B4 - Adaptation, Variation, and Natural Selection

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Questions and Answers

What is the primary source of variation within a species?

Environmental factors

Sexual reproduction (correct)

Mutation rates

Gene flow between populations

What term describes variations that enhance an individual's chances of survival and reproduction?

Adaptations (correct)

Genetic drift

Mutations

Phenotypes

Which type of variation occurs between different species?

Morphological variation

Interspecific variation (correct)

Genetic variation

Intraspecific variation

Which example best illustrates a structural adaptation?

An owl having long talons for catching prey Signup and view all the answers

What is a neutral mutation?

A mutation that has no effect on the organism Signup and view all the answers

What role do heritable mutations play in evolution?

They introduce new genetic material into a population. Signup and view all the answers

How do mutations provide a selective advantage?

They increase chances of survival in changing environments Signup and view all the answers

What defines phylogeny in the context of evolution?

The history of evolution of a group of organisms Signup and view all the answers

What does natural selection result from?

Traits that increase survival to reproductive age Signup and view all the answers

Which process can lead to variations that are passed onto future generations?

Natural selection Signup and view all the answers

What influences whether a trait is selected for or against?

The specific environment at that time Signup and view all the answers

What is an example of a behavioral adaptation?

Geese migrating to warmer climates Signup and view all the answers

Which type of mutation reduces an organism's fitness?

Harmful mutation Signup and view all the answers

What does it mean if a mutation is beneﬁcial?

It enhances the organism's fitness Signup and view all the answers

In what situation are mutations more common?

When the organism's environment is changing Signup and view all the answers

Which scenario best illustrates natural selection?

Environment changes favor certain traits over others Signup and view all the answers

Study Notes

Adaptation, Variation, and Natural Selection

Adaptation is a structural, behavioral, or physiological process that aids survival and reproduction in a particular environment (e.g., camouflage).
Variation in organisms can be observed both between species (interspecific) and within the same species (intraspecific). Variation is crucial for survival.
Variation arises from heritable mutations that confer a selective advantage.
Sexual reproduction fosters variation by combining genetic material from two parents, creating new gene combinations in offspring.
Variations that increase survival and reproduction become more common in a population across generations, becoming adaptations.

Variation

Variations are visible differences among organisms.
Variations are crucial for survival as they allow organisms to adapt to their environment.
Variation can occur between different species (interspecific variation) and within the same species (intraspecific variation).

Variation and Survival

Variation within a species is primarily due to sexual reproduction.
Offspring inherit 50% of their DNA from each parent, producing new combinations of genes and characteristics.
Variations that promote survival and reproduction are passed down to more offspring.
These variations become more common in a population through generations—becoming adaptations over time.

Phylogeny

Phylogeny is the evolutionary history of a species or group of organisms.
It studies how variations arise in the first place.

Adaptations

Adaptation: Structural, behavioral, or physiological processes that aid survival and reproduction.
Structural Adaptations – Physical characteristics, examples include eagle's talons, long legs on a giraffe for reaching high branches
Behavioral Adaptations – An animal's actions—examples: migration (birds, certain insects), hibernation.
Physiological Adaptations – An organism's internal workings—examples: venom production (snakes, spiders), photosynthesis.

Mutations

In order to reproduce, DNA within cell nuclei must replicate and divide.
DNA replication isn't perfect; mistakes occur during replication.
These small genetic code changes are called mutations.
Mutations result in gene expression changes.
Mutations are a source of variation.

Types of Mutations

Neutral mutation – No effect on the organism.
Harmful mutation – Reduces an organism's fitness (likelihood of survival and reproduction).
Beneficial mutation – Enhances an organism's fitness.

Mutations and Selective Advantage

Some mutations produce beneficial changes in individuals.
Mutations that increase an individual's chance of survival are more likely to be passed on to the next generation.
Mutations are more frequent in changing environments.
The resulting mutation can provide a selective advantage in new environments.

Natural Selection

Natural selection is a process where traits that improve an organism's chance of survival to reproductive age are passed down to future generations.
These traits become more common in a population, causing it to evolve over time.

Natural Selection and Environment

Whether a trait is selected for or against depends on the organism's current environment.
Changes in the environment can drive changes in the traits of a population.
Populations adapt to their environment.

Example of Natural Selection (Skin Colour)

Humans need sunlight to absorb Vitamin D.
Harsh UV rays from sunlight damage cells without protection.
Skin colour is an adaptation to environmental pressures (sun exposure).
Individuals with skin colours better absorbing vitamin D in high UV environments are more likely to survive and successfully reproduce.

Artificial Selection

Artificial selection is the process where humans select and breed individuals with desired traits.
Domestic animals and crop plants have been artificially selected over generations.
Artificial selection provides an example of how dramatic evolutionary change can be achieved over relatively short periods.

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Description

Explore the concepts of adaptation, variation, and natural selection in this quiz. Learn how structural, behavioral, and physiological adaptations aid survival, and understand the importance of genetic variation among and within species. Test your knowledge on how these processes drive evolution and species diversity.