Biology Chapter 19 HW & Quiz - Human Evolution

Quiz

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Research into the evolution of skin color has resulted in a complete hypothesis that explains why skin color varies geographically. Which description is a result of this research?

-Melanin absorbs damaging UV light, which could serve as protection against folate destruction to those humans living in high-UV-light environments. -Both dark and light skin are linked to levels of global sunlight. -Light skin is an adaptation that helps humans produce vitamin D in sun-poor parts of the world. -Dark skin is an adaptation in high-UV-light areas that helps protect folate stores.

What are characteristics of mitochondrial DNA that made it a suitable choice for studying human evolutionary patterns?

-Mitochondrial DNA mutates at a fairly regular rate. -Mutations from mothers are passed to offspring without recombination with paternal mtDNA. -Individuals with nearly identical mtDNA sequences are more closely related.

Why is there so much variation in human skin coloration?

-Variation occurs because humans are found in areas that range from high-UV-light environments to low-UV-light environments. -Variation occurs because humans underwent natural selection, which resulted in traits that conferred advantages to humans becoming fixed in populations. -Variation occurs because skin coloration results in different advantages, depending on the levels of sun in the region. -Variation occurs because alleles that are harmful in one environmental context may be beneficial in another.

A person's skin tone is influenced by ________.

-the amount of sunlight to which a person is exposed, which temporarily causes the skin to increase melanin production -the amount of melanin present in the skin -the person's genetic ancestry and the types of alleles he or she carries

Hominids evolved under natural selection pressures, which selected for certain traits that conferred an advantage to individuals. Consider the following list of traits. Choose the answer that correctly orders the evolutionary pattern of hominid traits. 1. Hominids lost some of their body hair and gained more sweat glands. 2. Hominids evolved dark and hairless skin. 3. Hominids were covered in thick hair and had light skin.

3, 1, 2

Scientists used mitochondrial DNA to investigate patterns of human evolution. Which description is a result of this research?

All humans alive today are related to a single female ancestor.

Which of these is something found in the fossil record that has been used by scientists to understand human evolutionary patterns?

All of these are found in the fossil record and have been used by scientists to understand human evolution.

How are mitochondrial genes typically inherited?

An individual inherits their mitochondrial DNA from their mother.

There are many examples of species that were ancestral to or closely related to the ancestors of modern humans, Homo sapiens sapiens. The figure shows when several key human ancestors were alive. Label the figure with the names of the human ancestral species.

Australopithecus afarensis/ Australopithecus robustus/ Homo habilis/ Homo erectus/ Homo neanderthalensis

An extensive study of a hominid fossil dating from approximately 2 million years ago was published in 2013. Determine whether each of the features described is closer to the ancestral state or to the modern human state. -- The shoulder structure and very long arms suggest the ability to climb and perhaps hang or swing. -- The spine and other skeletal features suggest an upright stance. -- There is no opposable toe. -- The skull is very small.

Closer to the ancestral state. -- Closer to the modern human state. -- Closer to the modern human state. -- Closer to the ancestral state.

Which statement is a correct description of the relationship between UV light in the environment and how it affects humans?

In a high-UV-light environment, more melanin is likely to be produced.

Which statement is a tenet of the out of Africa hypothesis for the origin of modern humans?

Modern humans evolved in Africa and then migrated throughout the world, replacing earlier human populations.

Which statement is a way scientists used mitochondrial DNA to determine where humans first evolved and how they spread?

Scientists used the relatively regular rate of mtDNA mutations to determine how long it had been since groups diverged from one another.

Scientists have studied patterns of mitochondrial DNA to determine where humans first evolved and how they spread. Humans inherit their mitochondrial genes only from their mothers. Why aren't a father's mitochondrial genes passed to his offspring?

Sperm do not contribute their mitochondria to the zygote.

Which of the following is an accurate description of hominid evolution?

The last common ancestor of modern humans and great apes lived 13 million years ago.

Researchers have studied human genetic relatedness and the distribution of certain traits to infer patterns of human migration. Their studies show that humans who migrated northward from Africa had descendants with _______.

a greater risk of folate deficiency

Given its traits, where would you place this fossil on the lineage between the chimpanzee-human ancestor and modern humans? -- What genus is this fossil likely a member of?

between Australopithecus and early Homo -- Australopithecus

Scientists have found that ________.

genetic diversity decreased as early humans migrated away from Africa and founded new populations

Which of these is part of the hominid family?

gorillas/orangutans/humans/bonobos

Imagine a population of yellow beetles. Two beetles mate. Due to a DNA replication mistake during gamete production in one of the parents, the beetles' offspring are black. This increases the frequency of genes for black coloration in the population. *Which evolutionary process does this scenario describe?

mutation

The fossil remains of Ardipithecus ramidus showed that ________.

the ability to walk upright preceded the evolution of a larger brain

The darker the skin of a person, the more likely that some of that person's ancestors _______.

were from a geographical area closer to the equator