Biology Chapter: Adaptations and Variations

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Questions and Answers

What is an example of a structural adaptation?

Sharp talons used for catching prey

Fish producing antifreeze proteins

Thick hair on polar bears for insulation (correct)

Bird migration during winter

How does variation among individuals of the same species occur?

By the mixing of genes during meiosis (correct)

Through genetic mutations alone

Due to environmental changes only

From parental dominance in traits

Which of the following is a behavioral adaptation?

Birds migrating to warmer climates (correct)

Camouflage in chameleons

Changes in skin color in response to temperature

Thick fur on arctic foxes

Which of the following is NOT a requirement for natural selection?

Increased reproductive rates Signup and view all the answers

What type of evidence does the fossil record provide for evolution?

It shows changes in species over time Signup and view all the answers

What is a mutation?

A permanent change in the DNA sequence Signup and view all the answers

Which of the following is an example of a biochemical adaptation?

Fish developing antifreeze proteins Signup and view all the answers

Which disease is associated with gradual brain cell degeneration?

Huntington’s Disease Signup and view all the answers

What evidence supports the idea that species evolved after the breakup of continents?

Species found only in one specific continent. Signup and view all the answers

What is the primary mechanism by which Charles Darwin proposed that species change over time?

Evolution by natural selection. Signup and view all the answers

What kind of features are homologous features?

Similar structures serving different functions. Signup and view all the answers

Which type of isolation occurs when two species breed at different times?

Temporal Isolation. Signup and view all the answers

What does adaptive radiation refer to?

Rapid evolution from a common ancestor. Signup and view all the answers

What does speciation require to occur?

Isolation of populations from each other. Signup and view all the answers

What are vestigial features?

Structures that have lost original functions. Signup and view all the answers

What does the concept of punctuated equilibrium suggest about evolution?

Large changes happen in bursts followed by stability. Signup and view all the answers

What distinguishes analogous features from homologous features?

Similar function, different structure. Signup and view all the answers

Which type of barrier prevents species from interbreeding due to physical separation?

Geographical Barriers. Signup and view all the answers

Study Notes

Adaptations

Adaptations are traits that enhance survival and reproduction.
Biochemical/Body Processes: Internal adaptations like fish producing antifreeze proteins for cold water survival.
Structural Adaptations: Physical traits like polar bear fur for insulation.
Behavioral Adaptations: Actions like bird migration for warmer temperatures.
Examples: Camouflage, hibernation, sharp talons/teeth, good eyesight.

Variations

Variations are differences in traits within a species (size, color, behavior).
Cause of Variations: Mixing of parental genes during meiosis results in unique offspring.
Mutations: Permanent DNA sequence changes.
Examples of Mutations: Tay-Sachs (nerve cell damage), Huntington's (brain cell death), Cystic Fibrosis (lung/pancreas problems).

Natural Selection

Natural selection is how populations change due to survival of individuals with beneficial traits.
Requirements:
Variation in traits within a population.
Selective pressure (environment favoring certain traits).
Heritable traits (passed to offspring).

Evidence for Evolution

Fossils: Provide evidence of species change over time; simpler organisms appear earlier, more complex later, not all species appear at once.
Chronological Order: Fossils in younger layers show more recent species.
Geographic Distribution: Similar species often found in similar geographic areas (evolved after continental separation).
Anatomy:
Homologous Structures: Similar structure, different function (e.g., bat, whale, cat forelimbs), indicating common ancestry.
Analogous Structures: Different structure, similar function (e.g., bird, bat wings), not indicating common ancestry..
Vestigial Structures: Structures with reduced or lost function (e.g., human appendix, whale hip bones).
Transitional Fossils: Fossils showing intermediate stages in evolutionary change.

Lamarck

Lamarck proposed a theory of evolution where acquired traits are inherited.
Example: a giraffe stretching its neck becomes longer in order to survive, and passes this longer neck on.

Darwin

Darwin's theory of evolution by natural selection:
Species change over time because individuals with beneficial traits reproduce more successfully and pass these traits on.
Darwin's work is based on observations made during his voyage on the HMS Beagle.

Speciation

Speciation is the formation of new species.
Types:
Transformation: One species changing completely into a new species.
Divergence: One species splitting into two or more.
For speciation to occur: Populations need to be reproductively isolated to prevent gene flow.
Types of Isolation:
Geographical: Physical barriers preventing interbreeding (mountains, rivers, oceans).
Biological: Internal/behavioral factors preventing interbreeding in the same geography.
Behavioral isolation: differences in mating behaviors.
Habitat isolation: Different habitats even in the same place
Temporal Isolation: Reproductive periods differ.
Mechanical Isolation: Incompatibility of reproductive structures.
Gametic Isolation: Incompatibility of sperm and egg.
Adaptive Radiation: Rapid evolution of many species from a single ancestor (e.g. Darwin's Finches).

Pace of Evolution

Punctuated Equilibrium: Evolution occurs in rapid bursts followed by long periods of little change.
Gradualism: Evolution happens slowly and steadily.

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Description

Explore the concepts of adaptations and variations in biology. Understand how traits can enhance survival through biochemical, structural, and behavioral means. Discover the role of natural selection in shaping populations and the impact of mutations on species traits.