Biology B Notes - Lesson 4

What are allopatric species?

species that are physically separated and live in different areas

Which of the following terms correctly describes a population that becomes divided into separate subpopulations that live in the same area?

sympatric

Provide an example of adaptive radiation.

the diversification of mammals that occurred after the extinction of the dinosaurs

What are some suspected causes of Earth's mass extinctions?

volcanic eruptions and the impact of large asteroids

Which of the following is an example of a monogenic trait?

widow's peak

Fill in the following Punnett square. https://cdstools.flipswitch.com/asset/media/924092 What should the empty box display based on these parents?

ww

How is a normal distribution illustrated, and what does each part of the illustration represent?

A bell curve graph illustrates a normal distribution. In a normal distribution, the middle of the bell curve represents the majority of the population, and either side of the curve represents the population that lies outside the majority.

Which of the following situations could result in divergent evolution in sympatric populations? Select all that apply.

A mutation during reproduction causes the chromosomes in a species of flowering plant to double, resulting in an individual with four sets of chromosomes. A mutation has resulted in some individuals of a plant species flowering early in the spring, while other members of the same species flower much later.

Explain why the following statement is false. A population consists of all individuals in one particular area.

A population is a group of individuals that breed with one another and share genes. If all individuals in one area are not able to breed with one another and share genes, then they do not constitute a population.

Which of the following is an example of a mass extinction?

An asteroid hits Earth and causes most of the planet's life to die out.

How can genetic mutations affect an organism's fitness level?

Genetic mutations can prevent an organism from reproducing or surviving. Mutations in one organism can affect future generations of that species if the offspring of the mutated organism inherits the genetic change.

Describe sympatric populations and how divergent evolution can occur in them.

If a population becomes fragmented into different breeding groups because of some sort of behavioral or reproductive barrier, such as a mutation causing a difference in reproductive behavior (a timing change in the flower production in plants, for example), then the groups will become reproductively isolated from each other even though they are still found in the same area. This is a sympatric population. Divergence can occur because of environmental differences that exist between the habitats of the two groups, causing different selective pressures on the two groups. Divergence can also result from the random accumulation of genetic mutations that become unique to each group.

Describe allopatric populations and how divergent evolution can occur in them.

If a population becomes fragmented into different groups because of some sort of geographic isolation or barrier, such as an emerging mountain range, a volcano, or the isolation of one or more members of a species on an island, then the groups are physically separated and can no longer interbreed. This is an allopatric population. Divergence can occur because of environmental differences that exist between the habitats of the two groups, causing different selective pressures on the two groups. Divergence can also result from the random accumulation of genetic mutations that become unique to each group.

Why is the production of new species by polyploidy more common in plants than in animals?

In animals, polyploidy often makes the organism sterile, but plants can still reproduce asexually or by self-fertilization if they are polyploid.

Explain the difference between convergent evolution and parallel evolution.

In parallel evolution, two ancestral species share a common trait. Both species evolve into new species that share a new and different trait. In convergent evolution, two very different ancestral species both give rise to new species, and the new species end up evolving the same new trait, making them appear more similar to each other than their ancestors were.

How did Mendel's work add to the study of evolution?

Mendel's work helped scientists understand how advantageous traits (both seen and unseen) could be passed down and how this could affect natural selection.

Why do variations of traits occur?

Some traits are controlled by one gene, and others are controlled by several genes. When several genes are involved in a trait, more alleles are involved, so more variation occurs.

Determine if the following statement is true or false. Allopatric species are two species or populations of the same species that live in separate geographic areas.

True

Determine if the following statement is true or false. Because gene inheritance was not fully understood during Darwin's time, he did not understand how advantageous traits were passed down.

True

Determine if the following statement is true or false. Being heterozygous for a gene may cause only the dominant allele to be expressed, but the recessive gene may be passed to offspring that express it.

True

Determine if the following statement is true or false. Relative frequency is the number of times an allele for a gene appears in a gene pool when compared to the number of times the other alleles for the same gene appear.

True

Determine if the following statement is true or false. The combined genes from all the members in a particular population form a gene pool.

True

Can a mutation that occurs in a body cell affect the fitness of an organism? Why or why not?

