Question

According to Darwin, a. the adapted individual is the one who survives and passes on its genes to offspring. b. changes in phenotype are passed on by way of the genotype to the next generation. c. organisms are able to bring about a change in their phenotype. d. evolution is striving toward particular traits. e. All of these are correct.

Short answer

The correct answer is a combination of statements a and b, which state that the adapted individual is the one who survives and passes on its genes to offspring, and changes in phenotype are passed on by way of the genotype to the next generation.

Step-by-step solution

Understand Darwin's theory of evolution and natural selection

According to Darwin, evolution occurs through a process called natural selection. Organisms with traits that are better suited to their environment are more likely to survive and reproduce, passing on their advantageous traits to their offspring. Over time, these traits become more common in the population, leading to the evolution of the species. With this understanding, let's examine each statement.

Analyze statement A

"The adapted individual is the one who survives and passes on its genes to offspring." This statement is in line with Darwin's theory. Organisms with adaptations that are advantageous in their environment are more likely to survive and pass these traits onto their offspring. So, statement A is accurate.

Analyze statement B

"Changes in phenotype are passed on by way of the genotype to the next generation." Phenotype refers to an organism's observable traits, while genotype refers to its genetic makeup. This statement is also accurate, as changes in an organism's phenotype (traits) are a result of changes in its genotype, which can be passed on to future generations.

Analyze statement C

"Organisms are able to bring about a change in their phenotype." This statement is not accurate in the context of Darwin's theory. Organisms cannot directly change their phenotype in response to environmental pressures. Instead, genetic variations that arise due to mutations or sexual reproduction lead to variations in phenotype, and natural selection acts upon these variations.

Analyze statement D

"Evolution is striving toward particular traits." Darwin's theory of evolution does not suggest that evolution has a specific goal or direction and is not striving for particular traits. Natural selection acts on variations in traits that arise through genetic mutation and sexual reproduction. Therefore, statement D is not accurate.

Evaluate statement E

"All of these are correct." Since statements C and D are not accurate, statement E is not correct. In conclusion, the correct answer is: a. The adapted individual is the one who survives and passes on its genes to offspring. b. Changes in phenotype are passed on by way of the genotype to the next generation.

Key concepts

Understanding Natural Selection

Natural selection serves as a cornerstone in Darwin's theory of evolution. It is a process through which organisms with traits that enhance their survival and reproductive success tend to pass on these advantageous characteristics to their offspring. Over generations, these traits can become more prevalent within a population, leading to evolutionary change.

For example, imagine a species of birds in an area where insects constitute the primary food source. Birds with beaks better shaped for catching these insects are more likely to thrive and reproduce. Consequently, the trait for the advantageous beak shape is naturally selected and becomes more common in future generations.

It's important to note that natural selection is not a conscious choice by the organisms but a natural consequence of the variations within a population. While it may seem like natural selection is 'choosing' the best traits, it is simply an outcome of which individuals manage to survive and reproduce under given environmental conditions.

Genotype and Phenotype Explained

Understanding the difference between genotype and phenotype is fundamental in grasping how traits are inherited and expressed in organisms. The genotype of an individual is its specific genetic makeup, composed of DNA sequences called genes. In contrast, the phenotype is the observable expression of these genes - the traits you can see, like hair color, height, or beak shape in birds.

In essence, the genotype is like a recipe that determines what the phenotype will be, although the environment also plays a role in how these traits are ultimately expressed. For instance, identical twins (with the same genotype) can have different heights (different phenotypes) if one has a diet rich in nutrients and the other does not.

The Inheritance of Traits

The inheritance of traits from parents to offspring occurs through the passing of genotypes. During reproduction, genes from both parents are inherited by the offspring, which combines to form its unique genotype. This genetic blueprint will dictate the potential phenotypes the offspring may express, subject to environmental influences.

Genes can be dominant or recessive, which affects how traits are inherited. For example, if a trait is governed by a dominant gene, only one copy of that gene is needed for the trait to be expressed in the phenotype. Recessive traits require two copies, one from each parent, for the trait to be manifested.

It's important to note that traits are not inherited as individual units, but rather as part of chromosomes that carry many genes. The complex interaction between different genes can lead to a wide variety of phenotypic expressions, contributing to the diversity observed within species.