Biology 101 Flashcards

Questions and Answers

What type of selection favors a midsized body?

Stabilizing selection

What does directional selection do?

Eliminates one extreme phenotype

What type of selection eliminates intermediate phenotypes?

Disruptive selection

The intermediate phenotype is favored in _____ selection.

stabilizing Signup and view all the answers

What is sickle-cell disease?

A recessive blood disorder Signup and view all the answers

Which of the following is an advantage of being heterozygous for sickle-cell disease?

Resistance to malaria Signup and view all the answers

What does industrial melanism refer to?

The increase in frequency of the dark phenotype due to pollution Signup and view all the answers

According to the biological species concept, a species is comprised of groups that are reproductively isolated. True or False?

True Signup and view all the answers

Match the following reproductive isolating mechanisms with their type:

Mechanical isolation = Prezygotic Hybrid inviability = Postzygotic Behavioral isolation = Prezygotic Hybrid sterility = Postzygotic Signup and view all the answers

Genetic drift is a random process.

True Signup and view all the answers

What major component was reconstructed in the Miller-Urey experiment?

An oxygen-free atmosphere Signup and view all the answers

What was suspected to be the first macromolecule that formed when cells first arose?

RNA Signup and view all the answers

Which gas would likely be excluded from Earth's early atmosphere?

Oxygen Signup and view all the answers

The main problem with the Miller-Urey experiment was that it didn't include the role of the ozone layer.

True Signup and view all the answers

What is the simplest and most abundant form of life on Earth today?

Prokaryote Signup and view all the answers

What do some bacteria use to swim?

Flagella Signup and view all the answers

Which process is exclusive to prokaryotes and not found in eukaryotes?

Binary fission Signup and view all the answers

Viruses consist of a core segment of DNA or RNA surrounded by a _____ coat.

protein Signup and view all the answers

Viruses contain _____ as the form of genetic material.

either RNA or DNA Signup and view all the answers

All viruses have an envelope around their capsid.

False Signup and view all the answers

Where did the COVID-19 virus most likely originate?

Bat Signup and view all the answers

Viruses that can infect bacterial cells are called?

Bacteriophages Signup and view all the answers

During bacterial conjugation, plasmid replication occurs in _____ the donor and recipient.

both Signup and view all the answers

The pilus is found on both the donor and recipient cells.

False Signup and view all the answers

Plasmids are small circles of DNA outside the main bacterial chromosome.

True Signup and view all the answers

Label the essential components of an animal virus.

RNA, Capsid, Envelope Protein, Envelope Signup and view all the answers

What do viral spikes do?

Attach specifically to host cell receptors Signup and view all the answers

In viral entry by endocytosis, what happens?

Host plasma membrane surrounds the whole virion and forms a vesicle. Signup and view all the answers

After the virus is released from the vesicle into the host cell cytoplasm, what happens next?

The capsid protein is removed. Signup and view all the answers

Under harsh environmental conditions, some bacteria are able to form thick-walled _____ to protect their DNA.

endospores Signup and view all the answers

What virus was responsible for killing approximately 100 million people between 1918 and 1919?

Influenza Signup and view all the answers

Complete the following statements about the characteristics of viruses: 1) ___ nucleic acid; 2) _ protein; 3) _ chemical; 4) _ cellular; 5) ___ reproduce.

1 nucleic acid; 2 protein; 3 chemical; 4 cellular; 5 reproduce Signup and view all the answers

Earth's early atmosphere contained hydrogen-rich gases like hydrogen sulfide, _____, and methane.

ammonia Signup and view all the answers

Scientists propose that early Earth’s energy sources could have driven chemical reactions that formed _____ molecules.

organic Signup and view all the answers

What is the term used to describe the gases released from volcanoes under the sea?

Bubbles Signup and view all the answers

What type of organisms do Archaea and Bacteria both consist of?

Prokaryotic Signup and view all the answers

Prokaryotic cells lack a _ and have a plasma membrane surrounded by a _ wall.

nucleus; cell Signup and view all the answers

Select all of the ways prokaryotes are important for humans and ecosystems.

Maintain genetic diversity of crop plants Signup and view all the answers

The filament of the bacterial flagellum extends out of the cell.

