Patterns in Evolution and Extinction

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Questions and Answers

What is the primary cause of genetic variation within a population?

Natural selection

Environmental factors

Phenotypic changes

Germ-line mutations (correct)

Which of the following factors can act as selective forces in natural selection?

Reproductive isolation

Population size

Climatic factors (correct)

Genetic mutations

Natural selection has a specific goal to produce perfectly adapted organisms.

False

Individuals with favourable phenotypic characteristics are less likely to reproduce successfully.

False Signup and view all the answers

Name one mechanism that causes genetic variation apart from germ-line mutations.

Duplication of genes or swapping positions within chromosomes Signup and view all the answers

Sexual reproduction results in formations of new combinations of __________.

alleles Signup and view all the answers

What is the impact of industrialization on the peppered moth population?

Industrialization resulted in darker trees, favoring darker moth variants due to better camouflage from predators. Signup and view all the answers

Natural selection acts on _______ variation in a population.

genetic Signup and view all the answers

Match the following concepts with their descriptions:

Germ-line mutations = Main source of genetic variation Sexual reproduction = Creates new combinations of alleles Environmental factors = Influences phenotypic expression Natural selection = Mechanism for survival of the best adapted Signup and view all the answers

Match the following species to their selective pressures:

Peppered Moth = Predation Darwin's Finches = Resource competition Antibiotic-resistant Bacteria = Antibiotic exposure Sickle Cell Anemia = Malaria prevalence Signup and view all the answers

Which of the following is a factor that can lead to differential survival and reproduction?

Environmental conditions Signup and view all the answers

What is an effect of environmental changes on phenotypic characteristics?

It can make certain traits advantageous. Signup and view all the answers

Offspring phenotypes are always identical to their parents due to genetic inheritance.

False Signup and view all the answers

Name one mechanism of natural selection.

Differential survival and reproduction Signup and view all the answers

What outcome results from a variety of genotypes formed in the offspring?

A variety of phenotypes can be formed. Signup and view all the answers

Only genetic mutations contribute to genetic variation.

False Signup and view all the answers

What was a significant consequence of the extinction of dinosaurs?

An explosion of mammalian evolution Signup and view all the answers

Mass extinction events can occur simultaneously across many lineages.

True Signup and view all the answers

What is one trend seen in macroevolution according to the provided content?

Increasing complexity Signup and view all the answers

Evolving from marine habitats to _______ habitats is one pattern seen in the tree of life.

terrestrial Signup and view all the answers

Match the following trends with their descriptions:

Increasing complexity = Evolution from single cellular prokaryotes to highly complex eukaryotes Increasing body size = Coupled with increased cranial capacity Change in habitats = Evolving from aquatic to land ecosystems Phenotypic variation = Differences in physical traits among individuals Signup and view all the answers

What factor is primarily responsible for leaving ecological niches empty for mammals after the dinosaurs' extinction?

Climatic change Signup and view all the answers

Study Notes

Selective Forces and Natural Selection

Environmental pressures such as competition, predation, climatic factors, disease, and parasitism shape phenotypic adaptation.
Differential reproduction occurs when individuals with advantageous traits have a higher reproductive success.
Favourable phenotypic traits lead to increased fitness and successful reproduction, while unfavourable traits decrease reproductive success.

Example: Peppered Moth (Biston betularia)

Before the industrial revolution, light-colored moths blended with tree bark, making them less visible to predators.
Dark-colored variants were easily spotted by predators, leading to lower survival rates.
Post-industrial revolution, pollution darkened tree bark, favoured darker moths, which became less predatory targets.
With modern air pollution controls, lighter moths are favoured again as tree lichen returns, causing dark variants to become rarer.

Mechanisms of Evolution

No species is perfectly adapted; natural selection is a mechanical process without specific goals.
Genetic variation within populations is crucial for natural selection to operate effectively.

Sources of Genetic Variation

Germ-line mutations are the primary source of genetic variation.
Other sources include gene duplication, chromosomal swaps, and duplications or deletions of whole chromosomes.
Sexual reproduction results in new combinations of alleles, contributing to diverse offspring genotypes.

Phenotypic Differences in Offspring

Offspring phenotypes differ from parents due to genetic variation and environmental influences.
This process leads to a wide array of phenotypes, enhancing adaptability to changing conditions.

Evolutionary Diversification

Rapid diversification followed the extinction of dinosaurs, filling ecological niches left available by climatic changes.
Mammalian evolution increased significantly during this period, showcasing how environmental shifts prompt evolutionary changes.

Extinction Patterns

Extinction occurs frequently within lineages, affecting either individual lineages or causing mass extinctions across multiple lineages.
Each lineage has an inherent risk of extinction, shaping the evolutionary tree of life.

Trends in Macroevolution

Evolution showcases increasing complexity from simple prokaryotic life to advanced eukaryotic organisms.
Development of more complex societies, larger body sizes, and enhanced cranial capacities characterize evolutionary trends.
Transition from marine habitats to terrestrial and aerial environments marks significant ecological adaptations.

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Description

This quiz explores the rapid diversification of species after the extinction of dinosaurs and the impact of environmental changes on mammalian evolution. It examines the frequency and significance of both rare and mass extinctions across different lineages. Test your understanding of these key concepts in evolutionary biology!