L3: UNIVERSE AND COSMOLOGY IN THE CONTEXT OF EVOLUTIONARY BIOLOGY

Relevance of cosmology in evolutionary biology

• life depends on universe’s laws

• stars create the elements of life

• planets form in cosmic processes

• biology is written in cosmic history

Stars

it created the elements of life

The Standard Model

the primary scientific theory that classifies all known elementary particles and explains three of the four fundamental forces of the universe: electromagnetism, the strong nuclear force, and the weak nuclear force

Quarks, leptons, bosons

Fundamental particles (3), building blocks of matter

Electromagnetic, strong nuclear, weak nuclear, gravity

Forces in Nature (4)

Protons

Made up of quarks and Gluons

Molecule

Everything in the universe are made up of these

Atom

consist of a core and multiple electrons

Nucleus

Core is made up of Protons and Neutrons

Higgs Boson

an elementary particle in the Standard Model of particle physics. It is the visible quantum excitation of the universal Higgs field, an invisible energy field that gives mass to fundamental particles like electrons and quarks through their interactions with it

Higgs Field

Acts as a syrup that slows down the protons and start to clot forming Matter

Does not explain dark matter and dark energy, and can’t unify gravity

Limitations of the standard model (3)

Big Bang Theory

• Universe began 13.8 billion years ago

• Evidence: redshift, cosmic microwave background

Inflationary Universe

• Rapid early expansion

• Explains uniformity of cosmos

Steady State Theory

• universe has no beginning

• now considered outdated

Multiverse Idea

Many possible universes, each with different conditions

Quantum Fluctuations

• Tiny energy changes created matter

• Possible origin of “something” from “nothing

Big Freeze

(also called the Heat Death or Big Chill) is a scientific theory about the ultimate fate of the universe. It suggests that as the cosmos expands forever, heat and energy spread out completely. Eventually, stars burn out, galaxies drift apart, and the universe reaches a cold, dark, and silent state just above absolute zero.

Big Crunch

a scientific theory about how the universe could end. It states that gravity will one day stop the expansion of space, pull all matter and energy backward, and crush everything into a tiny, hot, super-dense point known as a singularity.

Big Rip

a hypothetical cosmological scenario where the accelerating expansion of the universe becomes so extreme that it tears apart all matter and spacetime itself

Heat Death

• entropy increases

• stars burn out no usable energy left

Fine-tuning

means that the physical laws, cosmic constants, or biological traits must fall within an extremely narrow, precise range for life to exist.

Anthropic Principle

• a concept in cosmology and philosophy stating that our observations of the universe must be compatible with the conscious life that is doing the observing

• We observe it because we exist

Gravity strength, nuclear forces, cosmic expansion rate

Examples of fine-tuning

The Goldilocks Zone

Region where liquid water exists

Sun’s habitable zone

• Earth sits perfectly at ___

• Allows oceans and stable climate

Solvent, Biochemical reactions

Water matters because it is the____for life’s chemistry and medium for ___

Carbon, Hydrogen, Oxygen, Nitrogen, Sulphur, Phosphorus

Essential elements (6)

Sunlight, geothermal, chemical energy-extreme environments

Energy sources (3)

Atmosphere

shields from radiation and helps regulate temperature

Troposphere, stratosphere, mesosphere, thermosphere

Atmosphere (4)

Mercury, Venus, Earth, Jupiter

Planet order from least to greatest relative gravity

Planetary Size & Gravity

• Must hold atmosphere

• Maintain stable surface conditions

Role of Plate Tectonics

• Carbon cycle balance

• Temperature regulation over time

Mars

• once had water

• too thin atmosphere today

Europa

• Subsurface ocean

• Possible microbial habitats

Stromatolites

created by microbial mats, primarily composed of photosynthetic microorganisms like cyanobacteria

Microbial mat growth, sediment trapping, upward growth, layering

How stromatolites form (4)

Cyanobacteria

absorbs carbon dioxide and release oxygen, and this process is key to their historical significance

2.7 billion years ago

Estimated appearance of cyanobacteria

Great Oxygenation Event

occurred about 2.4 to 2.1 billion years ago. Cyanobacteria evolved the ability to perform oxygenic photosynthesis, releasing free oxygen that poisoned anaerobic life, destroyed atmospheric methane, and triggered the Huronian glaciation.

Grazing Organisms

Stromatolites are now rare due to them being vulnerable to ___ that evolved after the Precambrian era