True Signup and view all the answers

The movement of the filament of the flagellum is a rotation that causes bacteria to _____ as it moves.

Spin forward and backward Signup and view all the answers

Prokaryotic organisms can reproduce asexually by _____, in which the DNA replicates.

binary fission Signup and view all the answers

What is the process called when bacteria exchange genetic information through a pilus?

Conjugation Signup and view all the answers

When faced with unfavorable conditions, some bacteria form thick-walled _____ to protect their DNA.

endospores Signup and view all the answers

Give an example of an origin of an emerging viral disease.

A virus passes from pigs to humans Signup and view all the answers

In 1859, naturalist _________ suggested an explanation for why evolution occurs.

Charles Darwin Signup and view all the answers

Darwin's evidence that evolution occurs includes which of the following? (Select all that apply)

All of the answer choices are correct Signup and view all the answers

Darwin better understood the mechanism for natural selection after he read a book by _________ on the rate of growth of populations.

Thomas Malthus Signup and view all the answers

Sizes of natural populations remain relatively stable over time because _________ limits population numbers.

death Signup and view all the answers

Darwin's main principle of natural selection was that every organism has the potential to produce more offspring than can survive, and those individuals that are better suited to their environment are more likely to survive.

True Signup and view all the answers

The final stimulus that convinced Darwin to publish his findings came from a young English naturalist, _________, who had come to the same conclusion as Darwin.

Alfred Russell Wallace Signup and view all the answers

Darwin's finches proved that beak sizes were the result of _________.

natural selection Signup and view all the answers

The notion that more distantly related organisms should have accumulated a greater number of evolutionary differences is best illustrated using _________.

DNA analysis Signup and view all the answers

The fossil record indicates that whales evolved from _________.

hoofed mammals Signup and view all the answers

Analogous structures are those similar in organisms but are not evolutionary related. These structures are due to _________.

similar selective pressures Signup and view all the answers

Organs or other structures that appear in different animals and are similar in structure and location but may be put to different uses are called _________.

homologous structures Signup and view all the answers

Which of the following provides supporting evidence of evolution? (Select all that apply)

All of the answer choices are correct Signup and view all the answers

Much of the evolutionary history of vertebrates can be seen in the way in which their _________ develop.

embryos Signup and view all the answers

_________ are preserved remains of dead organisms that have been buried and mineralized over time.

Fossils Signup and view all the answers

The wings of bats, pterosaurs, and birds are examples of _________ structures that resulted from convergent evolution.

analogous Signup and view all the answers

Darwin sailed on the HMS beagle as a naturalist collecting scientific data from 1831 to 1836. What hypothesis did Darwin form?

Biological organisms evolve over time by means of natural selection. Signup and view all the answers

Along with his geological observations, Darwin's studies of fossils suggested that the living forms of organisms were related to similar extinct forms. What did he observe?

Characteristics of similar species varied from place to place. Signup and view all the answers

What occurred in the red bacterial cell that generated genetic diversity and allowed natural selection to later act on this population?

Mutation occurred Signup and view all the answers

The fossil record consists mainly of bones, shells, or teeth because these remains are usually preserved when organisms become buried in sediment. What can fossils show us?

Successive change in organisms over time Signup and view all the answers

Place the following images in order to reflect the progress of whale evolution over time.

1, 4, 2, 3 Signup and view all the answers

Embryology is the study of the developmental stages of an embryo. What common features do all vertebrates possess?

Post-anal tail Signup and view all the answers

Structures that are anatomically similar because they were inherited from a common ancestor are called _________.

homologous structures Signup and view all the answers

Genetic drift refers to changes in the allele frequencies of a gene pool due to chance.

