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Evolution & Life on Earth - Coggle Diagram
Evolution & Life on Earth
What is Species/How do we label
Biological Species Concept
A species is a group of populations whose members can interbreed and produce viable, fertile offspring/Babies have babies
Con: Does not work on bacteria or fossils/Not everything leaves fossils extremely biased, does not consider Asexual Organism
Morphological
Based on how they look and their appearance
Con: Often very deceiving think of how a dolphin and shark look alike DNA is very distant
Ecological
Based on where they live
Con: Often abused by biologist so they can claim they discovered a new kind of species
Phylogenetic
Based on DNA data
Con: Requires precise Information therefore gray area as what constitutes as waht
Reproductive Isolation/ Biological barriers that prevent species from interbreeding
Prezygotic & Postzygotic Barriers
Prezygotic Barriers: Prevent fertilization
Habitat Isolation: Different environments
Berry Bugs/one likes bark other fuits
Temporal Isolation: Different mating times
Skunks/Autum V. Spring
Behavioral Isolation: Different mating behaviors
Blue Footed Bird/Has to do a silly dance
Mechanical Isolation: Incompatible reproductive structures
2 Snails/cannot physically mate Part A does not go w Part B
Gametic Isolation: Sperm can't fertilize egg
Dog & Cat/Just does not sound right
Post-zygotic Barriers/All deal with "Hybrid"
"Hybrid" organism that is the offspring of two different species
Reduced Hybrid Viability: Offspring doesn’t develop properly.
Salamanders
Reduced Hybrid Fertility: Offspring is sterile
mules
Hybrid Breakdown: Future generations are weak or sterile
Rice plant
What Happens when Hybrids are Created
Hybrid Zone
Area where two species meet and interbreed.
Reinforcement
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Fusion
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Stability
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How are new species created/Speciation This is the formation of new species
Geographic Isolation & Allopatric Speciation
Allopatric Speciation: Speciation due to physical separation/“Other Country”
Geographic Isolation: Mountains, rivers, etc.
2 different species created in Grand Canyon as squirrels cannot travel easily
Genetic drift and natural selection drive divergence.
Darwin’s finches on different Galápagos islands/Flightless Commondor
Sympatric Speciation without geographic separation/“Same Country”
Polyploidy
A species may originate from an accident during cell division that results in extra sets of chromosomes, a condition called polyploidy/THINK OF PLANTS
Autopolyploid: From one species.
Allopolyploid: From hybridization between species.
Why Common in Plants: Plants can self-fertilize and tolerate chromosome changes better than animal
Errors in meiosis or fertilization
Sexual Selection
Preference for certain traits in mates
Cichlid fish choosing mates based on color in the/Same Fish @ TCC
Cultural or social preferences may influence mate choice, possibly leading to subtle reproductive isolation.
sexual dimorphism
males and females of the same species look different—often in size, color, shape, or behavior
Habitat Selection
Subpopulations exploit different resources.
Apple maggot flies preferring apples vs. hawthorns
How Long does it take?
Gradual vs. Punctuated Speciation
Gradualism: Slow, continuous change.
Punctuated Equilibrium: Sudden change followed by stability.
Supported by fossil record.
Rapid appearance of new species after mass extinction.
From Speciation to Macroevolution
Macroevolution
This refers to large-scale evolutionary changes that occur over long periods of time, above the species level.
Speciation is the building block of macroevolution
How Did life on Earth First Start
Conditions on Earth made life possible
According to one hypothetical situation there were 4 main stages
1,Abiotic Synthesis of Organic Molecule
The abiotic (nonliving) synthesis of small organic molecules, such as amino acids and nitrogenous bases
Joining of Monomers into Macromolecules
Small molecules (monomers) link to form complex molecules (macromolecules) like proteins and nucleic acids
The packaging of these molecules into protocells
Origin of Self-Replicating Molecules
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(droplets with membranes that maintained an internal chemistry different from that of their surroundings)
Liposomes, Simple vesicles formed from lipids in water
Key Because/Provided a protected environment for chemical evolution.
Must be noted experiments have been able to create anything like nucleotides
Lab simulations show amino acids can polymerize on hot clay surfaces or near hydrothermal vents.
