L17: Evolution and Biodiversity

Question 1

What experiment in the 1950s provided insight into the origin of life on Earth?

Answer 1

Stanley Miller’s experiment, which used hydrogen, ammonia, methane, and heat in an anaerobic environment to create organic molecules, including amino acids

Question 2

What is the Cambrian Explosion, and why is it significant?

Answer 2

The Cambrian Explosion, around 500 million years ago, marked a rapid diversification of life, including the evolution of plants and animals onto land

Question 3

How did the asteroid impact during the Cretaceous period affect life on Earth?

Answer 3

It caused massive extinction (including dinosaurs) by creating dust that blocked sunlight, leading to acid rain and fires, which transformed ecosystems and enabled mammals to thrive

Question 4

What theory explains the origin of Homo sapiens in Africa?

Answer 4

The “Out of Africa” or “Single Origin Hypothesis,” which suggests that modern humans evolved in Africa and migrated to replace other hominin species

Question 5

What are some adaptations seen in Homo sapiens that differentiate them from other species?

Answer 5

Bipedalism, larger brain size, extended gestation, and a longer period of infancy dependency

Question 6

Define “natural selection” according to Darwin’s theory

Answer 6

Natural selection is the process where individuals with traits best suited for survival in an environment reproduce more, passing advantageous traits to offspring

Question 7

What is biogeography and how does it support evolution?

Answer 7

Biogeography is the study of the distribution of species across geographical areas, showing evidence of evolution through isolation, such as marsupials in Australia

Question 8

What are vestigial structures, and why are they considered evidence of evolution?

Answer 8

• Structures that served a function in ancestors but are now redundant, like the human appendix, indicating evolutionary heritage and adaptation from ancestral forms

Question 9

Name a model organism and its significance in research

Answer 9

Zebrafish, used for cardiovascular research due to its transparent embryos and ability to regenerate heart tissue

Question 10

What is the Anthropocene extinction event?

Answer 10

The current mass extinction driven by human activities such as habitat destruction, pollution, and climate change

Question 11

What role does biodiversity play in medicine?

Answer 11

Many medicines are derived from plants and animals, highlighting the importance of biodiversity for discovering new drugs and treatments

Question 12

How can studying evolutionary relationships improve medical research?

Answer 12

Understanding homology helps in modeling diseases, studying drug responses, and developing treatments based on shared genetic traits

Question 13

What is RNA’s role in early life formation according to the Miller-Urey experiment findings?

Answer 13

RNA is thought to be one of the first organic molecules formed, which could self-replicate and organize into primitive life forms

Question 14

How does geographic isolation lead to speciation?

Answer 14

• Geographic barriers prevent interbreeding, leading to separate evolutionary paths that eventually result in distinct species adapted to their specific environments
• Isolation prevents gene flow, leading populations to evolve separately and form new species

Question 15

What does the Linnaean taxonomy classify?

Answer 15

• It organises all known species into hierarchical categories: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species
• Bases on physical and genetic characteristics

Question 16

Why did Darwin’s observations on the Galapagos Islands support his theory of natural selection?

Answer 16

• He observed differences in traits like finch beak shapes and tortoise shells, adapted to different environmental needs on each island
• Suggested natural selection and speciation

Question 17

What are transitional fossils and why are they significant?

Answer 17

Transitional fossils show intermediary forms between species, like Archaeopteryx between dinosaurs and birds, providing evidence of evolutionary change over time

Question 18

How does genetic variation drive evolution?

Answer 18

Genetic mutations and recombination during reproduction create variations; advantageous traits increase survival and reproduction rates, spreading through populations

Question 19

What are homologous structures and how do they support the theory of evolution?

Answer 19

Homologous structures, such as vertebrate limb bones, are similar across species due to shared ancestry, supporting common descent

Question 20

Explain the importance of studying model organisms in biomedical research

Answer 20

• Model organisms are non-human species, like mice and fruit flies, and help scientist study biological processes
• Share genetic and biological characteristics with humans, enabling insights into genetics, disease, and treatments

Question 21

What evolutionary evidence do retroviral insertions in genomes provide?