True Signup and view all the answers

In small populations, gene frequencies can change drastically by chance alone. This phenomenon is called _________.

genetic drift Signup and view all the answers

When only a very few individuals give rise to a new population in a new area of favorable habitat, the new population might possess different genotype frequencies. This is called the _________ effect.

founder Signup and view all the answers

In human infants, there has long been evolution toward having the highest survival rate at a 6-7 pound birth weight. This is an example of _________.

stabilizing selection Signup and view all the answers

When selection operates to eliminate intermediate phenotypes, it is referred to as _________.

disruptive selection Signup and view all the answers

The frequency of sickle-cell disease in Central African humans is an example of _________.

directional selection Signup and view all the answers

Two populations of flowers are separated by a mountain range and would not be capable of interbreeding. This is an example of _________ isolation.

geographical Signup and view all the answers

If two species of plants bloom during different seasons in the same habitat, this is known as _________ isolation.

temporal Signup and view all the answers

Until recently, selection favored the darker form of the peppered moth in areas affected by the industrial revolution.

False Signup and view all the answers

Which of the following statements are true regarding the alleles for the β-hemoglobin gene? The allele for normal hemoglobin is S and the defective allele (Sickle Cell allele) is s.

Persons who are homozygous for the defective allele (genotype ss) have a reduced life span. Signup and view all the answers

Selection that favors one extreme of the array of phenotypes is called _________.

directional selection Signup and view all the answers

_________ isolating mechanisms include improper development of hybrids and failure of hybrids to become established in nature.

postzygotic Signup and view all the answers

A _________ is a separate group of organisms incapable of interbreeding with other such groups.

species Signup and view all the answers

The Hardy-Weinberg equilibrium is based on a number of assumptions. Which of the following is not one of those?

Mating occurs in a nonrandom pattern. Signup and view all the answers

The bottleneck effect and the founder effect are two types of _________.

genetic drift Signup and view all the answers

Study Notes

Evolution and Natural Selection

Charles Darwin proposed the theory of evolution in 1859, supported by extensive evidence.
Key evidence includes fossil records, distinctive biogeography, and observable species variations.
Thomas Malthus’s work on population growth influenced Darwin’s understanding of natural selection.
Natural selection operates when organisms with advantageous traits survive and reproduce more effectively.

Fossils and Structural Evidence

Fossils represent preserved remains of organisms, showing evolutionary changes over time.
Whales evolved from hoofed mammals, evidencing transitions in fossil records.
Analogous structures arise from similar selective pressures but are not evolutionarily related, while homologous structures are similar due to common ancestry.

Molecular and Embryological Evidence

Molecular analysis provides insights into evolutionary relationships, revealing greater genetic differences in distantly related species.
Embryological studies highlight common developmental traits among vertebrates, indicating shared ancestry.
The Hardy-Weinberg equilibrium predicts allele frequencies in populations under specific conditions, such as large size and random mating.

Genetic Drift and Selection

Genetic drift results in chance-based changes in allele frequencies, particularly impactful in small populations.
The founder effect occurs when a small group establishes a new population, potentially leading to different genotype frequencies from the original larger population.
Three types of natural selection are recognized: stabilizing (favoring intermediate phenotypes), directional (favoring one extreme phenotype), and disruptive (favoring extreme phenotypes over intermediates).

Isolation Mechanisms and Speciation

Geographical isolation prevents interbreeding between populations, leading to speciation.
Ecological isolation occurs when populations occupy different habitats, while temporal isolation arises from differences in breeding seasons.
Mechanical isolation involves physical barriers preventing successful mating.

Selection Examples in Human Populations

Sickle-cell disease exemplifies directional selection; homozygous individuals do not survive as well as heterozygous individuals, who benefit from a survival advantage against malaria.
Human birth weight is subject to stabilizing selection, where intermediate weights enhance survival rates.

Principles of Evolutionary Change

The Hardy-Weinberg law outlines expectations for allele frequencies in a population, assuming no mutations or migrations.
Understanding genetic mechanisms helps scientists trace evolutionary change and population dynamics over time.### Evolutionary Phenomena
Light phenotype was more common before industrialization; pollution led to increased frequency of dark phenotypes, illustrating industrial melanism.
Anti-pollution laws have resulted in a reversal of melanism in moths.
Melanism in desert pocket mice shows selection for phenotypes matching environmental conditions.

Species Concepts

Biological species concept defines species by groups of interbreeding populations that are reproductively isolated.
Reproductive isolation mechanisms can be prezygotic (e.g., mechanical, geographic, behavioral) or postzygotic (e.g., hybrid inviability, hybrid sterility).

