Evolution

Scientific hypothesis

A testable, clear statement about what you think will happen based on prior knowledge.

Scientific Theory

A logical explanation for how or why something occurs in the natural world, supported by extensive evidence.

Scientific Law

Predicts the results of certain initial conditions.

Early Earth

Formed approximately 4.6 billion years ago.

What was the surface of early Earth like?

Very hot (300 F), molten magma oceans, no O2 atmosphere, intense radiation, collision created the moon, volcanoes.

When did life evolve on Earth?

Life evolved approximately 3.5 billion years ago.

Where did life first appear on Earth?

At deep sea hydrothermal vents due to chemical energy, nutrients, and protection from harsh surface conditions.

What kingdom did the first life forms resemble?

Archaebacteria, kingdom Monera.

Urey-Miller Apparatus

An experimental setup that simulated early Earth conditions to produce amino acids, suggesting life could originate from non-living matter.

Why was the Urey-Miller experiment important?

It provided experimental evidence that life could originate from non-living matter by producing amino acids.

What was found 55 years later in the Urey-Miller experiment?

Over 20 different amino acids were found, strengthening the original conclusion and indicating greater diversity.

How could the Urey-Miller hypothesis be tested today?

By simulating diverse early Earth environments with updated atmospheric models and testing for RNA formation.

Panspermia Theory

The theory that life on Earth may have originated elsewhere in the universe and was brought here through space.

Does the Panspermia Theory explain the origin of life?

No, it proposes a mechanism for distribution, not the actual origin of life.

How could Panspermia Theory be tested?

Through experimental simulations of space travel and searching for evidence of extraterrestrial life.

Primordial Soup Theory

Life originated from inorganic molecules that combined to form organic molecules leading to the first cell.

Miller-Urey Experiment

Demonstrated how simple organic molecules could be formed from inorganic compounds under early Earth conditions.

RNA World Hypothesis

Suggests RNA was the primary genetic material in early life forms, able to carry genetic information and act as an enzyme.

First prokaryotic life forms appearance

A little after 4000 million years ago.

Prokaryotes with internal membranes

Appeared a little before 3000 million years ago.

Abundant oxygen in the atmosphere

Occurred between 3000 million years and 2000 million years ago.

Endosymbiotic life with mitochondria

Occurred a little before 1000 million years ago.

Endosymbiotic life with chloroplasts

Occurred at 1000 million years ago.

First multicellular life forms appear

A little after 1000 million years ago.

Shelled invertebrates

Appeared a little after 600 million years ago.

First vertebrates, jawless fish

Appeared a little after 500 million years ago.

Plants and arthropods invade land

Occurred a little before 400 million years ago.

Amphibians and trees appear on land

Occurred a little after 400 million years ago.

Reptiles appear

Occurred a little before 300 million years ago.

Early dinosaurs appearance

Occurred a little before 200 million years ago.

Early mammals appearance

Occurred a little after 200 million years ago.

First birds appearance

Occurred a little after that (200 million years ago).

Dinosaurs disappear

Occurred a little after 100 million years ago.

First primates appearance

Occurred right before 0.0.

Pre-1700s European beliefs

The Bible was taken as fact; no concept of evolution.

Baron George Cavier's theories

Earth was 6000 years old and unchanged; proposed Catastrophism.

Hutton and Lyell's contribution

Theorized Earth is very old and geological changes occur slowly over time.

George Buffon's theory

Species change over time lead to new organisms.

Carl Linnaeus's theory

New species arise from hybridization and interbreeding.

Erasmus Darwin's theory

All life developed from a single source; humans may relate to primates.

Jean-Baptiste Lamarck's theory

Species adapt to changing environments and inherit acquired traits.

Charles Darwin's voyage

5-year voyage on the HMS Beagle to collect samples and observe nature.

Darwin's observations

Noted similarities between living and extinct species; inferences about homologous features.

Galapagos Islands observations

Different beaks of mockingbirds and finches based on island habitats.

Wallace's observations

Noted similarities in creatures on nearby islands despite different habitats.

Natural Selection

The process which shapes species based on traits that affect reproductive success.

Darwin's theory publication

Published in 1859 titled 'On the Origin of Species by Means of Natural Selection'.

