Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
|
|

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying

Phenotypic Frequencies

Phenotypic Frequencies

As you may already know, the genes found in an organism make up its genotype. The genotypes organisms are inherited from their parents. Genes can help determine the physical attributes of an organism, and these visible physical attributes are known as a phenotype. These attributes include traits such as hair color, eye color, height, and wing length. These phenotypes that make up populations are able to be broken up into fractions. Each fraction represents a different physical feature and how common it is in the population. This is known as phenotypic frequency.

Phenotypic frequencies definition

Phenotypic frequencies are the number of organisms in a population with a certain observable trait. This does not take into account alleles that are recessive and are not physically visible.

Alleles are variations of the DNA sequence inherited from an organism's parents. Organisms always have two alleles for each gene, determining its traits.

Phenotypic frequencies properties

Remember, phenotypes are the visible traits seen in an organism, so there are numerous examples of phenotypes. Alongside visible traits like height, eye color, and hair color, there are also behavioral phenotypes.

Behavioral phenotypes consist of cognitive, personality, and behavioral patterns. Examples of these can be self-injury, screaming, and aggression. However, there is much debate between scientists on whether or not a disorder falls into a behavioral phenotype. For example, some scientists will categorize certain disorders as behavioral phenotypes without having genetic anomalies.

A more well-known form of behavioral phenotypes is displayed in dogs. For example, each dog breed was bred to perform a different task. Even if they were never trained for herding, some herding dogs, such as Border Collies, have been known to round up objects or even their owners as if they were herding sheep.

Phenotypic examples

Using an example of a fly's wings for our phenotype, we can clearly see how phenotypes and genotypes work together. Figure 1 below shows that flies that have ww alleles will be homozygous recessive and have clearly wrinkled wings. Any other fly will have visibly normal wings due to either having the dominant W allele. Remember, we do not count the alleles when determining phenotypes, and we only look at physical qualities (e.g., whether or not the wings are wrinkled).

Phenotypic Frequencies Phenotypes of Fly Wings StudySmarterFigure 1. Flies wing appearance and their genotypes. Source: National Human Genome Research Institute via commons.wikimedia.org

Phenotypic frequencies formula

There is a formula that can be used to assess the phenotypic frequencies of a population.

The formula is:

Phenotypic frequencies formula examples

Let's say that we have an assortment of twenty roses that come in various colors. We have five red roses, eight white roses, and seven pink roses. What is the phenotypic frequency for each color of rose?

We can begin by finding the phenotypic frequency for the red roses.

This shows that a quarter of this rose population is red.

Next, let's solve for the phenotypic frequencies of white roses.

This shows that two-fifths of the population is white.

Finally, let's look at the phenotypic frequency of pink roses.

This shows that three-twentieths of the rose population is pink.

Remember, your answers for each phenotypic frequency should be able to be added together to equal one. This is a good way to check your work! Also, if you ever need your phenotypic frequencies in the form of a percentage, you can just multiply them by 100.

Let's try another example! This time we have frogs, and there is 456 total. 180 are solid green, 100 are green with spots, 150 are yellow, and 26 are yellow with spots. What are the phenotypic frequencies of each frog coloration?

Let's start by finding the frequency for the solid green frogs.

The phenotypic frequency is fifteen-thirty-eighths. This will be our largest phenotypic frequency for this example.

Next, let's find the frequency for green frogs with spots.

Now, let's find the phenotypic frequency for yellow frogs that do not have spots.

Finally, we can solve for the number of frogs that are yellow with spots.

Once we finish finding all of the phenotypic frequencies, we can add them all together to make sure they add up to 1.

What is the difference between phenotypic frequencies and allele frequencies?

There are many differences between phenotypic and allele frequencies, and these mainly come from alleles and phenotypes being somewhat related, but still very different things. Phenotypes are the visible traits of an organism, while alleles are forms of a gene that determine the visible traits of an organism. Alleles will count each form of a gene, while phenotypes count only the visible qualities. For example, in a species of flower, there is the dominant allele B and the recessive allele b. Homozygous dominant and heterozygous flowers are purple, but homozygous dominant are white. Alleles will count the total numbers of B and b in order to find allele frequency, but phenotypic frequency only accounts for the visible colors. You can see an example of this in Figure 2 below.

Phenotypes can also be known as traits, while alleles can also be known as genotypes. Alleles can only be found in the loci of chromosomes.

