D: Biology = Changes in Living Systems 2.4 Adaptations and 2.5 Evolutionary Theory Flashcards
What year did Charles Darwin set sail on the HMS Beagle?
1831
What was Charles Darwin’s role on the HMS Beagle?
Naturalist
What did Darwin collect during his voyage on the HMS Beagle?
A huge number of species of plants and animals
What is the name of the volcanic islands that fascinated Darwin?
Galapagos Islands
What type of regions do the Galapagos Islands have?
Different climatic regions
What did Darwin observe about the organisms on the Galapagos Islands?
Strong similarities between organisms with different adaptations
What did Darwin hypothesize about the variety of finches he found?
They must be related
What are the three types of beaks observed in Galapagos finches?
- Thick beaks for crushing hard seeds
- Parrotlike beaks for eating fruit
- Slim beaks for catching insects
Fill in the blank: Darwin suggested that the finches all came from a common _______ ancestor.
seed-eating
How did Darwin believe finches arrived at the Galapagos Islands?
They were blown to the islands from the mainland
What happened to the finch populations after arriving on the Galapagos Islands?
Their populations soared due to abundant food and lack of predators
What caused the finch population to face a lack of food?
The habitat lacked enough seeds to support the large population
What kind of variation exists within finch populations according to Darwin?
Variation in many traits including beak characteristics
What happens to finches best suited to consume available food sources on the island?
They survive to breed with other successful birds with similar beaks
What is passed on to the offspring of finches with advantageous beak types?
Genes for their beak type
What resulted from generations of finches adapting to specific food sources?
Lines of birds that were each adapted to collecting a specific food source
What differences can be observed in the distinct lines of finches?
Beak shape, food eaten, mating behaviour, and other differences
What environmental pressure influenced the adaptation of finches?
Limited food
Fill in the blank: Over many generations, several new finch species ______ that were well-adapted to eating different foods than their ancestors did.
developed
True or False: The finches’ adaptations were a result of random genetic mutations.
False
What year did Charles Darwin publish his book, On the Origin of Species?
1859
What does the term ‘evolution’ literally mean?
Unrolling or opening out
In a biological context, what does evolution refer to?
A change in the characteristics of a population over time
What did Darwin propose about all life on Earth?
All life shares a common ancestor
What was the initial public response to the first printing of Darwin’s book?
It sold out on its first day of publication
What common belief did Darwin’s writing challenge?
That organisms were fixed in their present form and unchanged since Earth’s creation
What is an observable fact regarding organisms over geological time?
Organisms have changed
What remains controversial about the changes in organisms over time?
The explanation of how these changes occurred
What are the three observations that form the basis of Darwin’s theory of natural selection?
- Organisms usually produce more offspring than can survive
- There is variation among individuals with respect to any trait in a population
- Organisms within a population compete for limited resources
What does Darwin’s theory of natural selection state?
Only those individuals best adapted to compete for limited resources are most likely to survive
What term is used to describe individuals in a population that are best adapted to their environment?
Darwinian fitness
What does Darwinian fitness measure?
The reproductive success of an organism
Fill in the blank: The theory of evolution states that the nature of a population gradually changes form over _______.
Time
True or False: Darwinian fitness is a measure of an organism’s speed, strength, or health.
False
What does the theory of natural selection propose?
Evolution occurs because more organisms are produced than can survive
What happens to advantageous traits according to natural selection?
They are passed on to offspring by the organisms that survive and reproduce
What is the process by which advantageous traits become more common in a population over generations?
Natural selection
This process leads to the evolution of species through the survival of the fittest.
What two essential requirements must be met for natural selection to occur?
- There must be a genetic basis for the variation observed in some trait.
- There must be differences in the rate of survival and reproduction associated with the possession of a certain trait.
How does Darwin’s theory define success in natural selection?
Success is defined in terms of organisms that live to reproduce and pass along their traits to offspring.
What are the two models that describe the pace of evolutionary changes in a population?
- Gradualism
- Punctuated equilibrium
What role does the environment play in natural selection?
The environment establishes the criteria for determining which organisms will be successful.
True or False: The theory of natural selection can only explain gradual changes in a population.
False
The theory can explain both gradual changes and sudden changes in populations.
Fill in the blank: The ability of Darwin’s theory to explain both gradualism and _______ is why it continues to be used.
[punctuated equilibrium]
What catastrophic event is suggested to have triggered a sudden change in Earth’s climate about 65 million years ago?