Variations in species

Physical characteristics vary, and these variations can be passed on.

Struggle for Existence

Species compete for limited resources, with some better adapted to capture those resources.

Survival of the Fittest

Certain members are selected to produce more offspring due to advantageous traits.

Adaptation process

Natural selection causes evolution towards better adaptation to the environment.

Darwin's assumptions

Offspring vary, some variation is inheritable, and populations remain stable.

Inferences leading to Natural Selection

Survivors pass on favourable traits over time, affecting the population's genetic makeup.

Homologous structures

Similar structures with different functions, indicating common ancestry.

Analogous structures

Different structures with similar functions due to similar environmental pressures.

Vestigial structures

Functionless organs in current species that had functions in ancestors.

Macroevolution

Large scale evolutionary changes leading to the classification of distinct groups.

Microevolution

Small changes in allele frequencies within populations or species.

Fossil Record

Evidence of variety, extinct, and transitional species.

Fossils

Preserved remains or traces of organisms from the past.

How fossilization occurs

Lithification involving compression and turning sediments into stone.

Types of fossils

Include encrustation, tar impregnation, amber entombment, refrigeration, mummification, casts, tracks.

How fossil ages are determined

Through radiometric dating of isotopes.

Chemical and Anatomical Similarities

Common cellular structure, proteins, carbohydrates, lipids, and nucleic acids across living organisms.

Geographical Distribution of Species

Isolated areas evolve distinct species due to limited interaction with other populations.

Genetic changes over generations

Quickly maturing organisms evolve rapidly, mutations lead to adaptations.

Artificial Selection

Humans breeding organisms for desired traits.

Stabilizing Selection

Selection against extreme values results in population mean remaining stable.

Directional Selection

Selection favoring one extreme leads to a shift in the population mean over time.

Disruptive Selection

Selection favoring extremes results in two populations potentially evolving into distinct species.

Sexual Selection

Selection of traits enhancing mating success resulting in dimorphism.

Cumulative Selection

Long-term accumulation of small changes leading to significant adaptations.

Altruism in evolution

Behavior that reduces individual fitness while benefiting others, often through kin selection.

Genetic Drift

Random alleles loss in small populations affecting genetic makeup.

Bottleneck Effect

Temporary population decline leading to increased genetic drift.

Founder Effect

Small population colonizing a new area, causing limited genetic diversity.

Gene Flow

Movement of individuals between populations altering their genetic compositions.

Mutations in evolution

Provide genetic variation; beneficial mutations are rare, harmful are selected against.

Reproductive Isolating Mechanisms

Processes preventing populations from interbreeding and exchanging alleles.

Prezygotic Mechanisms

Prevent mating or fertilization, including ecological, temporal, and mechanical isolation.

Postzygotic Mechanisms

Prevent development of viable offspring, including hybrid inviability and infertility.

Speciation definition

Formation of new and distinct species through reproductive isolation.

Allopatric Speciation

Geographic isolation resulting in separate species.

Sympatric Speciation

Two populations remain in contact but stop exchanging alleles due to reproductive isolation.

Divergent Evolution

Different species evolve distinct traits due to different selective pressures.

Convergent Evolution

Unrelated species develop similar traits due to similar environment pressures.

Coevolution

Mutual evolution of two species in response to each other.

Adaptive Radiation

Rapid evolution of diversely adapted species from a common ancestor.

Hardy-Weinberg Principle

Specifies conditions under which allele frequencies remain constant, indicating no evolution.

Hardy-Weinberg Equations

p + q = 1, p^2 + 2pq + q^2 = 1.

Unique traits of humans

Complex reasoning, learning, tool use, language, large brains, fine manipulative hands, bipedalism.

Hominid Evolution timeline

Bipedalism began 6-7 million years ago; Homo evolved 2 million years ago.

Changes in hominid characteristics

Increased brain size, diet adaptations, changes in pelvis and foot structure.

Human migration evidence

Patterns of human movements across the globe.

Cladogram findings

Indicates physical characteristics of human ancestors and evolutionary relationships.

Evolutionary significance of the fossil record

Shows the chronological order of species appearance and extinction.