Answer 21

They show shared ancestry, as organisms with common ancestors retain similar retroviral DNA insertions from past infections

Question 22

What is microevolution? How does antibiotic resistance demonstrate this?

Answer 22

• Small evolutionary changes within a species
• Bacteria evolve resistance to antibiotics due to selection pressures, showing adaptation and evolution within a short timescale

Question 23

How do antibiotics select for resistant bacteria?

Answer 23

Non-resistant bacteria do not survive, antibiotics create a survival advantage for bacteria with resistance traits, allowing them to reproduce

Question 24

What is metabolic syndrome, and how is it related to human evolution?

Answer 24

Metabolic syndrome involves conditions like obesity and diabetes, arising from a mismatch between our ancestral genes and modern lifestyles

Question 25

What is Darwin’s tubercle, and what does it indicate?

Answer 25

Darwin’s tubercle is a small bump on the ear, considered a vestigial structure from our evolutionary ancestors, showing remnants of evolutionary traits

Question 26

Why is biodiversity crucial for food security?

Answer 26

Biodiversity provides a range of nutrients and food sources, increasing resilience against diseases and environmental changes affecting agriculture

Question 27

How has human activity contributed to climate change, impacting biodiversity?

Answer 27

Industrialisation and intensive farming increase greenhouse gases, driving climate change and threatening species through habitat destruction and extreme weather

Question 28

Why are regulatory bodies important in the use of model organisms in research?

Answer 28

They enforce ethical standards like the 3 Rs (Replacement, Reduction, Refinement) to minimize harm and ensure responsible use of animals in science

Question 29

What evolutionary role did cyanobacteria play in Earth’s history?

Answer 29

Cyanobacteria were among the first organisms to perform photosynthesis, producing oxygen and altering Earth’s atmosphere

Question 30

What caused the Permian extinction event, and what was its significance?

Answer 30

Possibly triggered by volcanic activity or a meteor, it led to massive species loss, creating new ecological niches for early dinosaurs

Question 31

What does phylogenetic tree analysis help us understand?

Answer 31

It maps evolutionary relationships, showing how closely or distantly species are related based on common ancestors

Question 32

Define “survival of the fittest” in evolutionary terms

Answer 32

It describes how organisms best adapted to their environments are more likely to survive and pass on advantageous traits

Question 33

What role do mitochondria play in evolutionary theory?

Answer 33

Mitochondria are thought to have originated from symbiotic bacteria, supporting the endosymbiotic theory in the evolution of eukaryotes

Question 34

What is genetic drift, and how does it affect evolution?

Answer 34

Genetic drift is a random process that causes gene frequencies to change over time, impacting small populations especially

Question 35

What is artificial selection, and how does it differ from natural selection?

Answer 35

Artificial selection is when humans breed organisms for desired traits, as opposed to natural selection driven by environmental pressures

Question 36

What evidence supports evolution through embryology?

Answer 36

Early developmental stages of embryos in different species show similarities, indicating a common evolutionary origin

Question 37

What are transitional fossils, and why are they important?

Answer 37

Fossils that display characteristics of two distinct groups, bridging evolutionary gaps, like Archaeopteryx between dinosaurs and birds

Question 38

What is the significance of gene homology in evolution?

Answer 38

High genetic similarity between species, like humans and chimpanzees, shows shared ancestry and supports evolutionary theory

Question 39

Describe the significance of E. coli in scientific research

Answer 39

E. coli is a widely used model organism in molecular biology for studying gene function and protein expression

Question 40

Why is biodiversity important for ecosystem stability?

Answer 40

Diverse species provide resilience against environmental changes, pests, and diseases, supporting ecosystem health

Question 41

What is the purpose of the Red List maintained by the IUCN?

Answer 41

It tracks species at risk of extinction, raising awareness of biodiversity loss and conservation needs

Question 42

What is the Holocene extinction event, and what are its causes?

Answer 42

The current mass extinction driven by human activities, including habitat destruction, climate change, and pollution

Question 43

Why are amphibians like Xenopus used in embryology studies?

Answer 43

Their large, easily manipulated embryos make them ideal for studying early development and toxicology