Evolution and Natural Selection

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Questions and Answers

What is the primary focus of microevolution?

Phenotypic changes in individual organisms

Formation of new species from existing ones

Changes in species over millions of years

Alterations in allele frequencies in a population over time (correct)

Which statement is true regarding evolution at the population level?

Only individuals evolve, not populations.

Evolution occurs solely due to environmental factors.

Populations evolve through genetic changes over generations. (correct)

Populations exhibit observable change in a single generation.

What does macroevolution describe?

Immediate responses to environmental pressures in a population.

The evolution of genetic traits in individuals.

Descent with modification and the emergence of new species. (correct)

Small changes within species over time.

How does human activity relate to evolutionary change?

Humans can drive both microevolution and macroevolution. Signup and view all the answers

What is NOT true about evolution?

Individuals can evolve over their lifespan. Signup and view all the answers

Which concept illustrates that individuals do not evolve?

Evolution is measured in allele frequency changes in populations. Signup and view all the answers

What best describes the mechanism of change in allele frequencies?

Allele frequency changes occur due to mutation, selection, and genetic drift. Signup and view all the answers

In the context of evolution, what is meant by 'descent with modification'?

The way by which species diverge and evolve new traits over generations. Signup and view all the answers

What must be true for a trait to be subject to natural selection?

The trait must be heritable and genetically based. Signup and view all the answers

How does 'fitness' relate to natural selection?

Fitness measures the ability to reproduce relative to other individuals. Signup and view all the answers

Which of the following describes adaptation?

Traits that improve survival and reproduction in a specific environment. Signup and view all the answers

What characterizes genetic drift?

It is a random change in allele frequencies in a population. Signup and view all the answers

What is a key limitation of natural selection?

It can only work with existing variation. Signup and view all the answers

Why are mutations not the direct cause of evolutionary changes?

Mutations are random and not necessarily beneficial. Signup and view all the answers

What does heritability refer to in the context of traits?

The proportion of variation due to genetic differences. Signup and view all the answers

Why is seasonal fur color change in arctic animals not evolutionary change?

The change is reversible and not passed on genetically. Signup and view all the answers

Study Notes

Evolution

Changes in allele frequencies in a population over time are known as microevolution
Descent with modification, how species change over time and new species arise is known as macroevolution.
Individuals do not evolve, populations do.
Observable changes do not take millions of years.
Humans can cause evolutionary change.

Mechanisms of Evolution

Mutations can cause genetic variation
Gene flow can introduce new genetic variation
Genetic drift can cause changes in allele frequencies
Natural and sexual selection can select for advantageous traits.

Evolution by Natural Selection

Species change over time and become adapted to their environment.
Natural selection acts on heritable (genetic) variation.
Heritability of a trait is the proportion of variation in the trait due to genetic variation.
Seasonal changes in fur color in arctic animals is not evolutionary change, as the genetic makeup of the animals does not change.
Natural selection results in adaptations which are traits that improve survival and reproduction.
Fitness depends on the environment.
Fitness is the ability to reproduce relative to other individuals in the population.

Phenotype and Genotype

Phenotype refers to the traits (outward appearance) of an organism.
Genotype refers to the genetic makeup of an organism.
Phenotype can be shaped by genes, environment, and interaction between genes and environment.
Not all variation within a species is genetically based.

Natural Selection and Mutations

Mutations happen randomly.
Natural selection can only act on existing genetic variation.
Natural selection does not create new variation.
Natural selection can only work with existing variation, which means there are no perfect organisms.
The environment determines whether a mutation conveys an advantage or not.

Adaptation

Organisms are never perfectly adapted to their environment.
There may be constraints on evolution, such as trade-offs or limited environmental resources.
Adaptations may be imperfect because of historical constraints.

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Description

Explore the fundamental concepts of evolution, including microevolution and macroevolution, and understand the mechanisms driving evolutionary change. This quiz delves into the effects of natural selection, genetic variation, and the role of populations in the evolution process.