Genetic Inheritance and Traits

Study Notes

Inheritance of Traits: The passing of characteristics from parents to offspring through genes.
Genotype: The genetic makeup of an individual, including all genes and alleles.
Phenotype: The physical and behavioral characteristics of an individual, resulting from the interaction of genotype and environment.
Dominant and Recessive Alleles: Dominant alleles will always be expressed if an individual has one copy of the allele, while recessive alleles will only be expressed if an individual has two copies of the allele.

Definition: A trait that has evolved to improve an individual's survival and reproduction in a specific environment.
Types of Adaptation:
- Structural Adaptations: Physical traits, such as body shape or color, that aid in survival.
- Physiological Adaptations: Internal traits, such as temperature regulation or immune systems, that aid in survival.
- Behavioral Adaptations: Learned behaviors, such as migration or hibernation, that aid in survival.

Definition: The process by which individuals with favorable traits are more likely to survive and reproduce, passing those traits to their offspring.
Key Components:
- Variation: There must be existing variation in the population for natural selection to act upon.
- Heritability: The traits must be heritable, meaning they are passed down from parents to offspring.
- Differential Survival and Reproduction: Individuals with favorable traits must have a greater likelihood of survival and reproduction.
Types of Natural Selection:
- Directional Selection: Selection favors extreme traits, leading to a shift in the population's average trait value.
- Stabilizing Selection: Selection favors average traits, leading to a reduction in variation.
- Disruptive Selection: Selection favors extreme traits, leading to a split in the population.

Definition: A change in the DNA sequence of an individual, resulting in a new allele.
Types of Mutations:
- Point Mutations: A change in a single nucleotide base.
- Frameshift Mutations: A change in the reading frame of the genetic code, leading to a significantly altered protein.
- Chromosomal Mutations: A change in the number or structure of chromosomes.
Effects of Mutations:
- Neutral: The mutation has no effect on the phenotype.
- Beneficial: The mutation increases the individual's fitness.
- Deleterious: The mutation decreases the individual's fitness.

Inheritance of traits occurs through the passing of genes from parents to offspring.
An individual's genotype refers to their complete genetic makeup, including all genes and alleles.
The phenotype is the physical and behavioral expression of an individual's genotype, influenced by the environment.

Adaptations are traits that have evolved to improve an individual's survival and reproduction in a specific environment.
There are three main types of adaptations:
- Structural adaptations: physical traits (e.g., body shape, color) that aid in survival.
- Physiological adaptations: internal traits (e.g., temperature regulation, immune systems) that aid in survival.
- Behavioral adaptations: learned behaviors (e.g., migration, hibernation) that aid in survival.

Natural selection is the process by which individuals with favorable traits are more likely to survive and reproduce, passing those traits to their offspring.
Three key components are necessary for natural selection to occur:
- Variation: existing variation in the population.
- Heritability: traits must be passed down from parents to offspring.
- Differential survival and reproduction: individuals with favorable traits must have a greater likelihood of survival and reproduction.
There are three main types of natural selection:
- Directional selection: favors extreme traits, leading to a shift in the population's average trait value.
- Stabilizing selection: favors average traits, leading to a reduction in variation.
- Disruptive selection: favors extreme traits, leading to a split in the population.

Mutations are changes in an individual's DNA sequence, resulting in new alleles.
There are three main types of mutations:
- Point mutations: a change in a single nucleotide base.
- Frameshift mutations: a change in the reading frame of the genetic code, leading to a significantly altered protein.
- Chromosomal mutations: a change in the number or structure of chromosomes.
Mutations can have three main effects:
- Neutral: no effect on the phenotype.
- Beneficial: increases the individual's fitness.
- Deleterious: decreases the individual's fitness.

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