EVOLUTION_AND_INHERITANCE_MUTATION-1[1] Flashcards
What is the phenotype of a flower?
The flower color
Phenotype refers to the observable traits of an organism.
What does the capital W signify in genetics?
The dominant purple allele
Alleles are different forms of a gene.
What does a lowercase w represent?
The recessive white allele
A recessive allele is only expressed when two copies are present.
What genotype results in a purple flower?
Either two capital Ws or one capital W and one lowercase w
Genotypes determine phenotypes based on allele combinations.
What genotype results in a white flower?
Two lowercase ws
This is an example of a homozygous recessive condition.
What is genetic variance?
The variation in heritable traits among individuals in a population
It is crucial for natural selection to act upon.
How do natural selection and evolutionary forces act on traits?
They act on heritable traits, not acquired traits
Acquired traits cannot be passed to offspring.
What is heritability?
The extent to which phenotypic variation in a population is due to genetic differences
It measures how traits are passed from parents to offspring.
What is linkage disequilibrium?
The tendency for alleles that are physically close on a chromosome to be inherited together
This can affect the outcomes of genetic selection.
What is the fitness of an organism?
The net effect of its alleles on survival and reproduction
Fitness determines how well an organism can pass its genes to the next generation.
Can natural selection produce a perfect organism?
No, it can only select from existing variation
Natural selection cannot create new traits but acts on what is available.
What is genetic drift?
The random elimination of alleles from a population due to chance events
It can lead to significant changes in small populations.
How does genetic drift affect small populations?
Small populations are more susceptible to genetic drift
A single individual’s death can significantly impact the gene pool.
What is gene flow?
The transfer of alleles in and out of a population due to migration
It introduces new genetic variation to populations.
What is the bottleneck effect?
A sharp reduction in population size leading to a loss of genetic diversity
It can occur due to environmental events or human activities.
What is sexual dimorphism?
Differences in size or appearance between males and females of the same species
It often arises from differing reproductive strategies.
What is stabilizing selection?
Natural selection that favors average phenotypes and selects against extremes
It reduces genetic variance in a population.
What is directional selection?
Natural selection that favors phenotypes at one end of the spectrum
It can lead to shifts in population traits over time.
What is diversifying selection?
Natural selection that favors two or more distinct phenotypes
It can maintain multiple forms within a population.
What is frequency-dependent selection?
Selection that favors common or rare phenotypes depending on the situation
It can lead to cyclical changes in phenotype distributions.
What defines a population in biological terms?
A group of organisms of the same species found in the same area that can interbreed
It is the smallest unit that can evolve.
What is mutation?
Any change in the DNA sequence of a cell
Mutations can be caused by errors in DNA replication or environmental factors.
What are inherited mutations?
Gene mutations passed from parents to offspring through egg or sperm
They can lead to hereditary conditions like cystic fibrosis.
What is a mutation?
A change in DNA, the hereditary material of life
Mutations can be harmful, beneficial, or have no effects.
What happens if a parent carries a gene mutation?
The mutation can be passed to their child, resulting in hereditary mutations present in almost every cell of the child’s body
Examples include cystic fibrosis, hemophilia, and sickle cell disease.
According to de Vries’ mutation theory, what can living organisms develop?
Changes to their genes that greatly alter the organism
These changes can lead to the development of new species.
How does mutation contribute to evolution?
Mutation generates the genetic variation on which the evolutionary process depends.
What is an allele?
A version of a gene that controls a particular feature of an organism.
What is a genotype?
A plant’s set of alleles.
What is a phenotype?
Observable features of an organism, determined by its genotype.
What is microevolution?
The change in allele frequencies within a population over time.
What processes contribute to microevolution?
Mutation, selection (natural and artificial), gene flow, gene migration, and genetic drift.
What distinguishes microevolution from macroevolution?
Microevolution happens over a relatively short time compared to macroevolution, which involves greater changes and occurs over long periods.
What is population genetics?
The field of biology that studies allele frequencies in populations and how they change over time.
What did Gregor Mendel discover about trait inheritance?
Traits are specified by non-blending heritable units called genes.
What is the blending inheritance model?
A model where parents’ traits are supposed to permanently blend in their offspring.
What does ecological genetics study?
Observing microevolution in the wild.
What is an example of a condition inherited through autosomal recessive inheritance?
Sickle cell disease.
Fill in the blank: Mutation is the raw material of _______.
genetic variation.
What is the connection between microevolution and speciation?
Microevolution over time leads to speciation or the appearance of novel structures.
True or False: Darwin was aware of the genetic basis of heritable traits.
False.
What does the term ‘macroevolution’ refer to?
Evolution that involves large changes, such as the formation of new groups or species.
What is an example of observable microevolution?
Bacterial strains that have antibiotic resistance.
