Question

If evolution occurs, we would expect different biogeographical regions with similar environments to a. contain the same mix of plants and animals. b. each have its own specific mix of plants and animals. c. have plants and animals with similar adaptations. d. have plants and animals with different adaptations. e. Both b and c are correct.

Short answer

The correct answer is e. Both b and c are correct, as they are consistent with the concept of evolution. Different biogeographical regions with similar environments would each have its own specific mix of plants and animals (b), as well as have plants and animals with similar adaptations (c) due to convergent evolution.

Step-by-step solution

Understand the concept of evolution

Evolution is the process by which species of organisms change over time due to genetic variation, adaptation to their environments, and natural selection. This process leads to the emergence of new species and the extinction of others.

Evaluate each choice in the context of evolution

a. Contain the same mix of plants and animals: This choice would suggest that there is no variation in species across regions, which goes against the concept of evolution. Therefore, this choice is incorrect. b. Each have its own specific mix of plants and animals: This choice suggests that evolution would lead to unique and distinct species in different geographical regions. This choice is consistent with the concept of evolution and can be considered as a potentially correct answer. c. Have plants and animals with similar adaptations: This choice suggests that species in similar environments would develop similar adaptations through the process of evolution, even if they are geographically isolated from each other. This is known as convergent evolution, and this choice is also in line with the concept of evolution. d. Have plants and animals with different adaptations: This choice goes against the concept of evolution, as species in similar environments would be expected to develop similar adaptations to survive and thrive. e. Both b and c are correct: Since both choices b and c are consistent with the concept of evolution, this choice can also be considered as a possible correct answer.

Select the correct answer

After evaluating each choice, we can conclude that the correct answer is: e. Both b and c are correct.

Key concepts

Biogeography

Biogeography is a fascinating field that explores the distribution of living organisms over geographical areas and through geological time. It's a study that combines elements of ecology, geography, and evolutionary biology to understand the patterns and factors that underlie the ranges of species and how these have shifted over time due to environmental changes and the evolutionary process.

Multiple factors influence these patterns including continental drift, climate change, the emergence of physical barriers like mountains and rivers, as well as human activities. When we look at different biogeographical regions, we often find that each region has its own specific mix of plants and animals, which is a direct result of the evolutionary history unique to that area. This distinctive composition is why you'll find kangaroos in Australia but not in Africa, and why cacti are common in the deserts of North America but not in the Sahara.

Natural Selection

Natural selection is one of the core mechanisms of evolution, postulated by Charles Darwin. It explains how certain traits become more common in a population over time if they contribute to an organism's survival and reproductive success. The essence of natural selection lies in the fact that individuals with beneficial traits, even tiny differences, are more likely to survive and pass on these traits to their offspring.

Imagine a population of beetles with various shell colors. If birds can easily spot and eat beetles with brighter shells, the ones with dark shells that blend in with the environment might survive longer and reproduce more. Over time, the population would have more dark-shelled beetles — that's natural selection in action. This process works hand in hand with genetic variation, leading to the evolution of new species adapted to their environments.

Convergent Evolution

Convergent evolution occurs when species from different evolutionary branches develop similar features independently, usually because they live in similar environments or face similar ecological challenges. It's like arriving at the same destination from different starting points.

For instance, sharks and dolphins have similar body shapes, which help them move efficiently through the water, yet sharks are fish while dolphins are mammals. Their similar forms are not due to shared ancestry but to convergent evolution driven by the need to streamline movement in water. This is a clear illustration of how similar environmental pressures can lead to similar adaptations in species from distinct evolutionary pathways.

Genetic Variation

Genetic variation is the diversity in DNA sequences among individuals within a population. It is the raw material for evolution. Variations can arise from mutations, gene shuffling during reproduction, and the immigration of new individuals into a population bringing novel genes with them. Without genetic variation, natural selection would have no material to work on; there would be no adaptability to changing environments, and ultimately, no evolution.

Variation enables populations to have different characteristics, and over time, these variations can accumulate, leading to the distinct differences we see across biogeographical regions. The rich tapestry of life currently present on earth is all thanks to the multitude of genetic variations that have occurred over the millennia.