Yes, a mutation can affect the fitness of an individual organism. This is because the mutation may decrease its ability to survive and reproduce.

A monogenic trait is a trait that is controlled by _______.

a single gene

A type of divergent evolution in which a species can evolve into multiple new species in a relatively short amount of time is known as ____________ .

adaptive radiation

Read the following scenario. The seed from a small herbaceous flowering plant gets blown to an isolated island by the wind. There are few plants and no trees on the island. Over time, many new species evolve from this plant, quite a few of which are trees. What type of evolution is described in this scenario?

adaptive radiation

The diversification of mammals after the extinction of the dinosaurs is an example of _________.

adaptive radiation

Which of the following terms correctly describes a population that becomes divided into two geographically separate subpopulations?

allopatric

A predator-prey relationship, such as that between lions and zebras, is an example of ________.

coevolution

Read the following scenario. A flowering plant evolves such that the shape of its flower and nectar is suitable to attract moths, and the moth evolves such that its mouth parts can properly reach into the flower. What is the scenario an example of?

coevolution

The process in which two entirely different species evolve in response to each other is called _[blank]_.

coevolution

Which of the following would likely not trigger a mass extinction?

continental drift

Examine the following DNA sequences of two ancestral species, and the two new species that evolve from them, and then answer the following question. https://h2.flipswitch.com/images/2017/Edited/c410f40b-644c-4ea0-a5fc-2d862c35d9d0.png What type of evolutionary process occurred?

convergent evolution

Examine the following graph. https://cdstools.flipswitch.com/asset/media/448881 Which type of evolution does the graph illustrate?

convergent evolution

https://h2.flipswitch.com/images/2017/Edited/f696989f-9841-4cbc-b6ae-a9964c48798f.png Which type of evolution is illustrated by diagram C?

convergent evolution

Examine the following DNA sequences of two ancestral species, and the new species that evolved from them. Ancestor 1GGCTAGCTATATT Ancestor 2GGCTAGCTATATT New Species 1GGCTTGCTATATT New Species 2GGCTCGCTATATT What type of evolutionary process occurred?

divergent evolution

https://h2.flipswitch.com/images/2017/Edited/4185e89a-9857-4d39-a58a-68dc00cf1882.png Which type of evolution is illustrated by diagram B?

divergent evolution

Which of the following represent ways that a population could become isolated? Select all that apply.

emerging mountain range islands volcano

What are three ways in which scientists have studied events that happened during evolution?

examining fossil remains, examining the current distribution of species, examining DNA from various species

Give an example of a polygenic trait.

height in humans

Which of the following does not allow genetic variation to occur?

mitosis

What percentage of species that have lived on Earth are now extinct?

more than 99%

What could cause a population to become isolated without a physical barrier?

mutation

Study the following graph. https://cdstools.flipswitch.com/asset/media/915029 The bell curve shows what kind of pattern of distribution?

normal distribution

Study the graph. https://cdstools.flipswitch.com/asset/media/915029 What pattern of distribution is illustrated?

normal distribution

https://h2.flipswitch.com/images/2017/Edited/0e8ce07c-ff23-49b0-9dd5-212a9e1b1857.png Which type of evolution is illustrated by diagram A?

parallel evolution

Traits that are controlled by more than one gene, such as human height, are referred to as _________.

polygenic traits

A group of individuals that breed with one another and share genes make up a ________.

population

The study of evolution of biological populations from a genetic viewpoint is called __________.

population genetics

The number of times an allele for a gene appears in a gene pool when compared to the number of times the other alleles for the gene appear is called ________.

relative frequency

The paragraph below summarizes how genetic mutations occur. Fill in the blanks using the words from the word bank. chemicals mistake radiation replication sequence Genetic mutations occur when the DNA __________ of a gene changes. This happens when there is a __________ during DNA __________ or as a result of __________ or __________ in the environment.

sequence; mistake; replication; radiation; chemicals Genetic mutations occur when the DNA sequence of a gene changes. This happens when there is a mistake during DNA replication or as a result of radiation or chemicals in the environment.

During what process does gene shuffling occur?

sexual reproduction