Lesson 9: Biodiversity and Evolution

Summary

This lesson explains the concepts of biodiversity and evolution, focusing on natural selection as the driving force behind species adaptation. It introduces the theory of evolution by Charles Darwin and Alfred Russel Wallace, outlining evidence such as homologous and analogous structures, molecular biology, embryonic development, and biogeographical patterns. The lesson also highlights the fossil record and direct observation of microevolution, such as drug-resistant bacteria. The importance of both macroevolution and microevolution is emphasized, showing how evolutionary processes lead to biodiversity over time.

Takeaways

• 😀 Biodiversity refers to the variety of life on Earth, including species, genetic, and ecosystem diversity.
• 😀 Evolution is the process by which the characteristics of a species change over generations due to natural selection.
• 😀 Natural selection favors individuals that are best suited to their environment, leading to survival and reproduction.
• 😀 Homologous structures are physical features shared by species, suggesting a common ancestor.
• 😀 Vestigial structures are reduced features that no longer serve their original function, like the tailbone in humans.
• 😀 Analogous structures are similar features in species that evolved independently due to similar environments or pressures.
• 😀 Molecular biology shows that all living organisms share genetic material (DNA), which supports the idea of common ancestry.
• 😀 Species that are closely related show similar embryonic development, even when they look different as adults.
• 😀 Biogeographical patterns reveal how species are distributed across the Earth, providing clues to their evolutionary history.
• 😀 The fossil record provides evidence of species that existed in the past, helping us understand evolutionary processes.
• 😀 Direct observation of microevolution, like antibiotic-resistant bacteria, allows us to witness evolution in real time.

Q & A

What is biodiversity, and why is it important?

Biodiversity refers to the variety of life on Earth, including species diversity, genetic diversity within species, and ecosystem diversity. It is important because it contributes to the resilience of ecosystems, supports ecosystem services, and maintains the balance of life on the planet.

How does evolution occur according to Charles Darwin's theory?

Evolution occurs through the process of natural selection, where individuals in a species exhibit variations in their traits. Those with traits better suited to their environment are more likely to survive and reproduce, passing those beneficial traits to the next generation.

What is the difference between macroevolution and microevolution?

Macroevolution refers to large-scale changes that occur over extended time periods, such as the formation of new species. Microevolution involves small-scale changes that affect a few genes and occur in populations over shorter time frames.

What are homologous structures, and what do they indicate?

Homologous structures are physical features shared by different species, inherited from a common ancestor. These structures may look different in appearance but have similar underlying bone patterns, indicating a shared evolutionary history.

What are vestigial structures, and can you provide an example?

Vestigial structures are physical features that have lost their ancestral function over time. An example is the human tailbone, which is a remnant of a tail found in our evolutionary ancestors.

What is the concept of analogous structures in evolution?

Analogous structures are physical features in different species that serve similar functions but evolved independently, not from a common ancestor. An example is the wings of birds, bats, and insects, all used for flight but developed in separate lineages due to similar environmental pressures.

How does molecular biology provide evidence for evolution?

Molecular biology shows that all living organisms share common features, such as DNA as genetic material, similar genetic codes, and molecular building blocks like amino acids. These shared features suggest that all organisms are descended from a common ancestor.

What does embryonic development reveal about species relatedness?

Embryonic development shows that closely related species often have similar stages in their early development, even though they may appear very different as adults. This supports the idea that they share a common ancestor.

How do biogeographical patterns support the theory of evolution?

Biogeographical patterns show how species are distributed across the planet in ways that reflect their evolutionary history. For example, species that evolved before the breakup of the supercontinent Pangaea are found worldwide, while those that evolved after the breakup are often confined to smaller regions.

What is an example of direct observation of microevolution?

An example of direct observation of microevolution is the emergence of antibiotic-resistant bacteria. Over time, bacteria can evolve resistance to drugs like antibiotics, showing how evolution can occur within short time spans.