Genetic Concepts

Genetic drift is a random process affecting population genetics.
The Miller-Urey experiment aimed to simulate early Earth's oxygen-free atmosphere to understand organic molecule formation.

Origin of Life

DNA is suspected to be the first macromolecule formed when life arose.
Early Earth’s atmosphere was largely devoid of oxygen, contrasting with modern conditions.
Miller-Urey's experiment demonstrated that complex biomolecules could form under prebiotic conditions.

Bacterial Characteristics

Prokaryotes represent the simplest and most abundant life forms today.
Flagella enable some bacteria to swim effectively.
Binary fission is unique to prokaryotes as a method of asexual reproduction.

Virus Structure and Function

Viruses are composed of a core of DNA or RNA surrounded by a protein coat, not considered living organisms.
Viral infections can occur through direct attachment to host cell receptors via viral spikes or by endocytosis where the host cell engulfs the virus.

Bacterial Conjugation and Plasmids

Bacterial conjugation involves direct contact between cells, pilus shortening, and the transfer of plasmids, leading to genetic variation.
Plasmids are small, circular DNA molecules found outside the main bacterial chromosome.

Environmental Adaptability

Under harsh conditions, some bacteria can form endospores to protect their DNA until favorable conditions return.
The Influenza virus was responsible for approximately 100 million deaths between 1918 and 1919.

Characteristics and Importance of Prokaryotes

Prokaryotes contribute significantly to ecosystems by decomposing waste, fixing nitrogen, and forming the base of the food chain.
They play a crucial role in human health, including maintaining a healthy digestive tract.

Evolution of Viruses

Emerging viral diseases may originate from zoonotic transmission, such as viruses passing from pigs to humans.

Biochemical Processes

The process of forming complex organic molecules from simpler ones could be catalyzed by environmental factors like electricity and clay.

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Test your knowledge of key concepts in Biology 101 with these flashcards. This quiz covers Charles Darwin's theories on evolution and the evidence he presented. It's an essential resource for students wanting to reinforce their understanding of evolutionary biology.

Biology 101 Flashcards

Questions and Answers

What type of selection favors a midsized body?

What does directional selection do?

What type of selection eliminates intermediate phenotypes?

The intermediate phenotype is favored in _____ selection.

What is sickle-cell disease?

Which of the following is an advantage of being heterozygous for sickle-cell disease?

What does industrial melanism refer to?

According to the biological species concept, a species is comprised of groups that are reproductively isolated. True or False?

Match the following reproductive isolating mechanisms with their type:

Genetic drift is a random process.

What major component was reconstructed in the Miller-Urey experiment?

What was suspected to be the first macromolecule that formed when cells first arose?

Which gas would likely be excluded from Earth's early atmosphere?

The main problem with the Miller-Urey experiment was that it didn't include the role of the ozone layer.

What is the simplest and most abundant form of life on Earth today?

What do some bacteria use to swim?

Which process is exclusive to prokaryotes and not found in eukaryotes?

Viruses consist of a core segment of DNA or RNA surrounded by a _____ coat.

Viruses contain _____ as the form of genetic material.

All viruses have an envelope around their capsid.

Where did the COVID-19 virus most likely originate?

Viruses that can infect bacterial cells are called?

During bacterial conjugation, plasmid replication occurs in _____ the donor and recipient.

The pilus is found on both the donor and recipient cells.

Plasmids are small circles of DNA outside the main bacterial chromosome.

Label the essential components of an animal virus.

What do viral spikes do?

In viral entry by endocytosis, what happens?

After the virus is released from the vesicle into the host cell cytoplasm, what happens next?

Under harsh environmental conditions, some bacteria are able to form thick-walled _____ to protect their DNA.

What virus was responsible for killing approximately 100 million people between 1918 and 1919?

Complete the following statements about the characteristics of viruses: 1) _____ nucleic acid; 2) _____ protein; 3) _____ chemical; 4) _____ cellular; 5) _____ reproduce.

Earth's early atmosphere contained hydrogen-rich gases like hydrogen sulfide, _____, and methane.

Scientists propose that early Earth’s energy sources could have driven chemical reactions that formed _____ molecules.