Meteorite impact
Geological evidence points to this event affecting the survival of large dinosaurs.
Which type of organisms were more successful in the cooler environments following the climate change?
Small, warm-blooded mammals
What allowed the more successful mammals to thrive in the changed environments?
Physical traits that enabled survival in the new environment.
Who developed the theory of natural selection?
Charles Darwin
Darwin is often credited for the theory due to his extensive research and publication.
What significant event occurred in 1858 regarding Darwin’s work?
Darwin and Wallace presented their work together to the scientific community
This was a pivotal moment in the acceptance of natural selection.
What was the title of Darwin’s famous book published in 1859?
Origin of Species
This book outlined Darwin’s theory of evolution through natural selection.
Who was Alfred Russel Wallace?
A colleague of Darwin who independently developed the theory of natural selection
Wallace’s paper prompted Darwin to publish his findings.
Fill in the blank: Darwin didn’t publish his theory until a colleague, ________, sent him a paper.
Alfred Russel Wallace
True or False: Darwin published his theory before Wallace.
False
Darwin published his theory after Wallace’s paper.
What did Darwin focus on for two decades after his voyage?
Developing his theory and collecting further evidence
This research was crucial for the formulation of his theory.
What was the title of the paper sent to Darwin by Wallace?
The Struggle for Existence
Who proposed a different reason for why populations changed before Darwin and Wallace?
Jean-Baptiste Lamarck
Lamarck’s ideas were foundational in the discussion of evolution, even though they were later disproved.
What hypothesis did Lamarck propose regarding how organisms changed?
Organisms changed during their lives to meet environmental challenges, and these changes were passed on to offspring
This is known as the inheritance of acquired characteristics.
What did Lamarck believe about unused parts of organisms?
Parts not used would eventually disappear
This concept was part of his theory on how organisms adapt to their environments.
How did Lamarck explain the long necks of giraffes?
Giraffes stretched their necks to reach higher leaves, leading to longer necks in subsequent generations
This explanation is an example of his theory of acquired characteristics.
What was the fate of Lamarck’s idea of the inheritance of acquired characteristics?
It was dismissed due to lack of evidence
Lamarck’s theories were ultimately proven incorrect.
What recent understanding contradicts Lamarck’s hypothesis about traits?
Changes in traits require changes in the genes responsible for those traits
This understanding is fundamental in modern genetics.
Fill in the blank: The long necks of giraffes are due to _______ rather than stretching.
genetics
This highlights that physical changes from behavior do not affect genetic inheritance.
True or False: Lamarck’s ideas were proven correct by subsequent scientific research.
False
Lamarck’s theories were disproven by later advances in genetics.
What did Lamarck’s work contribute to the field of biology?
He prompted people to think about how species change over time
Despite being incorrect, his ideas were significant in the evolution of evolutionary thought.
What are homologous structures?
Structures that are variations in size and shape of the same number of bones across different species.
Examples include a human arm, a whale flipper, and a bat wing.
What does the geological record indicate about Earth?
Earth has undergone dramatic changes over time, and organisms did not remain static.
What does the theory of evolution explain?
How changes to organisms have taken place over time.
What supports the theory of evolution?
Multiple pieces of evidence that together make a strong case for its validity.
Each piece alone is not proof of the theory.
Fill in the blank: The __________ record indicates that organisms did not remain static.
fossil
What is suggested by similarities in embryonic development among different species?
A common ancestor.
True or False: The theory of evolution is supported by individual pieces of evidence that each prove it.
False
List examples of species that display homologous structures.
- Human arm
- Whale flipper
- Bat wing
What does embryonic similarity among species suggest?
It suggests a shared ancestral origin.
Fill in the blank: The theory of evolution provides an explanation for how __________ changes would have taken place.
organism
What are vestigial structures?
Tiny, useless wings on an insect and dew claws on a dog that have no apparent function.
The presence of these structures suggests that the organism’s ancestors had a more useful version of the body part.
What does the presence of vestigial structures indicate?
That the organism’s ancestors had a more useful version of the body part and that the role for these structures has been lost through adaptation over time.
What is the significance of the same set of 20 amino acids in all organisms?
It suggests that all forms of life are related to some extent, having common ancestors in the earliest organisms.
This is known as biochemical evidence.
How can behavior evolve by natural selection?
If inherited behaviors affect an organism’s fitness to the environment, then those behaviors can evolve.
An example is the calling songs of crickets.
What does biogeography study?
