Answer:
For population increase two factors or ways are described which are birth or death, immigration and emigration.
The two ways a population can decrease is through mortality and emigration.
Explanation:
A population's increase is resolved by death, birth, immigration, and emigration. When a population's birthrate is higher than its death rate the population size, The population size is rises.
Also,The two factors responsible for the decrease in size of a population are emigration, which is the migration of an individual from a place. and mortality, which is the number of individual deaths in a population over a period of time.
B. inactive genes in dolphins
C. fossil footprints left by dinosaurs
D. remnants of bacteria colonies dating to 3.5 billion years ago
B. Earth is tidally locked, while the moon spins on its axis.
C. The moon is older than Earth by approximately 300 million years.
D. Earth and the moon have nearly the same mass.
Answer:
A
Explanation:
It is believed that the moon was formed shortly (relative time) after the earth was newly formed. This occurred in a massive planet-sized collision that ejected a huge chunk of the earth out into space. The chunk, still within earth gravitational reach, began orbiting the earth becoming the moon. Both earth and moon are slightly more than 4 billion years old.
Answer:
A. Earth and the moon are nearly the same age.
Explanation:
These hypotheses are consistent with the evidence that shows rock from the moon and the earth have nearly the same age and composition.
Answer:
Cenozoic era
Explanation:
The geological time scale consists of three eons: Archaean, Proterozoic and Phanerozoic. The Phanerozoic eon is divided into three era which are namely: Paleozoic, Mesozoic and Cenozoic era. Cenozoic era extends from “end-Cretaceous extinction” to the present day. It is dominated by mammals and is also called as the “age of mammals”.
Answer:
8. D
9. A
10. A
11. C
12. D
Explanation:
8. Natural selection works on variation that exists in the genes of organisms. Antelopes who have genetic variation that makes their legs more muscular are at an advantage because they can outrun predators. This increases the chance that they will reach reproductive age, and be able to pass this advantageous trait onto their offspring. Over time, this selection pressure makes the variant more common in a population.
9. Beneficial traits are those that give a selective advantage. This could be one that helps it outrun predators (like above), avoid illness and death, gives it a reproductive advantage (i.e. more attractive to mates), or makes it better able to digest certain foods, for example. The formation of cancer cells would be harmful for an organism, reducing its fitness and perhaps leading to death. The inability to reproduce would mean genetic info is not passed on to the next generation, and stopping the production of an essential protein would likely lead to death. However, resistance to a virus would help an organism avoid illness and death, improving fitness.
10. Genotypes are what organisms inherit from their parents, i.e. the genetic information that is passed on. However, the way in which different alleles interact and are expressed is the phenotype. If we take the above example, natural selection is acting on the phenotype of muscular legs. If an antelope had the muscular leg genotype but for some reason it was not being expressed (maybe another gene is interfering with it), then the antelope would not have a selective advantage, and natural selection could not be act on the trait.
11. A trait that better suits an organism to its environment will be selected for by natural selection. This is because that organism is more likely to survive due to the trait, giving it a selective advantage. Therefore, if a mutation arose making the giraffe more adapted to the environment, it would be positively selected for, and through evolution would become more common.
12. This is an example of selective breeding, which has been happening for generations. Farmers spot desirable traits, and cross horses with these traits in an attempt to enhance the trait or to ensure it is passed on to the next generation. This is not natural selection, because farmers are making it happen artificially. It is not cloning or recombinant DNA, which are terms scientists use for actually manipulating the DNA in the lab.