Question

Match each term with the most suitable description. $$ \text {lineage} \quad \quad \text {a. does not affect fitness} $$ $$ \text {fossils } \quad \quad \text {b. line of descent} $$ $$ \text {natural selection} \quad \quad \text {c. human arm and bird wing} $$ $$ \text {neutral mutation } \quad \quad \text {d. survival of the fittest} $$ $$ \text {half-life} \quad \quad \text {e. characteristic of a radioisotope} $$ $$ \text {homologous structures } \quad \quad \text {f. insect wing and bird wing} $$ $$ \text {analogous structures} \quad \quad \text { g. evidence of ancient life} $$

Short answer

b, g, d, a, e, c, f

Step-by-step solution

Match 'lineage'

The term 'lineage' refers to a line of descent, or the genetic heritage of an organism. Connecting it to 'b. line of descent,' we see this is the correct match.

Match 'fossils'

Fossils are remnants or impressions of ancient organisms preserved in rock. They provide 'g. evidence of ancient life.' So, 'g' is the correct description for 'fossils.'

Match 'natural selection'

Natural selection is the process where organisms better adapted to their environment tend to survive and reproduce more successfully. This is often summarized as 'd. survival of the fittest.' Thus, 'd' matches with 'natural selection.'

Match 'neutral mutation'

A neutral mutation is a genetic change that does not affect the fitness of an organism. The corresponding description is 'a. does not affect fitness,' making 'a' the match for 'neutral mutation.'

Match 'half-life'

Half-life is the time required for half of a quantity of a radioisotope to decay. This is the 'e. characteristic of a radioisotope,' making 'e' the correct match for 'half-life.'

Match 'homologous structures'

Homologous structures, like the human arm and bird wing, share a common ancestry. They correspond to 'c. human arm and bird wing,' so 'c' is the match for 'homologous structures.'

Match 'analogous structures'

Analogous structures, such as insect wings and bird wings, perform similar functions but do not share common ancestry. This is 'f. insect wing and bird wing,' making 'f' the match for 'analogous structures.'

Key concepts

Lineage

Lineage refers to the ancestral line or genealogy of an organism. It traces the family tree of living beings from one generation to the next. This concept is crucial in understanding evolution, as it shows how species are connected through a series of ancestral forms. By tracing lineage, scientists can reconstruct the evolutionary paths of organisms. For example, the lineage of humans can be followed back to primates, showcasing the shared ancestry across different species. Understanding lineage helps us appreciate the genetic heritage passed on through various forms of life.

Fossils

Fossils are the preserved remains or impressions of ancient life forms found in sedimentary rock. They are invaluable to scientists as they provide direct evidence of life from millions of years ago. Fossils help understand the morphology of extinct organisms and offer insights into past ecosystems. By studying fossils, paleontologists can piece together the history of life on Earth:

• They provide clues about the organism's environment.
• They help to construct timelines for evolutionary events.
• They provide insight into how species have adapted over time.

Fossils serve as a window into the past, helping paint a picture of evolution across lengthy geological periods.

Natural Selection

Natural selection is a fundamental mechanism of evolution, described famously by Charles Darwin. It operates on the principle of "survival of the fittest," where organisms that are better adapted to their environment tend to survive and reproduce more successfully. This process leads to the gradual adaptation of species in correlation to environmental pressures. Key features of natural selection include:

• Variation in traits: Organisms show variations in traits, and those traits can affect survival.
• Heritability: Survivable traits are passed on to future generations.
• Reproductive success: Those better suited to the environment reproduce more effectively.

Natural selection explains how species evolve to become well-suited for their niches over generations.

Neutral Mutation

Neutral mutations are changes in DNA that do not affect an organism's fitness. Unlike advantageous or deleterious mutations, neutral mutations neither improve nor hinder reproductive success. They are crucial for understanding genetic variation within populations. Over time, neutral mutations accumulate, and they serve as markers for tracing lineage connections. These mutations also provide insight into molecular evolution by indicating genetic drift's impact.
Because neutral mutations don't affect survival, they can become widespread across a population without selection pressure. They highlight the role of random changes in the genetic makeup of organisms.

Half-Life

Half-life refers to the time it takes for half of a given amount of a radioactive substance to decay. It's a constant rate and is used to date materials in fields like archaeology and geology. Understanding half-life is essential for radiometric dating, which determines the age of fossils and rocks. This method helps scientists ascertain the timeline of evolution and major geological events.

• Half-life can range from fractions of a second to billions of years, depending on the isotope.
• Radioactive isotopes like Carbon-14 are used for dating more recent artifacts.
• Isotopes like Uranium-238 date older geological formations.

Half-life thus provides a "clock" for dating ancient materials, helping us track the history of life.

Homologous Structures

Homologous structures are anatomical features that different organisms share due to common ancestry. Despite performing different functions, these structures have a similar underlying anatomy. A classic example is the forelimbs of humans and birds, which reflect evolutionary histories. Homologous structures are key evidence of evolutionary relationships, as they demonstrate shared lineage and divergence:

• They reveal how different species adapt to various environments while retaining a common trait.
• They show the evolutionary process of descent with modification.
• They support the concept of a common ancestor among species.

Understanding homologous structures enhances our appreciation of the intricate web of life, illustrating evolution's influence over shared genetic history.

Analogous Structures

Unlike homologous structures, analogous structures arise from convergent evolution. These are features in different species that have similar functions but do not originate from a common ancestor. An example is the wings of insects and birds, which evolved independently to aid in flight. These structures highlight how different organisms can evolve similar traits in response to comparable environmental challenges.
Analogous structures signify that similar selection pressures can result in equivalent adaptations across unrelated lineages. They emphasize the importance of adaptation in evolutionary biology and illustrate the concept of multiple paths leading to similar biological solutions.