The geographical distribution of organisms and how organisms separated by barriers show related characteristics.
This suggests a common ancestor migrated long ago.
Fill in the blank: The proteins in all organisms are produced from the same set of _______.
[20 amino acids]
True or False: Biogeographical evidence suggests that two populations changed in the same way to become distinct species.
False
It suggests that two populations changed in different ways.
What is an example of an evolved behavior?
The calling songs of crickets.
What role do inherited behaviors play in evolution?
They can affect an organism’s fitness and thus can evolve through natural selection.
What is the peppered moth an example of?
Natural selection
The peppered moth illustrates how environmental changes can influence the survival of species.
Why is the moth called ‘peppered’?
Because it looks like someone has sprinkled pepper on its white wings.
When is the peppered moth active?
During the night (nocturnal).
What is the primary habitat of the peppered moth during the day?
Resting on the bark of trees.
What effect did the Industrial Revolution have on the peppered moth population in Manchester?
It changed the camouflage of the moth due to soot covering surfaces.
What caused the soot that affected the peppered moth’s camouflage?
The combustion of coal in factories.
How did the change in the environment affect the survival of the light-colored peppered moths?
They stood out against the black background, making them easier prey for birds.
What happened to the population of light-colored peppered moths over about 100 years in polluted areas?
A majority of the population became black.
In what type of environment was the black form of the peppered moth still rare?
In unpolluted forests.
True or False: Black peppered moths were common in polluted areas during the Industrial Revolution.
True.
Fill in the blank: The peppered moth’s color provides _______ against predators.
Camouflage.
What does each cell in your body carry?
All the information to make an exact copy of you.
Could any cell in your body be used to develop a replica or clone of you?
Yes, advances in technology may have made this possible.
What significant cloning achievement occurred in 1996?
Scientists in Scotland successfully cloned a sheep named Dolly.
What was unique about Dolly the sheep?
She was an exact copy of the adult sheep whose cell she was cloned from.
How do many plants reproduce naturally?
By cloning or by asexual reproduction.
What happens when detached cells grow?
They grow into new identical plants.
What do gardeners do to take advantage of plants’ ability to clone?
They take cuttings from plants.
Define asexual reproduction.
The production of identical offspring from a single parent cell.
List the methods of asexual reproduction.
- Budding
- Division of a single cell
- Division of the entire organism into two or more parts.
What type of reproduction requires only one parent?
Asexual reproduction
Why do most organisms reproduce sexually?
To increase genetic variation
What is a potential issue with a population of identical organisms when environmental conditions change?
They may not be able to cope with the new environment
What does sexual reproduction provide to offspring?
A different combination of the parents’ genes
What is the overall effect of sexual reproduction on a population?
Increase the degree of variation within the population
How does the environment influence which traits are passed on in a population?
It selects the varieties with traits that make them fittest for survival
What is the result of breeding successful organisms in a population?
Change in the population’s appearance
As a population adjusts to its environment, what happens to the number of organisms possessing certain traits?
It increases
What process is observed as a population adapts to remain successful in its environment?
Evolution
Fill in the blank: Asexual reproduction is _______ and efficient.
quick
True or False: Sexual reproduction results in identical offspring.
False
What was the name of the cloned sheep introduced in 1996?
Dolly
What chapter discusses variation within a population as a result of sexual reproduction?
This chapter
What is evolution?
Evolution is the slow and gradual change in the characteristics of population over time.
This concept is fundamental to understanding biological changes across generations.
Who proposed that natural selection is the mechanism that drives evolution?
Charles Darwin
Darwin’s theory of natural selection emphasizes survival of the fittest.
What idea did Lamarck propose regarding evolution?
The inheritance of acquired characteristics.
This idea was later proven to be incorrect.
What are examples of evidence that support Darwin’s theory of evolution?
- Selective breeding
- Vestigial structures
- Look-alike embryos
- Geology and paleontology of Earth
These pieces of evidence demonstrate the mechanisms and results of evolutionary processes.
How does sexual reproduction affect variation in a population?
Sexual reproduction creates variation and improves the chances of success in a population.
This increased genetic diversity can enhance adaptability to changing environments.
True or False: Lamarck’s theory of the inheritance of acquired characteristics is widely accepted today.
False
Lamarck’s theory has been largely discredited in favor of Darwin’s natural selection.
Fill in the blank: _______ is the mechanism that drives evolution according to Darwin.
[natural selection]
Natural selection is a key concept in evolutionary biology.
