Class Lecture- Evolution II: Speciation and Extinction

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38 Questions

What is the term for the retention of juvenile characteristics in an organism?

Neoteny

What is the classic example of sequence heterochrony mentioned in the text?

Axolotl

What is the cause of the Cretaceous mass extinction event?

Meteor impact

What is the term for changes in the appearance of different phenotypes at life stages when they normally would not occur?

Sequence heterochrony

What is the current threat to amphibians mentioned in the text?

All of the above

What is the term for the accelerated rate of extinction caused by human-induced causes?

Anthropogenic extinction

What is the term for the retention of juvenile characteristics in humans, such as retaining baby faces?

Neoteny

What is the term for the phenomenon where the extinction rate tends to track with human population growth rate?

Correlation

What is the term for the biomass decrease of insects by 76% in 30 years in Germany?

a form of Mass extinction

What is the term for the event that involves a global extinction event killing roughly greater than 50% of species on the planet?

Mass extinction event

What is the gradualistic model in evolutionary biology based on?

Regular, slow phenotypic change occurring at a roughly constant rate

What is the punctuated equilibrium model in evolutionary biology characterized by?

Long periods of stasis with intermittent rapid speciation

What is an example of the punctuated equilibrium model?

The formation of 400 new species of cichlid fish in African Lake Victoria in 12,000 years

What is sympatric speciation?

Speciation occurring with overlapping ranges of different subpopulations

Why is the gradualistic model and the punctuated equilibrium model considered wrong?

They are not always applicable and depend on the context

What is the tempo of evolution in the punctuated equilibrium model characterized by?

Occurring in fits and starts with long periods of stasis

What is an example of the tempo of evolution in the gradualistic model?

The gradual formation of the Grand Canyon over time

What is the tempo of speciation in the punctuated equilibrium model characterized by?

Occurring in fits and starts with intermittent rapid speciation

What is the tempo of phenotypic change in the gradualistic model based on?

Regular, slow phenotypic change occurring at a roughly constant rate

What is an example of a species that has been around for a very long time?

Horseshoe crabs, which have been around for 100 million years

What is anagenesis?

The gradual evolution from one species to the next

What is an example of sympatric speciation?

Polyploidy in plants

What can be altered by a single point mutation, resulting in a complete reconfiguration of the body plan?

HOX genes

What is heterochrony?

Changes in the timing or sequence of development

What is the primary reason for the high value of horseshoe crab blood?

Its immune properties

What is cladogenesis?

Branching off into two or more species

What can natural selection work on?

Existing structures

What is an example of allometric heterochrony?

Domesticated dogs' changes in size compared to their wolf ancestors

Is the gradualistic model based on the idea of regular, slow phenotypic change occurring at a roughly constant rate that leads to new species?

True

Is the punctuated equilibrium model characterized by long periods of stasis with no change, followed by big adaptive radiation, and then no change again?

True

Is the example of cichlid fishes occurring in African Lake Victoria potentially an example of sympatric speciation?

True

Sympatric speciation in plants commonly occurs through polyploidy, where a genome duplication event leads to the formation of a new species.

True

HOX genes can be altered by a single point mutation, resulting in a complete reconfiguration of the body plan.

True

Examples of heterochrony include allometric heterochrony, which is difficult to measure due to occurring early in development and a long time ago.

False

Neoteny refers to the retention of adult characteristics in an organism?

False

The accelerated rate of extinction is a natural part of life and has been well-documented in the fossil record?

False

The axolotl is an example of sequence heterochrony because it retains its external gills into adulthood?

True

The biomass of insects in Germany has increased by 76% in 30 years?

False

Study Notes

Horseshoe Crabs, Evolution, and Speciation

  • Horseshoe crabs have undergone minimal change despite facing various environmental challenges and predators.
  • Horseshoe crab blood is highly valuable due to its immune properties, fetching a price of 60-80k per gallon and is used in vaccine development.
  • The visual representation compares gradualism, where small regular changes lead to new species, to the punctuated equilibrium model, where rapid bursts of change occur.
  • Anagenesis refers to gradual evolution from one species to the next, while cladogenesis involves branching off into two or more species.
  • The rate of speciation is influenced by factors such as mutation rate, strength of natural selection, generation time, and environmental change.
  • Natural selection can work on existing structures, as seen in the evolution of the eel's jaws and the fish's lure.
  • Sympatric speciation in plants is common, often through polyploidy, where a genome duplication event leads to the formation of a new species.
  • HOX genes can be altered by a single point mutation, resulting in a complete reconfiguration of the body plan.
  • Heterochrony, involving changes in the timing or sequence of development, can impact rates of speciation and lead to different phenotypes.
  • Examples of heterochrony include allometric heterochrony, which is difficult to measure due to occurring early in development and a long time ago.
  • Domesticated dogs exemplify allometric heterochrony, showing changes in size through time compared to their wolf ancestors.
  • Heterochrony can lead to phenotypic changes that contribute to differential reproductive success, shaping evolutionary patterns.

Horseshoe Crabs, Evolution, and Speciation

  • Horseshoe crabs have undergone minimal change despite facing various environmental challenges and predators.
  • Horseshoe crab blood is highly valuable due to its immune properties, fetching a price of 60-80k per gallon and is used in vaccine development.
  • The visual representation compares gradualism, where small regular changes lead to new species, to the punctuated equilibrium model, where rapid bursts of change occur.
  • Anagenesis refers to gradual evolution from one species to the next, while cladogenesis involves branching off into two or more species.
  • The rate of speciation is influenced by factors such as mutation rate, strength of natural selection, generation time, and environmental change.
  • Natural selection can work on existing structures, as seen in the evolution of the eel's jaws and the fish's lure.
  • Sympatric speciation in plants is common, often through polyploidy, where a genome duplication event leads to the formation of a new species.
  • HOX genes can be altered by a single point mutation, resulting in a complete reconfiguration of the body plan.
  • Heterochrony, involving changes in the timing or sequence of development, can impact rates of speciation and lead to different phenotypes.
  • Examples of heterochrony include allometric heterochrony, which is difficult to measure due to occurring early in development and a long time ago.
  • Domesticated dogs exemplify allometric heterochrony, showing changes in size through time compared to their wolf ancestors.
  • Heterochrony can lead to phenotypic changes that contribute to differential reproductive success, shaping evolutionary patterns.

Explore the fascinating world of horseshoe crabs, evolution, and speciation in this quiz. Delve into the concepts of gradualism and punctuated equilibrium, the impact of natural selection, and the role of genetic changes such as heterochrony and HOX genes. Discover how environmental factors and genetic mutations influence the rate of speciation and gain insights into examples of speciation in plants and animals.

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