The main difference between dimorphism and polymorphism is that dimorphism means having two forms, whereas polymorphism means having different forms with discrete variations.
Dimorphism and polymorphism are two types of variations of characters. Monomorphism has only one form.
Key Areas Covered
1. What is Dimorphism
– Definition, Facts, Features
2. What is Polymorphism
– Definition, Facts, Features
3. Similarities Between Dimorphism and Polymorphism
– Outline of Common Features
4. Difference Between Dimorphism and Polymorphism
– Comparison of Key Differences
5. FAQ – Dimorphism and Polymorphism
– Answers to frequently asked questions
Key Terms
Dimorphism, Polymorphism
What is Dimorphism
Dimorphism is the presence of two characters for a particular trait. Dimorphic characters inherited through sexual dimorphism are an example of dimorphism. It is the presence of two sexes, male and female, within a species. Male and female organisms differ from each other in color, shape, size, and structure. Also, extreme differences, such as adaptations for sexual dimorphism, can occur. Birds show at least a single character for sexual dimorphism. Colors of the male bird and exotic plumes are such adaptations. Moreover, in male baboons, adaptations such as great size and huge canine teeth occur for their protection. Generally, male organisms show courtship and territorial behavior.
Figure 1: Sexual Dimorphism
Furthermore, size differences can occur between the two sexes. For example, male baboons are two times larger than female baboons. However, in mammals, the female sex is larger than the male.
What is Polymorphism
Polymorphism refers to the occurrence of more than one type of organism in the same species, which have the same locality. Genetic variation causes the phenotypic variation of organisms of the same species within a population. Different forms of individuals of the same species occur due to discontinuous genetic variation. The discontinuous genetic variations produce two or more sharply distinct forms within a population. When a mutation produces a different form of the individual, it is recognized as another ‘morph’ only if the occurrence of that particular individual is too high within the population.
Figure 2: Light-spotted Jaguar
For example, different blood types of humans are another example of polymorphism. In contrast, in the continuous genetic variation, slight variations occur within the population, producing various phenotypes. The variation in the height of individuals in the human population is an example of continuous genetic variation.
Similarities Between Dimorphism and Polymorphism
- Dimorphism and polymorphism are two variation types that occur in organisms.
- Different morphs or forms occur in the form of phenotypes in the population.
- The next generation inherits them through genetic material.
Difference Between Dimorphism and Polymorphism
Definition
Dimorphism refers to the occurrence or representation of two distinct forms. In contrast, polymorphism refers to the occurrence of different forms among the members of a population or colony, or in the life cycle of an individual organism.
Number of Forms
Dimorphism means having two forms, while polymorphism means having difference forms with discrete variation.
Examples
An example of dimorphism is the presence of two sexes in most organisms, while examples of polymorphism are mimetic forms of butterflies, human hemoglobin, and blood types.
FAQ: Dimorphism and Polymorphism
What is the difference between polymorphism and polyphenism?
Polymorphism is heritable and modified by selection. In contrast, in polyphenism, environmental conditions determine the expression of different morphs.
What is an example of a polymorphism in animals?
Jaguars have more than one trait, for example, their skin color is an example of polymorphism. They occur in both dark and white spots.
Why is polymorphism important in zoology?
In biology, polymorphism or discontinuous genetic variation results in the occurrence of different types of individuals within a single species. Therefore, the discontinuous genetic variation divides individuals in a population into two or more sharply distinct forms.
Conclusion
In brief, dimorphism and polymorphism are two types of variations that occur in living organisms. Dimorphism is the presence of two forms for a particular character. Sexual dimorphism is an example of dimorphism. In contrast, polymorphism is the presence of more than two forms for a particular character. Mimetic forms of butterflies, and human hemoglobin and blood types are examples of polymorphism. Therefore, the main difference between dimorphism and polymorphism is the number of variations occurring for a particular character.
References:
- Encyclopædia Britannica, inc. (n.d.-b). Martin Luther King, jr., 1929–68. Encyclopædia Britannica.
Image Courtesy:
- “Pair of mandarin ducks” By en:User:Cburnett – Own Work (CC BY SA 3.0) via Commons Wikimedia
- “Jaguar head shot” By Francis C. Franklin (CC BY SA 3.0) via Commons Wikimedia
Leave a Reply