Biology: Variation Within a Species

Variation Within a Species

• A species is a group of organisms that can interbreed to produce fertile offspring.
• All people belong to the same species, Homo sapiens.
• Variation exists within a species, and it refers to the differences between living organisms of the same species.
• Inherited characteristics, such as height and tongue-rolling, contribute to variation amongst humans.

Environmental Influence

• Animals are adapted to their environment, and individuals with characteristics that make them more successful at surviving will reproduce more and pass on their characteristics to their offspring.
• Environmental changes over time require species to adapt to survive, and if they do not adapt, they may not survive and the species may die out.
• Variation is necessary for species to adapt to their environment.

Classification

• Dogs belong to the kingdom Animalia, phylum Chordata, and class Mammalia.
• Characteristics such as body shape, size, and special features are used to classify organisms.
• Variation within a species does not affect its classification.

How Variation Occurs

• Sexual reproduction produces offspring that are different from the parent organisms, resulting in variation.
• Variation occurs within a species, and even offspring from the same parents can have differences.

Inheritance in Humans

• Certain traits are passed down from generation to generation, from parent organisms to their offspring, through inheritance.
• Traits such as skin colour, height, and tongue-rolling are examples of inherited characteristics.

Natural Selection

• The principle of natural selection refers to the survival of organisms that are best adapted to their environment, leading to the passing on of advantageous characteristics.
• Organisms that are not well adapted to their environment are less likely to survive and reproduce, resulting in the removal of disadvantageous characteristics over time.
• Natural selection is a key mechanism for species to adapt to their environment.

Peppered Moths

• The peppered moths' camouflage helps them hide from predators.
• The dark-coloured moths increased in number after the Industrial Revolution due to the darkening of tree trunks, making them better adapted to their environment.
• The increase in light-coloured moths after improved environmental standards is an example of adaptation to a changing environment.

Learn about variation within a species, how individuals of the same species can reproduce, and the differences between living organisms of the same species.