44 Questions
Which of the following statements about allopatric and sympatric speciation is correct?
Sympatric speciation can occur among individuals living in the same area without geographic separation.
What type of reproductive isolation is exemplified by the inability of male damselflies of one species to mate with females of another species due to anatomical differences in the male copulatory organ?
Mechanical; prezygotic
When reconstructing evolutionary history using the parsimony principle, what do scientists look for in selecting trees?
A tree with the fewest shared, derived characters.
What is the primary model used by evolutionary biologists until about 50 years ago?
Gradualism
What is the process that leads to the formation of new species?
Macroevolution
Who extensively described punctuated equilibrium?
Stephen J. Gould
What is the role of natural selection in evolution?
Acts on individuals
What controls the speed with which evolution progresses and species are formed?
Rate of evolution and extinction
What is the concept that suggests sudden episodes of speciation after prolonged periods of stasis?
Punctuated equilibrium
What is the term for a change in the frequencies of genotypes in a population?
Microevolution
What does heterochrony include?
Change in the rate of growth or development
What is an example of heterochrony?
Domesticated dogs reaching maximum size earlier than wolves
What is the estimated current extinction rate compared to the rates discernible from the fossil record?
About 100 times higher
What are the causes believed to have led to the Cretaceous mass extinction?
Volcanoes or a meteor impact
What follows mass extinction events, favoring the propagation of new species?
Periods of punctuated speciation
What do most phylogenetic trees depict about organisms?
Hierarchical relationship
What does the term 'anthropocene' signify?
The period during which human activity is the dominant influence on climate and the environment
Which concept is exemplified by the rapid evolution of 400 species of cichlid fish in Lake Victoria in just 12,000 years?
Punctuated equilibrium
What is the process in which a parent species splits into distinct species as populations adapt to new environments?
Cladogenesis
Which factor controls the rate of speciation in evolutionary processes?
Mutation rates
What is the term for when a structure evolves for one purpose and is later used for another purpose?
Exaptation
Which genetic process can lead to rapid speciation in both plants and animals?
Polyploidy
What are the two concepts linked to gradualism and punctuated equilibrium in evolutionary processes?
Anagenesis and cladogenesis
Which type of evolution involves slow, progressive changes at a constant rate, reflecting a slow divergence of isolated populations over time?
Gradualism
What does natural selection act on?
Individuals
On what does evolution act?
Populations
What is the primary focus of natural selection?
Survival and reproduction of individuals
What is neoteny?
Retention of juvenile traits in adults
What does sequence heterochrony refer to?
Change in the time at which a structure appears
How has delayed development benefited the Axolotl?
Allowed it to live in aquatic environments
What percentage of all terrestrial species were wiped out during the Cretaceous mass extinction?
71%
What percentage of all genera were wiped out during the Permian mass extinction?
83%
Which animal is thought to be the common ancestor of all modern mammals?
Lystrosaurus
What is the primary difference between the evolution of cichlid fish in Lake Victoria and horseshoe crabs?
Cichlid fish underwent rapid evolution while horseshoe crabs underwent gradual evolution
What is the significance of horseshoe crabs in relation to human drugs and vaccines?
Their blood, used to identify toxins, is critical for sterilizing human drugs and vaccines
What evolutionary concepts do the examples of cichlid fish and horseshoe crabs illustrate?
Cichlid fish exemplify punctuated equilibrium while horseshoe crabs exemplify gradualism
What is exaptation in the context of evolution?
The evolution of a structure for one purpose and its later use for another purpose
What is the significance of hollow bones in the evolution of wings in birds?
Hollow bones existed before birds could fly and are an example of exaption.
How did flight evolve in birds according to the text?
Birds escaped from predators by climbing up trees, and their appendages became modified for flight
Which genetic process can lead to rapid speciation in both plants and animals?
Gene duplication
What is an example of allometric heterochrony?
Early maturation in domesticated dogs compared to wolves
What type of gene is important for the early organization and development of the body?
Homeotic (Hox) genes
What is the result of polyploidy in organisms?
Prevents mating with individuals having only one copy of the genome
What can lead to significant phenotypic changes in organisms?
Changes in developmental timing or the sequence of events (heterochrony)
Study Notes
Evolution and Speciation
- Stephen Jay Gould was known for popular science literature that explained science in an accessible way for the general public.
- Earth's evolution exhibits both gradualism and punctuated equilibrium, as shown in fossil records.
- Cichlid fish in Lake Victoria underwent rapid evolution, with 400 species evolving in just 12,000 years, a prime example of punctuated equilibrium.
- Horseshoe crabs underwent phenotypic stasis and gradual evolution for 100 million years, showcasing gradualism.
- Gradualism and punctuated equilibrium are linked to anagenesis and cladogenesis in evolutionary concepts.
- Gradualism involves slow, progressive changes at a constant rate, reflecting a slow divergence of isolated populations over time.
- Cladogenesis occurs when a parent species splits into distinct species as populations adapt to new environments.
- The rate of speciation is controlled by factors like mutation rates, selection rates, and environmental change rates.
- Speciation does not occur from nothing; it starts with existing structures, and exaptation occurs when a structure evolves for one purpose and is used for another.
- Flight evolution in birds and the development of wings in dinosaurs are examples of morphological changes to an existing structure.
- Rapid speciation can be caused by genetic and developmental processes that change an organism's phenotype while maintaining function.
- Polyploidy and alterations in developmental genes, such as Hox genes, can lead to rapid speciation in plants and animals.
Test your knowledge of evolution and speciation with this quiz! Explore concepts like gradualism, punctuated equilibrium, anagenesis, cladogenesis, and the factors influencing speciation rates. From famous examples like the cichlid fish in Lake Victoria to the role of genetic and developmental processes in rapid speciation, this quiz covers a wide range of evolutionary topics.
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