Loci are the physical locations of genes on a chromosome. Locus is the singular form.

Phenotypic Frequencies Flower Alleles Phenotypes StudySmarterFig. 2. Flower alleles vs phenotypes.

Differences between genotypes and phenotypes

Genotypes are an organism's entire genetic code, while phenotypes are just the expressed traits from this genetic code. As mentioned previously, phenotypes can be altered by the environment, but genotypes cannot, because it is inherited information from an organism's parents.

Even identical twins with the same genotypes can have different phenotypes! This is due to the impact the environment plays on phenotypes. The environment can affect phenotypes via diet, temperature, light cycles, oxygen levels, humidity, and mutagens. One example of temperature affecting phenotypes involves Siamese cats. Siamese cats have a coloring that changes based on whether or not they are exposed to cold temperatures. The coldest parts of the cats, such as their ears, paws, nose, and tail, begin to collect a darker pigment than the rest of their body. You can see an example of a Siamese cat in Figure 3 below.

Phenotypic Frequencies Siamese Cat StudySmarterFigure 3. An example of a Siamese cat's coloration and how temperature has impacted it.

Why do we want to study phenotypic frequencies?

Scientists like to study phenotypic frequencies to see the prevalence of traits within a population over time. For example, they can see if potential gene mutations or genetic drift have occurred over time, and they can also assess the genetic diversity within a population. Also, they can try and predict what traits future generations will have. Recent studies have also shown that phenotypic frequencies can aid in adapting to new or fluctuating environments. Phenotypic frequencies can also aid in the agricultural industry by speeding up the harvesting of crops with similar size, ripeness, and shape phenotypes.

Genetic drift is the way a gene's frequency in a population can change over time due to chance.

Phenotypic Frequencies - Key takeaways

  • Phenotypes are the visible traits of an organism.
  • Organisms get their phenotypes from their genes.
  • Some examples of phenotypes are height, hair color, eye color, and wing length.
  • Phenotypic frequencies assess how popular a specific trait is in the population.
  • The formula for phenotypic frequency is: .

Frequently Asked Questions about Phenotypic Frequencies

No, allele frequencies assess all alleles, and phenotype frequencies assess only physical features.

A genotype is all of the genes found in an organism while a phenotype is only the physical characteristics of an organism. 

Phenotype frequency can be computed by dividing the number of individuals with the specific phenotype by the total population 

Phenotypes are observable properties such as appearance, development, and behavior. 

Phenotypic frequencies is the portion of individuals in a population displaying a specific trait.

Final Phenotypic Frequencies Quiz

Question

What is a phenotype?

Show answer

Answer

A phenotype is the visible traits of an organism

Show question

Question

How do organisms get their phenotypes?

Show answer

Answer

They get them from their genotypes and the environment

Show question

Question

What is a phenotypic frequency? 

Show answer

Answer

The number of organisms in a population with the observable trait

Show question

Question

What are examples of phenotypes?

Show answer

Answer

Blood types

Show question

Question

Behavior is also considered a phenotype.

Show answer

Answer

True

Show question

Question

Alleles help create phenotypes.

Show answer

Answer

True

Show question

Question

Can identical twins with identical genotypes have different phenotypes?

Show answer

Answer

Yes

Show question

Question

What are the environmental impacts on phenotypes? 

Show answer

Answer

The environment can affect phenotypes via diet, temperature, light cycles, oxygen levels, humidity, and mutagens.

Show question

Question

Why do we want to study phenotypic frequencies?

Show answer

Answer

To study the prevalence of traits in a population over time

Show question

Question

What is the difference between phenotypic frequency and allele frequency? 

Show answer

Answer

A genotype is all of the genes found in an organism while a phenotype is only the physical characteristics of an organism. 

Show question

Question

What is the difference between phenotypes and genotypes?

Show answer

Answer

Phenotypes are the visible traits in an organism and genotypes are all of the genes found in an organism 

Show question

Question

What are alleles? 

Show answer

Answer

Variations of the DNA sequence inherited from an organism's parents.

Show question

Question

Phenotypes and alleles can both be seen with the naked eye.

Show answer

Answer

False

Show question

Question

Both phenotypes and genotypes can be altered by the environment.

Show answer

Answer

False

Show question

60%

of the users don't pass the Phenotypic Frequencies quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.