Evolutionary Biology: Key Concepts

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Questions and Answers

Which characteristic of Pakicetus provides strong evidence linking it to whale evolution?

Its unique inner ear shape featuring an enhanced auditory bulla, similar to modern whales. (correct)
The presence of heavy ribs, implying an ability to live both on land and in water.
Its four legs suggest a semi-aquatic lifestyle, connecting it to early marine mammals.
Its relatively small size indicating a transition from larger land mammals.

How does the fossil Tiktaalik roseae contribute to our understanding of evolutionary history?

It demonstrates the development of flippers in early aquatic mammals.
It provides evidence for the earliest relatives of enormous whales being small land mammals.
It represents a direct ancestor of modern sea cows and manatees.
It exemplifies the transition of vertebrate life from aquatic to terrestrial environments. (correct)

Pezosiren portelli is considered a transitional form for what reason?

It exhibits a blend of traits from land mammals and fully aquatic sirenians. (correct)
It demonstrated the transition from water to land.
It shows the process of enhancing desirable traits in plants and animals through selective breeding over generations.
It had a unique inner ear shape similar to modern whales.

What is the primary mechanism behind artificial selection?

The identification and perpetuation of desirable traits in organisms by humans. (D) Signup and view all the answers

The diversity of species across different geographic locations is best explained by which combination of factors?

Evolutionary processes and the movement of tectonic plates over geological time. (D) Signup and view all the answers

If a novel flowering plant with tube-shaped flowers is discovered in Northern Europe, which pollinator would most likely exhibit similar feeding adaptations?

A species of hawk-moth distributed across Eurasia. (A) Signup and view all the answers

Which statement best explains how convergent evolution contributes to the observed similarities between cacti and euphorbia?

Both plant groups adapted to arid environments, leading to analogous structures. (A) Signup and view all the answers

Considering their respective geographic distributions, what primary factor might limit the range expansion of hummingbirds into regions where similar nectar-rich flowers are abundant?

Physiological constraints related to surviving colder climates. (C) Signup and view all the answers

If a species of euphorbia were introduced to a desert environment in the Americas, what evolutionary pressures might it face regarding competition with native cactus species?

Competition for water and other resources, potentially leading to character displacement. (C) Signup and view all the answers

How does biogeography support the theory of evolution considering the distributions of hummingbirds, hawk-moths, cacti, and euphorbia?

The varying traits of these organisms support species' responses to environmental conditions and historical isolation. (A) Signup and view all the answers

Which of the following best describes a transitional fossil?

A fossilized species exhibiting traits common to both an ancestral group and its descendants. (B) Signup and view all the answers

What is the significance of the Archaeopteryx fossil in the context of evolution?

It represents a transitional form, providing evidence of the evolutionary relationship between non-avian dinosaurs and birds. (B) Signup and view all the answers

What is the evolutionary significance of the furcula (wishbone) found in Archaeopteryx fossils?

It confirms the relationship between birds and dinosaurs, as the furcula is unique to these two groups. (A) Signup and view all the answers

Pakicetus is considered a transitional fossil that provides evidence for the evolution of which group of modern animals?

Modern cetaceans, including whales, porpoises, and dolphins. (B) Signup and view all the answers

How does the fossil record contribute to our understanding of evolution?

By offering a chronological sequence of life's history and demonstrating the changes in organisms over time. (A) Signup and view all the answers

Which of the following is NOT a category used to classify fossils based on their structure, composition, and/or role?

Replacement fossils, where organic material is directly substituted with other compounds. (B) Signup and view all the answers

A scientist discovers a new fossil with characteristics of both reptiles and mammals. How would this fossil contribute to the understanding of evolution?

It could provide further evidence for the evolutionary relationships between reptiles and mammals. (B) Signup and view all the answers

What is the most accurate definition of 'evolution' in a biological context?

The process by which species adapt over time in response to changes in their environment. (B) Signup and view all the answers

Adaptive radiation is best described as the:

Evolution of a group into diverse forms adapted to specialized ways of life. (D) Signup and view all the answers

Which of the following accurately describes homologous structures?

Structures that share a common ancestry but may have different functions. (C) Signup and view all the answers

The pentadactyl limb is an example of a homologous structure. What does the term 'pentadactyl' refer to?

A limb with five digits (fingers or toes). (B) Signup and view all the answers

What leads to similarities in analogous structures?

Identical environmental selection pressures. (C) Signup and view all the answers

Consider the wing of a bat and the wing of a butterfly. Which statement is most accurate?

