Darwins Theory

Which statement describes natural selection? It is the primary mechanism for evolution. It must act on structural traits. It acts to cause overpopulation. It causes learned skills to become heritable traits.

It is the primary mechanism for evolution.

What is natural selection? a process that selects variations that help with survival and that spreads the variations to more offspring a process through which nature selects an individual within a population for extinction the difference in heritable traits within a population the process of nature that causes random variations to appear in the offspring of every generation

a process that selects variations that help with survival and that spreads the variations to more offspring

Charles Darwin observed a unique beak size and shape in the finch population of each of the Galapagos Islands that he visited. mc003-1.jpg Which is the most likely cause of the observed variation? differences in the climate among the islands competition among individuals for available food sources competition among individuals for desirable mates differences in egg size among the populations

competition among individuals for available food sources

Natural selection is a process by which organisms that are better adapted to their environment tend to increase in size. migrate. evolve new traits. survive.

survive.

A person with a genotype of HbSS has sickle cell disease. A person with a genotype of HbAS allele carries the sickle cell trait. A person with a genotype of HbAA does not have sickle cell disease and does not carry the trait. The Punnett square shows the genotype of two people carrying the sickle cell trait. Hb A S A AA AS S AS SS What are the chances that their offspring will have sickle cell anemia? 0% 25% 50% 100%

25%

Scientific investigations often lead to the formulation of new scientific questions. The observations Charles Darwin made during his time aboard the H.M.S. Beagle prompted him to ask which question? Do living organisms change over time and, if so, how? Are the finches of the Galapagos Islands the same as those on the mainland? Can selective breeding occur in nature? Can the accumulation of gradual changes in a population lead to a new species over time?

Do living organisms change over time and, if so, how?

Which best describes the relationship between evolution and natural selection? Natural selection leads to evolution. Evolution leads to natural selection. Natural selection is the same as evolution. Evolution and natural selection are not related.

Natural selection leads to evolution.

During a trip to the Galapagos Islands, which observation led Charles Darwin to suspect that organisms change over time? Island finches were able to breed with mainland species. Island finches resembled mainland finches, but were not the same species. Island finches resembled extinct species from other islands around the world. Island finches did not have beaks of the same size and shape.

Island finches resembled mainland finches, but were not the same species.

What is the best description of an organism that is fit for natural selection? The organism is physically stronger than competing organisms. The organism is physically stronger than organisms of a different species. The organism is better able to survive and pass on traits to offspring than competing organisms. The organism is a member of a population in which every member survives without competing.

The organism is better able to survive and pass on traits to offspring than competing organisms.

Which statement would least likely be used to describe variation? Variations are inherited differences between individuals of the same species. Variations that decrease reproductive success are more likely to be passed on. Variations may result in changes to an entire population after many generations. Variations provide some individuals with an advantage.

Variations that decrease reproductive success are more likely to be passed on.

The map shows the allele frequency of sickled hemoglobin (HbS) and malaria endemicity in Africa. mc027-1.jpg Which statement best explains the relationship between HbS allele frequency and malaria endemicity in Africa? When an area is malaria free, the HbS allele frequency is between 0 and 2.02. When an area is holoendemic, the HbS allele frequency is between 0.52 and 4.04. When an area is malaria free, the HbS allele frequency is between 12.64 and 18.18. When an area is holoendemic, the HbS allele frequency is between 0 and 0.51.

When an area is malaria free, the HbS allele frequency is between 0 and 2.02.

According to the concept of "survival of the fittest," if a population of birds eats worms that they find deep under ground by using their beaks, which members of the bird population would be more fit? birds that have flatter beaks birds that have longer beaks birds that have wider beaks birds that have brighter beaks

birds that have longer beaks

Consider this image of a gazelle. mc016-1.jpg Which of the gazelle's naturally selected traits is shown in this picture to be an evolutionary advantage? feeding only at certain times of the day coat color for blending in with dry grass specialized gut due to a diet of grasses specific gender roles to diminish predation

coat color for blending in with dry grass

Which would least likely be a cause of natural selection? adaptation evolution overpopulation variation

evolution

A frog lays thousands of eggs because many eggs die. This behavior is an example of __________________. competition overpopulation variation in a population survival of the fittest

overpopulation

Veronica wrote Charles Darwin's main points on the board, but she made a mistake in one point. 1. Since more offspring are produced than an environment can support, organisms within a population must compete for resources to survive. 2. Due to variations within the population, some competitors will be better equipped for survival than others. 3. The best-equipped organisms will survive and will produce well-equipped offspring. 4. Variations that help with survival will be passed on to future generations and will rapidly change the whole population. Which point is flawed as written above? point 1 point 2 point 3 point 4

point 4