Comprehensive Biology 1070: Origin, Evolution, and Extinction of Life

What is the estimated age of the Earth?

4.6 billion years ago (BYA)

What significant atmospheric components were present in early Earth?

Methane (CH4), ammonia (NH3), water, and hydrogen (H2)

What was the significance of the absence of oxygen in early Earth?

It was crucial for the initial formation of biomolecules.

What did the first prebiotic simulation experiment by Miller and Urey produce?

Amino acids.

What are liposomes?

Membrane structures formed by phospholipids under certain conditions.

What are progenotes?

The first membrane-bound aggregations of RNA, DNA, proteins, and lipids.

What major event did the origin of photosynthesis bring about?

The introduction of molecular oxygen into the atmosphere.

What evidence indicates early oxygenation of the atmosphere?

Iron deposits dating back 2 billion years ago (BYA).

What is the endosymbiont theory?

It posits that mitochondria and chloroplasts originated as free-living bacteria that were engulfed by other bacteria.

What similarities exist between mitochondria, chloroplasts, and free-living bacteria?

They replicate similarly, have their own DNA, RNA, and ribosomes, and are bound by two membranes.

How is mitochondrial DNA typically inherited?

It is generally inherited from the maternal line.

What are some characteristics of the first eukaryotic cells?

They arose about 1.9-1.4 billion years ago and are characterized by complex organelles.

What is one possible origin of multicellularity?

It may have originated as a cooperative effort where multiple cells came together or daughter cells failed to separate.

What allows for the development of diverse body plans in multicellular organisms?

Specialization of particular cell populations.

What period preceded the Cambrian Period and featured strange organisms?

The Ediacaran period (635-543 million years ago).

What major biological events occurred during the Paleozoic Era?

It encompasses major periods of biological diversification.

What significant evolutionary event occurred between 543-490 million years ago?

All major animal phyla evolved.

What is the significance of the Burgess Shale?

It preserved many of the organisms from the Cambrian explosion.

When did the first jawless vertebrates appear?

During the Ordovician Period, about 490-430 million years ago.

What is the geological timescale defined by?

Major geologic and biological events.

What is the significance of ozone in the early atmosphere?

It helps block harmful UV rays that can damage DNA and other macromolecules.

What are some examples of endosymbiosis?

Organelles with more than two membranes and remnants of engulfed cell nuclei.

What significant event marks the end of the Ordovician period?

A massive extinction.

What was the supercontinent that drifted south during the Paleozoic Era?

Gondwana.

During which period did the first vascular plants appear?

The Silurian Period (about 443-417 MYA).

What major evolutionary development occurred during the Devonian period?

The first amphibians appeared.

What is the time frame of the Carboniferous Period?

354-290 MYA.

What significant evolutionary advancement occurred in reptiles during the Permian Period?

The evolution of the amniotic egg.

What was the most severe extinction event in Earth's history?

The Permian-Triassic Extinction.

What percentage of marine and terrestrial species went extinct during the Permian-Triassic Extinction?

More than 90% of marine species and 70% of terrestrial species.

What characterizes the Mesozoic Era?

It is known as the age of reptiles.

Which period is known for the dominance of archosaur reptiles?

The Triassic Period (248-206 MYA).

What major event occurred at the end of the Cretaceous Period?

A mass extinction event caused by an asteroid impact near the Yucatan Peninsula.

What is the current era known as, starting from 65 MYA?

The Cenozoic Era, known as the age of mammals.

What do fossils provide evidence for in the context of evolution?

They provide the earliest evidence for evolution, show that species have gone extinct, and demonstrate that the planet has changed over time.

What is the definition of a fossil?

Any evidence of an organism that is older than 10,000 years.

What are the conditions necessary for fossil formation?

Rapid burial, anoxic conditions (low oxygen), or very dry conditions.

What type of fossil forms when fine sediment compresses a specimen?

Compression fossils.

How do petrification fossils form?

When an organism is buried and dissolved minerals replace bone or other organic material.

What do impression fossils provide insight into?

Animal behavior, as they can form trace fossils.

What are cast fossils?

Fossils that form when impressions are filled with mud, providing a mold.

What are intact preservation fossils?

Fossils that occur when tree resin traps an organism and hardens, preserving amazing detail.

Why is the fossil record often incomplete?

Fossilization is rare, and erosion and continental shifts likely destroy many fossils.

What is one method used to determine the age of fossils?

Radiometric dating and stratigraphy are common methods.

What is relative dating in geology?

A method that relies on stratigraphy, or evidence surrounding a specimen, to determine its age.

What does stratigraphy study?

The study of rock layers (strata) and their chronological relations and composition.

What is absolute dating?

A method that utilizes the actual fossil or specimen itself to determine its age.

What is radiometric dating?

A form of absolute dating that uses radioactive isotopes as clocks to determine the age of fossils.

What is an isotope?

An atom with a different number of neutrons compared to other atoms of the same element.

How does radiometric dating work?

It measures the changing proportions of isotopes as they decay over time.

What is half-life in the context of radiometric dating?

The amount of time it takes for half the isotopes in a sample to decay into the parent atom.

What is the half-life of Carbon-14 and what can it date?

5730 years; it can be used to age objects up to about 40,000 years old.

What is the half-life of Potassium-40 and what can it date?

