Mastering Biology Chapter 14

Questions and Answers

Feathers either play a role, or may have played a role, in _____.

all of these

_____ is rapid speciation under conditions in which there is little competition.

Adaptive radiation

Mass extinctions create conditions that promote _____.

adaptive radiation

The appearance of an evolutionary novelty promotes _____.

adaptive radiation Signup and view all the answers

The different finch species found on the Galápagos Islands probably arose as a result of _____.

adaptive radiation Signup and view all the answers

Classifying Reproductive Barriers:

a = Prezygotic barriers b = Postzygotic barriers c = Behavioral isolation d = Mechanical isolation e = Temporal isolation f = Gametic isolation g = Reduced hybrid fertility h = Different ticks live on different host species i = One sea urchin's sperm cannot fertilize another species' eggs j = Lion-tiger hybrids don't live to reach maturity Signup and view all the answers

According to the ______ species concept, a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.

Biological Signup and view all the answers

The separation between species is maintained by _______ isolation, which prevents gene flow between species.

reproductive Signup and view all the answers

But in some cases, distinct species can occasionally interbreed, producing ________ offspring.

hybrid Signup and view all the answers

Alternatively, the _______ species concept identifies species based on physical traits or body form.

morphological Signup and view all the answers

This species concept can be applied to ________ species, and it is the way most of the 1.8 million named species have been identified.

asexual and extinct Signup and view all the answers

In the _______ species concept, species are defined by their niche--the role they play in the environment.

ecological Signup and view all the answers

The ________ species concept defines species as the smallest group of individuals that share a common ancestor and form one branch on the tree of life.

phylogenetic Signup and view all the answers

In ________, a population isolated by a geographic barrier becomes a new species as it accumulates changes by natural selection or genetic drift.

allopatric speciation Signup and view all the answers

In ________, a new species may arise as mating and gene flow are reduced between populations that share the same area.

sympatric speciation Signup and view all the answers

Many plant species have formed by _______, in which accidents in cell division result in extra sets of chromosomes.

polyploid speciation Signup and view all the answers

Both allopatric speciation and sympatric speciation depend on the establishment of ________, which prevent(s) gene flow between a new species and its parent species.

reproductive barriers Signup and view all the answers

________ occur(s) when a species gives rise to many new species after colonizing a region with diverse habitats.

Adaptive radiation Signup and view all the answers

Connecting the Concepts: Species and Speciation:

a = Biological b = Morphological c = Allopatric speciation d = Sympatric speciation e = Hybrid zones f = Reproductive isolation g = Reinforcement Signup and view all the answers

Humans are diploid and have 46 chromosomes. How many sets of chromosomes are found in each human gamete?

1 Signup and view all the answers

Humans are diploid and have 46 chromosomes. How many chromosomes are found in each human gamete?

23 Signup and view all the answers

_____ is the process by which haploid gametes form a diploid zygote.

Fertilization Signup and view all the answers

A particular diploid plant species has 48 chromosomes, or two sets. A mutation occurs and gametes with 48 chromosomes are produced. If self-fertilization occurs, the zygote will have _____ set(s) of chromosomes.

4 Signup and view all the answers

Which of these terms applies to an organism with extra sets of chromosomes?

polyploid Signup and view all the answers

Mutant tetraploid plants _____.

are unable to interbreed with a diploid plant Signup and view all the answers

Most polyploid plants arise as a result of _____.

hybridization Signup and view all the answers

How do the skulls of adult chimpanzees and humans differ?

Adult chimpanzees have heavier brow ridges. Signup and view all the answers

The differences between chimpanzee and human observed in these animations is attributable to differences in ____.

allometric growth Signup and view all the answers

What accounts for human infants having large heads on small bodies?

allometric growth Signup and view all the answers

Variations in allometric growth patterns demonstrate how _____.

relatively small genetic changes can have a major impact on phenotype Signup and view all the answers

Which of these is a difference between the skull of an adult chimpanzee and the skull of an adult human?

All of these are differences between adult chimpanzee and adult human skulls. Signup and view all the answers

Which of the following statements about reinforcement is true?

Reinforcement is a type of natural selection. Signup and view all the answers

A subset of a population of birds leaves its habitat and colonizes a nearby island. After many generations, the island sinks and the population of birds living on the island returns to its original habitat. Which of the following statements most accurately describes the two bird populations?

The birds were separated by dispersal. Signup and view all the answers

A biologist spends her summer break collecting frogs from a remote jungle in Peru. She discovers two distinct color forms that could be variants of a single species or two different species. What would be the most direct test of their species status under the biological species concept?

