Biological and Geological Changes in the History of Life on Earth

These flashcards cover key concepts from the lecture on the history of life on Earth, including evolutionary theory, geological time scale, and mechanisms of evolution.

What are the first organisms believed to have evolved on Earth?

Prokaryotes that evolved in the ocean and performed anaerobic respiration.

What significant process did cyanobacteria perform?

Cyanobacteria produced oxygen through photosynthesis.

What major revolution allowed aerobic respiration to occur?

Oxygen Revolution.

What type of organisms evolved after the first prokaryotes?

Autotrophs.

How long ago did the first organisms appear?

3.5 billion years ago.

What does the geological time scale help illustrate?

The major divisions of Earth's history including eras and periods.

What is the Precambrian Era known for?

Primitive marine life existing from 4.6 BYA to 570 MYA.

What is the significance of mass extinctions?

They result in the loss of 40% or more of life and can occur due to various factors like climate change.

What human impacts are included in the Anthropocene?

Habitat destruction, invasive species, overpopulation, pollution, overharvesting, and climate change.

What hypothesis suggests that life originated from non-living matter?

Abiogenesis.

What experiment supported the origin of organic molecules?

The Miller-Urey Experiment in 1952.

What do Iron-Sulfide Bubbles Hypothesis and Lipid Membrane Hypothesis propose about early life?

They propose theories about how early life forms could have emerged from specific environmental conditions.

What does the RNA World Hypothesis indicate?

That RNA was the first genetic material, capable of self-replication.

What is the process by which organisms better adapted to their environment tend to survive?

Natural Selection.

What does the Hardy-Weinberg Equilibrium illustrate?

The genetic variation in a population will remain constant in the absence of disturbing factors.

What is required for the Hardy-Weinberg Equilibrium to exist?

No mutations, random mating, no natural selection, large population, no gene flow.

What can adaptations be classified into?

Structural, physiological, and behavioral adaptations.

What are vestigial organs?

Structures that have no function in the living organism, such as the human appendix.

What do analogous structures indicate?

They have similar functions but do not share a common ancestry.

Name a major type of natural selection that favors the average trait.

Stabilizing Selection.

What is an example of directional selection?

Thicker-shelled oysters surviving better than thinner-shelled oysters.

What is diversifying selection?

Selection that favors both extreme traits over average traits.

What is the process of biogeography?

The study of the geographic distribution of organisms.

What do transitional fossils represent?

Fossils that show intermediate states between ancestral traits and their descendants.

What is the Bottleneck Effect?

A reduction in population size affecting gene frequencies in surviving members.

What is the Founder Effect?

When isolated individuals set up a new population with different gene frequencies than the parent population.

What role do mutations play in evolution?

They create new alleles and genetic variations within a population.

What do comparative embryology and biochemistry studies reveal?

Similarities in developing organisms and at the biochemical level among different species.

What is the significance of Darwin's observations on his voyage?

They led to his formulation of the theory of natural selection.

What are the three types of barriers to speciation?

Pre-zygotic barriers, mating attempts, and post-zygotic barriers.

What is allopatric speciation?

Speciation that occurs due to geographic isolation.

What is sympatric speciation?

Speciation occurring within the same geographic area, often due to sexual selection.

What does the term macroevolution refer to?

Major evolutionary changes over long periods of time.

What does microevolution describe?

Minor evolutionary changes within a species over short periods.

What is coevolution?

When two or more species reciprocally affect each other's evolution.

How does the environment impact evolution?

It can shape adaptations and evolutionary pressures on populations.

What process can lead to the modification of existing structures over generations?

Adaptation.

How do human DNA similarities to other species support evolutionary theory?

It shows common ancestry and genetic relatedness.

What are examples of structural adaptations in animals?

Woodpecker's beak and anteater's snout.

What mechanism is described as the accumulation of knowledge across generations?

Cultural Evolution.

Name one way artificial selection can have unintended consequences.