Dripping solutions of amino acids onto hot sand/ leads to spontaneous formation of polypeptides.
Key Because/Macromolecules are essential for structure and function in cells.
All living cells contain an array of macromolecules including enzymes other proteins and nucleic acids,
Must be Noted that this scenario is speculative but does lead to predictions which can be tested
Conditions on Early Earth
Atmosphere: Rich in H₂O, CH₄, NH₃, H₂, CO₂/ Must note no oxygen
Lightning, UV radiation, volcanic heat.
Miller-Urey Experiment (1953)
Simulated early Earth conditions using a closed system.
Passed electric sparks (lightning) through a mixture of gases.
After a few days, found amino acids (glycine, alanine, etc.).
Amino Acids
Non-living molecules: Building blocks of proteins.
Can form spontaneously from simple gases.
Do not replicate or metabolize—just chemical structures.
Made a Breakthrough Organic molecules can form spontaneously under early Earth conditions.
Formed about 4.6 billion years ago
No ozone layer
Russian chemist A. I. Oparin and British scientist J. B. S. Haldane independently hypothesized that Earth’s early atmosphere was a reducing
What other evidence tells the story about life on Earth?
The Fossil Record documents the history of life/must be noted it is incomplete
There Have been great changes to Earth
Many past organisms were unlike living organism
Many organims that were once common are now extinct
New groups or organism arose from previous ones
Radiometric Dating
Measures decay of isotopes (e.g., Carbon-14, Uranium-Lead).
Fossils contain isotopes of elements that accumulated while the organism was alive
Carbon 14 is useful for dating fossils up to about 750,000 years old/Only works on organic material.
Radioactive isotopes decay at a known rate (half-life).
By measuring the ratio of parent to daughter isotopes, scientists calculate the age.
Uranium-238,Used for dating very old rocks.
Provides absolute ages of fossils and rocks.
Stratigraphy
Study of rock layers (strata) and layering.
Why Dating Matters
Places fossils and evolutionary events in a timeline.
Helps reconstruct Earth's biological and geological history.
Essential for understanding mass extinctions, speciation, and environmental changes.
Flaws of the Fossil Record
Few organims are preserved in Fossils
Many Fossils that do form end up Destroyed
Only Hard things make Fossils/No bacteria
Animal Had to live for several generations
The fossil record shows how new groups of organisms can arise via the gradual modification of preexisting organisms.
More Evidence of the Earth
Geological Time Scale/The geological time scale organizes Earth’s history into a hierarchy of eons, eras, periods, and epochs, based on major biological and geological events.
Hadean Eon (~4.6–4.0 billion years ago)
Archean Eon (~4.0–2.5 billion years ago)
Proterozoic Eon (~2.5 billion–541 million years ago)
Paleozoic Era (541–252 million years ago)
Mesozoic Era (252–66 million years ago)
Cenozoic Era (66 million years ago–present)
Age of Mammals: Mammals diversify and dominate.
Primates and humans evolve.
Continents shift to current positions.
Cretaceous–Paleogene Extinction (~66 million years ago)
Age of Reptiles: Dinosaurs dominate.
First mammals and birds appear.
Breakup of Pangaea
Rifting and divergence of tectonic plates.
Formation of modern continents.
3.Permian–Triassic Extinction (~252 million years ago)
4.Triassic–Jurassic Extinction (~201 million years ago)
Cambrian Explosion: Rapid diversification of marine life.
/Hard bodied organism
First vertebrates, land plants, insects.
1.Ordovician–Silurian Extinction~444 million years ago
2.Late Devonian Extinction~375 million years ago
very important was the Oxygen revolution due to photosynthesis/Due to cyanobacteria
First eukaryotic cells.
First multicellular organisms.
First life: prokaryotic cells (bacteria).
Anaerobic atmosphere (no oxygen).
Earth forms.
Surface is molten; no life.
Pangaea & Plate Tectonics
Plate Tectonics
In plate tectonics, continental plates move gradually over time, altering the physical geography and climate of Earth, leading to extinctions in some groups and speciation in others.
Formation of PangaeaA supercontinent that included almost all landmasses on Earth.
Altered global climate and ocean currents.
Reduced coastal habitats.