They are analogous structures because they evolved independently to serve the same function. (D) Signup and view all the answers

Suppose scientists discover a new species of insect with mouthparts that closely resemble the feeding appendages of a crustacean. If these structures are determined to have arisen from different developmental pathways and genetic origins, what is the MOST likely relationship between them?

They are analogous structures, representing convergent evolution due to similar feeding strategies. (A) Signup and view all the answers

A population of birds colonizes a new island, and over time, different groups within the population evolve to specialize in feeding on different food sources (seeds, insects, nectar). This is an example of:

Adaptive radiation. (D) Signup and view all the answers

During vertebrate heart evolution, the transition from a two-chambered heart (fish) to a three-chambered heart (amphibians) and finally to a four-chambered heart (birds and mammals) represents modifications to improve the efficiency of oxygen delivery to tissues. How would you categorize these structural changes across different vertebrate groups?

Homologous structures demonstrating descent with modification from a common ancestor. (C) Signup and view all the answers

Which finding would provide the STRONGEST evidence that two seemingly different species evolved from a recent common ancestor?

Nearly identical DNA sequences for a particular gene. (B) Signup and view all the answers

A researcher is studying a newly discovered species of flightless bird. Based on the concept of vestigial structures, what would be the LEAST likely finding?

Completely absent wing structures with no skeletal remnants. (C) Signup and view all the answers

Which of the following provides the MOST direct evidence of evolutionary relationships between different species?

Molecular homogeny, such as shared DNA sequences. (B) Signup and view all the answers

A particular gene sequence is found to be highly conserved across many different species. What is the MOST likely explanation for this observation?

The gene performs a basic and essential function that is critical for survival. (C) Signup and view all the answers

A researcher is constructing a phylogenetic tree. Which type of characteristic is MOST useful for determining the evolutionary relationships among the species in the tree?

Homologous structures that are shared due to common ancestry. (A) Signup and view all the answers

Studying the similarities in the embryonic development of different vertebrate species provides evidence for:

A shared common ancestry among vertebrates. (C) Signup and view all the answers

Which of the following BEST describes the relationship between a whale pelvis and the human appendix?

Both are examples of vestigial structures. (C) Signup and view all the answers

If a gene in chickens and lampreys has 69% and 14% similarities to a human gene, respectively, what can be inferred?

Humans and chickens share a more recent common ancestor than humans and lampreys. (B) Signup and view all the answers

Which of the following pairs of organisms exhibit analogous structures primarily for efficient underwater locomotion?

Puffin (Class Aves) and Dolphin (Class Mammalia). (D) Signup and view all the answers

The presence of wisdom teeth in modern humans, which often require removal, is an example of a vestigial structure. What does this suggest about the evolutionary history of humans?

Ancestral human species likely had diets requiring more chewing and a larger jaw to accommodate extra molars. (A) Signup and view all the answers

Cacti and euphorbs, found in different plant families but occupying similar arid environments, both possess fleshy stems for water storage and spines for defense. This is an example of:

Analogous structures resulting from convergent evolution. (C) Signup and view all the answers

Which of the following accurately describes the evolutionary relationship indicated by vestigial structures?

Vestigial structures in two modern species indicate shared ancestry where the structure was functional. (A) Signup and view all the answers

A hummingbird and a hawk-moth both possess a long, straw-like proboscis used for extracting nectar from flowers. How does the concept of analogous structures apply here?

It demonstrates how similar environmental pressures can lead to the independent evolution of similar structures in distantly related organisms. (C) Signup and view all the answers

Consider the gliding 'wings' (patagium) of a sugar glider (marsupial mammal) and a flying squirrel (placental mammal). How do these structures exemplify analogous traits?

They are structurally different but serve a similar function, arising independently in separate evolutionary lineages. (A) Signup and view all the answers

A certain species of flightless bird has small, non-functional wings. What evolutionary information can be derived from this vestigial structure?

An ancestral species of the bird was capable of flight. (C) Signup and view all the answers

Which of the following pairs of structures is least likely to be considered analogous?

Leg of a human and leg of a fly. (D) Signup and view all the answers

Flashcards

Transitional Fossils

Fossils that show intermediate states between evolutionary forms, revealing transitions in species.

Pakicetus

An early whale relative with a unique inner ear structure, linked to modern whales through shared features.

Tiktaalik roseae

A four-legged semi-aquatic fish that signifies the transition from water to land in vertebrate evolution.

Pezosiren portelli

A transitional form between sea cows and manatees, with features for life both on land and in water.