It can lead to issues like narcolepsy in dogs.

What are pre-zygotic barriers?

Barriers preventing mating or fertilization between species.

What is an example of a historical context for evolutionary theory?

Lamarck's idea of inheritance of acquired characteristics.

What is the function of the appendix in humans?

It is a vestigial organ with no essential function.

What does the term genetic drift refer to?

Rapid changes in gene frequency in a small population due to random events.

What is the difference between behavioral adaptations and physiological adaptations?

Behavioral adaptations involve responses to the environment, while physiological adaptations are chemical changes for function.

Why is the study of fossils important in evolution?

Fossils provide evidence of past organisms and their evolutionary history.

How do hybrid organisms like mules relate to the definition of a species?

They do not meet the criteria because they are sterile and cannot produce fertile offspring.

What does the term adaptive radiation refer to?

Divergent evolution where a species adapts to various roles in different habitats.

What effect do increased mutations generally have on populations?

They create genetic diversity, which can lead to adaptation.

What is one common misconception about natural selection?

That it grants organisms what they 'need', rather than selecting variations that already exist.

Name a behavior that can be classified as a behavioral adaptation in animals.

Birds migrating to avoid harsh winters.

What phenomenon can result from climate change, impacting survival rates of species?

Mass extinction.

What is the significance of the Cretaceous Period?

It marked the end of the dinosaurs about 65 million years ago.

How is the concept of equilibrium relevant to Hardy-Weinberg principles?

It predicts that genotype and allele frequencies will remain constant in a population at equilibrium.

What major factors can disrupt Hardy-Weinberg equilibrium?

Mutations, non-random mating, natural selection, genetic drift, and gene flow.

Explain the term 'punctuated equilibrium'.

An evolutionary theory that proposes rapid changes followed by long periods of stability.

What type of selection favors both extremes of a trait?

Diversifying selection.

Define artificial selection in the context of evolution.

Humans breed plants and animals for desired traits.

What is a defining feature of convergent evolution?

Species from different lineages evolve similar traits due to similar environmental pressures.

What role do catastrophes play in G. Cuvier's theory of catastrophism?

Catastrophes lead to mass extinctions and shape the Earth's history.

What type of anatomical evidence did Darwin observe that supported his theory?

Homologous structures indicating common ancestry.

Explain the term 'struggle for existence' as used by Darwin.

The competition among organisms for resources that affects survival and reproduction.

What is the relationship between natural selection and genetic variation?

Natural selection acts upon the variations within a population to influence evolutionary changes.

What is the significance of the sedimentary rock layers in studying fossils?

They offer chronological information about when different organisms existed.

Describe the 'law of superposition'.

In undisturbed sedimentary rocks, older layers are found deeper than younger layers.

What hypothesis indicates that life might exist throughout the universe?

Panspermia.

What is the evidence for evolution from comparative biochemistry?

Similar biochemical processes and molecules across different species.

How do organisms' adaptive traits change over time?

Through natural selection where favorable traits become more common in the population.

What is an ecological equivalent?

Different species that occupy similar ecological roles in different environments.

What mechanism leads to the formation of new alleles?

Mutations.

How can sexual selection impact evolution?

It can drive the development of traits that improve mating success.

What evidence did the Murchison meteorite provide for the origin of life?

It contained amino acids, suggesting organic molecules may exist in space.

What evolutionary concept did Wallace independently develop?

Natural Selection.

What are homologies in comparative anatomy?

Similarities in an organism’s structure due to shared ancestry.

How does speciation occur?

Through geographic and reproductive isolation leading to divergence among populations.

What is one way to measure evolutionary change in a population?

By tracking changes in allele frequency over generations.

What is the role of gene flow in populations?

It introduces new alleles into a population, impacting genetic diversity.

What does the term 'bottleneck' refer to in evolutionary biology?

A significant reduction in population size leading to decreased genetic diversity.