Observe mating in the natural environment of the two groups. If the two forms do not mate with each other, they are different species. Signup and view all the answers

In _____ isolation, it is physically impossible for two species to mate with each other, often because their genitalia do not fit together properly.

mechanical Signup and view all the answers

Eastern and western spotted skunks breed at different times of the year. Therefore, they are prevented from interbreeding by _____ isolation.

temporal Signup and view all the answers

The process of speciation starts with a single species. It often involves the following steps: (1) two populations become physically separated from one another by a barrier to dispersal and stop exchanging genes; (2) the populations experience independent evolutionary changes; (3) changes in one or both populations result in the development of reproductive isolating mechanisms that prevent interbreeding; further changes in geography may bring the groups back into contact. When do you officially have two separate species?

step 3 Signup and view all the answers

Darwin thought that significant evolution was much too slow to be witnessed in a human lifetime. Recent experiments by biologists have _____.

shown that some populations can evolve quite rapidly, with important changes occurring over several generations in the laboratory Signup and view all the answers

Of the 59 matings in the experimental groups, how many were between like-adapted flies (flies adapted to the same medium)?

42 Signup and view all the answers

Which of the following statements is best supported by the data on matings in the experimental groups?

The starch-adapted flies and maltose-adapted flies are not different species, but a reproductive barrier is forming between the populations. Signup and view all the answers

Which of the following statements is supported by the data from the control group matings?

Flies were about as likely to mate with flies from different starch-adapted populations as with flies from their own starch-adapted population. Signup and view all the answers

A similar control experiment was performed with flies adapted to maltose, and similar results were obtained. What were these control experiments testing?

These control experiments tested whether flies were more likely to choose mates from their own population than from another population adapted to the same medium. Signup and view all the answers

Current best estimates suggest that life has been on Earth for how long?

3.5 billion years Signup and view all the answers

If life exists or originated on another planet, most scientists today believe that it is which of the following planets?

Mars Signup and view all the answers

Which of the following is true regarding current scientific thought?

RNA originated before DNA. Signup and view all the answers

You discover a new means of energy transfer by organisms living in hydrothermal vents in the ocean. Who is most likely to be interested in funding your research?

Everett Shock Signup and view all the answers

Which of the following scientists is closest to creating life?

J. Craig Venter Signup and view all the answers

According to most paleoanthropologists, which of the following is true?

When modern humans arose, archaic humans disappeared in Africa. Signup and view all the answers

If your pituitary gland isn't functioning properly, which of the following will be affected?

reproduction and growth Signup and view all the answers

You are a paleoanthropologist studying Neanderthals. Where should you look for their fossils?

Europe Signup and view all the answers

What do paleoanthropologists generally believe about genetic findings?

Genetic findings need corresponding fossil evidence to be true. Signup and view all the answers

How do genomes of species change?

By mutations in DNA. Signup and view all the answers

Study Notes

Evolution and Speciation

Feathers have various roles, possibly in thermoregulation, display, and flight.
Adaptive radiation occurs rapidly in low-competition environments, often during mass extinctions and after the appearance of evolutionary novelties.
The Galápagos finches exemplify adaptive radiation, having evolved differently due to varying ecological niches.

Reproductive Barriers

Reproductive barriers are classified as prezygotic (before fertilization) and postzygotic (after fertilization).
Examples include:
- Behavioral isolation: Differences in mating rituals prevent interbreeding.
- Mechanical isolation: Physical reproductive parts are incompatible.
- Temporal isolation: Species breed at different times.
- Gametic isolation: Sperm and eggs of different species cannot fuse.
- Reduced hybrid fertility: Hybrids are often sterile or have lower fitness.

Species Concepts

Biological species concept: Defines species based on reproductive isolation and potential to produce viable offspring.
Morphological species concept: Identifies species by physical traits, applicable to both extinct and asexual species.
Ecological species concept: Defines species through their ecological niche.
Phylogenetic species concept: Defines species as groups sharing a common ancestor.

Speciation Mechanisms

Allopatric speciation: Occurs when populations are geographically isolated, leading to genetic divergence.
Sympatric speciation: New species arise in overlapping geographic areas, often due to behavioral changes.
Polyploid speciation: Common in plants, results from errors in cell division leading to extra chromosome sets.

Chromosomal Insights

Humans are diploid with 46 chromosomes; gametes contain 23 chromosomes.
Polyploidy in plants often results from hybridization, creating organisms with extra chromosome sets.

Developmental Biology

Allometric growth explains the size difference between human infants and adults, illustrating how small genetic changes can lead to significant phenotypic variation.
Adult chimpanzees have prominent brow ridges compared to humans, reflecting allometric differences.

Reinforcement and Isolation

Reinforcement strengthens reproductive barriers, facilitating natural selection.
The process of speciation involves physical separation, independent evolutionary changes, and the development of reproductive isolating mechanisms.

Current Scientific Concepts

Life on Earth has existed for approximately 3.5 billion years, with Mars being a likely candidate for extraterrestrial life origins.
RNA is considered to precede DNA in evolutionary history.

Paleoanthropology Insights

When modern humans arose, archaic humans likely vanished in Africa.
Neanderthal fossils can predominantly be found in Europe, supporting genetic findings that require fossil evidence for validation.

Genetic Changes

Species’ genomes change through mutations, affecting their evolutionary trajectory.

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Test your knowledge with flashcards covering essential concepts from Chapter 14 of Mastering Biology. This chapter focuses on evolutionary biology, including speciation and the role of mass extinctions in shaping biodiversity. Perfect for students looking to reinforce their understanding of these fundamental topics.