1.3 billion years; it can be used for dating fossils that are 300,000 years or older.

What does biogeography study?

The distribution of species across the planet.

What factors impact species distribution?

Climate, geography, and evolutionary/geologic history.

How does plate tectonics explain species distribution?

It posits that the Earth's crust is made of moveable plates, affecting how species are distributed.

What significant event occurred around 110 million years ago regarding marsupials?

Marsupials receded due to the rise of placental mammals.

What is the Wallace line?

A boundary that describes a shift from more Australian-like fauna to more Asian-like fauna in Southeast Asia.

Who is considered the father of modern biogeography?

Alfred Russel Wallace.

What are homologous structures?

Structures that share common ancestry, which may not necessarily have the same function.

What are vestigial structures?

Structures that have no apparent function but may indicate shared ancestry.

What are analogous structures?

Structures that share similar functions but have different ancestral origins.

How do analogous structures arise?

They arise as similar solutions to similar problems in different evolutionary lineages.

Why is assessing homology important in evolutionary biology?

It helps to understand evolutionary relationships and shared ancestry.

What can obscure evolutionary relationships when assessing structures?

Inferring analogous structures as homologous can obscure true evolutionary relationships.

What is the subdiscipline of Island Biogeography?

It examines the distribution of organisms on islands, relating to similar questions in biogeography.

What does evolutionary developmental biology (evo-devo) study?

It examines developmental pathways and their relationships.

What insights can be gained from mistakes in development?

They help us understand how particular body plans arise by looking at specific genes.

What are homeotic genes?

Genes that, when mutated, can lead to abnormal or misplaced structures.

What is a genome?

The complete set of genes or genetic material of an organism.

What are Ultra-conserved Elements (UCEs)?

Highly conserved regions of DNA found across all vertebrates, whose functions are not fully understood.

How do UCEs help in understanding evolutionary relationships?

They quantify differences in adjacent (flanking) regions of DNA sequences; the more similar the sequences, the more closely related the species.

What is evolution?

The change in heritable characteristics over time, often summarized as 'descent with modification'.

What evidence do fossils provide regarding evolution?

They show that organisms have gone extinct, contradicting static creation narratives.

Who was one of the first to suggest common ancestry among groups?

Georges-Louis Buffon in 1749.

What is the theory of uniformitarianism?

Proposed by James Hutton, it suggests that the slow processes acting today also occurred in the past.

What principle did Georges Cuvier develop?

The principle of superposition, stating that lower rock layers are older than those above them.

How did Charles Lyell contribute to the understanding of Earth's age?

He argued that the Earth was hundreds of millions of years old, not just 6,000 years.

What mechanism did Jean Baptiste Lamarck propose for evolution?

He suggested that organisms acquired traits over their lifetime and passed them on to successive generations.

What did Darwin observe during his voyage on the HMS Beagle?

He noted a strange distribution of fossils and a variety of species in similar habitats, indicating convergent evolution.

What phrase did Darwin coin to describe the process of evolution?

Descent with modification.

What critical insight did Thomas Malthus provide to Darwin?

He stated that resources are finite, leading to competition where not all organisms survive to reproduce.

What is variation in the context of Darwin's theory?

Variation is a key assumption; some variations are more advantageous than others.

What is natural selection according to Darwin?

The preservation of favorable traits over inferior ones.

What was the mission of the HMS Beagle?

To take detailed hydrographic measurements.

What did Darwin theorize about the finches on the Galapagos Islands?

He theorized that they descended from a single common ancestor.

What is the significance of the phrase 'descent with modification'?

It encapsulates Darwin's theory that species evolve over time from common ancestors.

What did Darwin reason about the survival of organisms?

Better equipped organisms would survive over poorly equipped ones.

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

Artificial selection is when humans act as agents of selection, choosing specific traits in organisms, unlike natural selection where environmental factors drive the selection process.

What is an example of natural selection observed in finches?

The foraging behavior of finches is influenced by their beak size and shape, allowing those with advantageous variations to exploit different food resources.

What are the four postulates of natural selection?

1. Organisms vary. 2. Some variations are heritable. 3. Not all organisms survive to reproduce. 4. Survival is, at least in part, nonrandom.

What significant work did Charles Darwin publish in 1859?

Darwin published 'On the Origin of Species', which presented his theory of evolution through natural selection.

What issue did Darwin's theory face regarding inheritance?

The issue of blending inheritance, which suggested that offspring were an even mix of parental characteristics, would dilute favorable variations.

How did Gregor Mendel contribute to the understanding of inheritance?

Mendel's experiments with pea plants demonstrated a mechanism of inheritance that validated Darwin's theory.

What is the modern evolutionary synthesis?

The modern evolutionary synthesis unifies Mendel's and Darwin's ideas, adding that mutations are responsible for observed variations.

What is a mutation in the context of evolution?

A mutation is a change in the nucleotide sequence that can introduce new alleles into a population.

What is a gene pool?

The entire collection of genes and their alleles in a population.

What is the difference between genotype and phenotype?

Genotype refers to an organism's genetic makeup, while phenotype is the physical manifestation of that genetic makeup.

What is an adaptation?

An adaptation is a variation that helps an organism survive and reproduce.

What does 'survival of the fittest' mean in evolutionary terms?

In evolutionary terms, fitness refers to an organism's genetic contribution to the next generation, not merely survival.