Topic 01 - Biol 213

Practice flashcards covering the origins of life, the history of evolutionary thought, and the characteristics of worldviews as presented in the Topic 01 lecture.

Abiogenesis

The creation of organic molecules, such as amino acids and nitrogenous bases, from abiotic materials.

Recipe for life on Earth

1, creation of organic molecules 2. molecules join to form organic macromolecules 3. formation of protocells 4, molecules begin self replicating to allow inheritance

Protocells

Membrane-bound droplets, like liposomes, that maintain an internal chemistry separated from the external environment.

Miller-Urey Experiment (1953)

proved abiogenesis by showing that a spontaneous reaction under early-Earth conditions can produce amino acids and organic molecules from inorganic materials.

Panspermia

The hypothesis that life evolved elsewhere in the universe and was brought on Earth by meteorites

Murchison Meteorite Evidence

A 4.56 billion-year-old rock that landed in Australia (1969) and tested positive for lipids, over 90 amino acids, and nitrogenous bases like uracil and xanthine

RNA world hypothesis

The theory that the first information-containing molecule was RNA, not DNA, and that it was capable of catalyzing reactions.

Ribozymes

RNA molecules that are capable of catalyzing chemical reactions.

LUCA

Last Universal Common Ancestor

Earliest Evidence of Life

Occurred 3.5–4.1 billion years ago, began in the oceans, and the early organisms were anaerobic prokaryotes.

Great Oxidation Event

An event occurring between $2.4-2.1\,Ga$ where the evolution of photosynthesizing organisms led to an aerobic atmosphere.

Cambrian Explosion

The abrupt appearance of most major animal lineages in the fossil record between $541$ and $\sim 520\,Ma$ ago.

The "Big Five" Mass Extinctions

Extreme natural extinction events where massive percentages of families died out, creating massive opportunities for surviving lineages to flourish.

Evolution

A change in the frequency of alleles in a population over time.

Phenotypic Evolution

A change in the distribution of phenotypic traits within a population over time.

Allele

A unique copy of a gene.

Population

A group of interbreeding individuals.

Phenotypic trait

Any characteristic of an organism that is an expression of a gene, such as eye color, height, or physiological response.

Selection acts on ________, but evolution acts on ________.

individuals population

Theory of Special Creation (17th Century Europe Viewpoint)

A literal interpretation of Genesis stating that Earth and its species were created recently, species were created independently, and species do not change through time.

Georges Cuvier (1769–1832)

Naturalist and founding father of paleontology who studied fossil layers and discovered that species go extinct while others survive.

Uniformitarianism (Hutton & Lyell)

The geological principle that processes shaping the Earth in the past are the same as those that shape it currently.

Transmutation

Jean-Baptise Lamarck's theory that acquired traits can be inherited through use and lost through disuse.

Thomas Malthus (1766–1834)

Noted that populations grow geometrically while food supplies grow arithmetically, meaning population increases inevitably lead to a fierce competition for survival.

The Origin of Species (1859)

Descent with modification and Natural Selection.

Natural selection

The principle by which slight variations of a trait are preserved if they are useful for survival or reproduction.

Descent with modification

The evolutionary concept that historically all organisms arise and diversify from a single common ancestor.

Three Conditions for Natural Selection

1. Variation: Phenotypic differences exist in a trait within a population. 2. Heritability: Variation must be genetic and transmissible to offspring. 3. Differential Fitness: Variation must lead to differences in survival or reproductive success.

Fitness

The differential reproductive and survival success of an individual, allowing them to pass on more alleles to the next generation.

Indirect vs. Direct Evidence of Evolution

Indirect Evidence: Paleontology, homology (molecular, morphological, and developmental). Direct Evidence: Artificial selection, real-time lab/field observations of evolution.

Paleontology

The study of ancient organisms preserved in the fossil record showing that life is ancient, organisms go extinct, and transitional species link past and present forms

Homology

A trait inherited from a common ancestor that develops into a variety of forms and functions.

Morphological & Developmental Homology

Shared anatomical structures layout among mammals (e.g., shared mammalian limb bones) and early embryonic structures

Molecular Homology

The shared genetic language of all life; highlights that all living organisms use the exact same central dogma DNA RNA Protein and triplet codon maps.

Artificial Selection

Direct human-driven selection of specific traits over generations

Direct Observations of Evolution

real-time laboratory and field tracking experiments showcasing evolutionary changes over generations in fast-reproducing organisms

Worldview

A fundamental framework of beliefs, values, and assumptions through which reality is perceived and interpreted.

Knowledge system

A structured and shared way of producing and transmitting knowledge.

When Great Oxidation Event

~2.4 Ga (billion years ago).

First Eukaryotic Cells apperance

~2.0 Ga (billion years ago)

First Multicellular Algae Timeline

~1.2 Ga (billion years ago).

First Animals Timeline

~800–600 Ma (million years ago)

when Cambrian Explosion

541 Ma (million years ago).

First Land Plants

~470–450 Ma (million years ago). They were likely the first multicellular organisms to establish themselves on land.

First Land Arthropods

~430 Ma (million years ago). They were the first animals to proliferate on land, utilizing the food and shelter created by plants.

First Land Vertebrates

~370 Ma (million years ago). They represent the first land-dwelling vertebrates.

Evolution of the Amniotic Egg

~320 Ma (million years ago). It allowed vertebrates to live their entire life cycle on land without needing water to reproduce.

rise of complex life Timeline

1. Great Oxidation Event 2. First eukaryotic cells 3. First multicellular algae 4. First animals 5. Cambrian Explosion

colonization of land timeline

1. Land plants arrive 2. Arthropods transition to land 3. Lobe-finned fishes move onto land 4. Evolution of the amniotic egg

Why do mass extinctions often lead to rapid diversification of surviving lineages?

Previously unoccupied niches become available.

Which of the following statements is true of the Cambrian explosion?

Many lineages of animals first appear in the fossil record in a short window of time.

True or False: Natural selection acts on individuals, but evolution is a population process.

True.

True or False: Natural selection is a random process.

False

Which of the following provides the strongest evidence that birds evolved from theropod dinosaurs?

Fossils of feathered dinosaurs possessing fused clavicles

A student creates microscopic lipid droplets that spontaneously form phospholipid bilayers. These droplets can grow and occasionally divide, but contain no genetic material. What structures from early life on Earth do these droplets most resemble?

Protocells.

Which of the following counts as a direct piece of evidence for evolution?

Observation of changes in the distribution of traits in crops over time due to selective breeding

A bonobo, Georgina, controls access to a grove of mango trees which produce many mangoes annually. Other bonobos don't have access to as many mangoes as she does. So, she is more likely to attract mates, reproduce, and pass on more alleles to the next generation. Is natural selection acting here in the case of Georgina's mango wealth? Why, or why not?

It is only natural selection if her mango wealth is caused by an inherited trait. Georgina has a clear advantage in surviving and reproducing , but this only counts as natural selection if a heritable trait like strength or intelligence is what allows her to control the grove. If it is just due to chance or location rather than a genetic trait passed down to her offspring, then it is not natural selection.