The theory of common descent states that all modern organisms
a. Can change in response to environmental change
b. Descended from a single common ancestor
c. Descended from one of many ancestors that originally arose on Earth
d. Have not evolved
e. Can be arranged in a hierarchy from 'least evolved' to 'most evolved'

Verified step by step guidance

1. Understand the concept of the theory of common descent: This theory is a fundamental principle of evolutionary biology, which states that all living organisms share a common ancestor from which they have evolved over time.
2. Analyze the options provided: Carefully read each option and determine whether it aligns with the concept of common descent. For example, consider whether the option implies a shared ancestry or something unrelated to evolutionary theory.
3. Eliminate incorrect options: For instance, options like 'have not evolved' or 'can be arranged in a hierarchy from least evolved to most evolved' are inconsistent with the principles of evolution and common descent.
4. Focus on the correct interpretation: The theory of common descent specifically emphasizes that all modern organisms descended from a single common ancestor, which is a key point in evolutionary biology.
5. Select the correct answer: Based on the analysis, identify the option that best aligns with the theory of common descent, which is 'descended from a single common ancestor.'

Key Concepts

Theory of Common Descent

The theory of common descent posits that all living organisms share a common ancestor from which they have evolved over time. This concept is fundamental to evolutionary biology, as it explains the diversity of life on Earth through the process of descent with modification. It suggests that species are not static but rather dynamic entities that adapt and change in response to environmental pressures.

Evolution

Evolution is the process through which populations of organisms change over generations, driven by mechanisms such as natural selection, genetic drift, and mutation. It leads to adaptations that enhance survival and reproduction in specific environments. Understanding evolution is crucial for interpreting the relationships among species and the evidence supporting the theory of common descent.

Phylogenetic Tree

A phylogenetic tree is a diagram that represents the evolutionary relationships among various biological species based on their genetic or physical characteristics. It illustrates how species diverged from common ancestors over time, providing a visual framework for understanding the hierarchy of life. This concept is essential for grasping the implications of common descent and the interconnectedness of all living organisms.