What is the term used to describe the gases released from volcanoes under the sea?

What type of organisms do Archaea and Bacteria both consist of?

Prokaryotic cells lack a _____ and have a plasma membrane surrounded by a _____ wall.

Select all of the ways prokaryotes are important for humans and ecosystems.

The filament of the bacterial flagellum extends out of the cell.

The movement of the filament of the flagellum is a rotation that causes bacteria to _____ as it moves.

Prokaryotic organisms can reproduce asexually by _____, in which the DNA replicates.

What is the process called when bacteria exchange genetic information through a pilus?

When faced with unfavorable conditions, some bacteria form thick-walled _____ to protect their DNA.

Give an example of an origin of an emerging viral disease.

In 1859, naturalist _________ suggested an explanation for why evolution occurs.

Darwin's evidence that evolution occurs includes which of the following? (Select all that apply)

Darwin better understood the mechanism for natural selection after he read a book by _________ on the rate of growth of populations.

Sizes of natural populations remain relatively stable over time because _________ limits population numbers.

Darwin's main principle of natural selection was that every organism has the potential to produce more offspring than can survive, and those individuals that are better suited to their environment are more likely to survive.

The final stimulus that convinced Darwin to publish his findings came from a young English naturalist, _________, who had come to the same conclusion as Darwin.

Darwin's finches proved that beak sizes were the result of _________.

The notion that more distantly related organisms should have accumulated a greater number of evolutionary differences is best illustrated using _________.

The fossil record indicates that whales evolved from _________.

Analogous structures are those similar in organisms but are not evolutionary related. These structures are due to _________.

Organs or other structures that appear in different animals and are similar in structure and location but may be put to different uses are called _________.

Which of the following provides supporting evidence of evolution? (Select all that apply)

Much of the evolutionary history of vertebrates can be seen in the way in which their _________ develop.

_________ are preserved remains of dead organisms that have been buried and mineralized over time.

The wings of bats, pterosaurs, and birds are examples of _________ structures that resulted from convergent evolution.

Darwin sailed on the HMS beagle as a naturalist collecting scientific data from 1831 to 1836. What hypothesis did Darwin form?

Along with his geological observations, Darwin's studies of fossils suggested that the living forms of organisms were related to similar extinct forms. What did he observe?

What occurred in the red bacterial cell that generated genetic diversity and allowed natural selection to later act on this population?

The fossil record consists mainly of bones, shells, or teeth because these remains are usually preserved when organisms become buried in sediment. What can fossils show us?

Place the following images in order to reflect the progress of whale evolution over time.

Embryology is the study of the developmental stages of an embryo. What common features do all vertebrates possess?

Structures that are anatomically similar because they were inherited from a common ancestor are called _________.

Genetic drift refers to changes in the allele frequencies of a gene pool due to chance.

In small populations, gene frequencies can change drastically by chance alone. This phenomenon is called _________.

When only a very few individuals give rise to a new population in a new area of favorable habitat, the new population might possess different genotype frequencies. This is called the _________ effect.

In human infants, there has long been evolution toward having the highest survival rate at a 6-7 pound birth weight. This is an example of _________.

When selection operates to eliminate intermediate phenotypes, it is referred to as _________.

The frequency of sickle-cell disease in Central African humans is an example of _________.

Two populations of flowers are separated by a mountain range and would not be capable of interbreeding. This is an example of _________ isolation.

If two species of plants bloom during different seasons in the same habitat, this is known as _________ isolation.

Until recently, selection favored the darker form of the peppered moth in areas affected by the industrial revolution.

Which of the following statements are true regarding the alleles for the β-hemoglobin gene? The allele for normal hemoglobin is S and the defective allele (Sickle Cell allele) is s.

Selection that favors one extreme of the array of phenotypes is called _________.

_________ isolating mechanisms include improper development of hybrids and failure of hybrids to become established in nature.

Complete the following statements about the characteristics of viruses: 1) ___ nucleic acid; 2) _ protein; 3) _ chemical; 4) _ cellular; 5) ___ reproduce.

Prokaryotic cells lack a _ and have a plasma membrane surrounded by a _ wall.