation.
Polar bears are large predators that live in the extreme northern regions. They hunt for seals using ice platforms as a starting point. Polar bears are well adapted to their cold environments. They have large bodies, thick fur, and layers of fat to protect them from the cold. They are able swimmers, but cannot out-maneuver a seal in open water. They rely on the ice shelves to give them an advantage. Their white coats allow them to remain camouflaged in the snow and ice. Currently, worldwide increases in temperature are causing the ice shelves to disappear. Polar bears now compete for fewer of these hunting stations and, as a result, fewer available prey animals. Over time, a species of polar bears living in this environment may evolve polar bears that are good swimmers. Describe how natural selection creates this adaptation.
Polar bears with slightly better swimming abilities have a survival advantage. Over time, polar bears with this trait will be better adapted to survive in the increases temperatures.
Animals in dark cold environments are specifically adapted to that habitat. What contributed to the selection of these adaptations?
Some adaptations over time have offered survival advantages in the cold dark environment, so the organisms possessing these traits were survived better and passed their adaptation to the next generation.