BM108 Megans Cram

1944 Erwin Schrodinger

wrote a paper on "The Physical Aspect of the Living Cell" where he discussed a living system's biology and the physical chemistry concept of entropy.

The second law of thermodynamics

The entropy of any natural and spontaneous process either increases or remains constant.

The sun's temperature

5800K

• 13.82 BYA

The big bang

4.6 BYA

Proto earth

4.6-4.03 BYA

Hadean

3.5-3.0 BYA

Emergence of complex life

Stromatolites

Fossilised bacteria

3.0 BYA

The great oxidation event

2.0 BYA

Complex multicellular life

Triggers tides

The moon

Distance earth-moon

384,000 KM

Black smokers

Deep sea hydrothermal vents causing super heated water, and a “battery” effect

Hot springs

Made up of primordial soup with geological basic chemical constituents. Darwin’s theory of life’s origins

Living off air

Bacteria in the antarctic that survives by scavenging trace atmospheric gases

Clay’s microenvironment

provides an ordered microenvironment for complex molecules to assemble without immediate decomposition by hydrolysis

1920s Alexander Oparin

Primordial Soup’ theory: organic molecules forming in oxygenless world – triggered by UV light.

1952 Miller-Urey Experiment

• More accurately mirrored the early world's environment

• Discovered over 20 amino acids using this model

Bartel and Szotak 1933

created an experiment where they generated small RNA molecules, with different sequence of AUGC and threw them in a variety of reactions, and tried to work out if any of them could function as an enzyme.

Jeremy England experiment

Created some equaions that suggested if you have warm temperatures and water then you're always going to drive forward the production of complex chemistry and head towards life (suggesting life is inevitable)

Goldilocks zone

This is the area that's not too hot, not too cold, but just right for life to thrive. Earth falls within this zone, making it perfectly habitable for earth. (around 1 AU from sun)

Krovalev crater

(on mars) 50 mile diameter crater with solid ice with perhaps liquid at the bottom, possible for life to emerge.

Moons of Jupiter with possible life

Europa, Calliso, Ganymede

Saturn’s moons with signs of life

Titan, Enceladus

Panspermia

The theory life on earth originated elsewhere

Drakes equation (N)

Number of detectable civilizations in the milky way

Drakes equation (R*)

Rate at which stars are born

Drakes equation (fp)

The fraction of stars that host planets

Drakes equation (Ne)

Number of habitable planets per planetary system

Drakes equation (fl)

Fraction of those planets where life occurs

Drakes equation (fi)

Fraction of life that evolves intellegence

Drakes equation (fc)

Fraction of intellegence life that develops communication

Drakes equation (L)

Length of time civilisations are detectable

Fermi Paradox

If life is out there, why have we not found them?

Prokaryotes

single-celled organisms, including bacteria and archaea, that lack a nucleus and membrane-bound organelles

Endosymbiosis

a evolutionary process where one organism lives inside another, typically forming a beneficial, mutualistic relationship

Most likely bacteria to form endosymbiosis

Wolbachia

Asgardian Archea

Archea sub group

Alexander Murray

Discovered the metazoan branch of the animal kingdom in fossil

Ediacara biota

fossil found in australia showing multicellular life

How long ediacara biota existed

50-100 million years

Cambrian explosion

Boom in multicellular life when photosynthesis tipped over the atmosphere

- Theodosius Dobzhansky, 1973

"Nothing in Biology makes sense except in the light of evolution"

Charles Darwin (1809-1882)

• Travelled to Galapagos Islands in HMS Beagle when 22 observing variation in plants and animals during the 5 year voyage

• Investigated finches

Alfred Russel Wallace

Explored Malaysia in 1855, discovered the wallace line (separating asia and australia)

Selection pressure

struggle for existance/survival of the fittest

Methicillin-resistant Staphylococcus Aureus

MRSA - Bacterial infection often acquired in hospitals (e.g. after surgery), Recently patients have started failing to respond to antibiotics

Prokaryotic Bacteria

often single celled, though examples of multicellularity occur

Protists

classified into the domain eukarya and occur as single eukaryotic cells or more complex bodies; multicellularity is common, and some protists such as photosynthetic seaweeds, are quite large

Horizontal gene transfer (HGT)

commonly occurs among prokaryotic species and between domains of life fostering evolutionary diversification.

Extremophiles

Lovers of extreme conditions (such as methanopyrus which exist in deep-sea thermal vents)

Binary Fission

basis of a widely used method for detecting and counting bacteria in food, water samples, or patient fluids.

Akinetes

thick walled food filled cells produced by aquatic filamentous cyanobacteria that are able to survive winter at the bottom of lakes

Five common shapes of bacterial cells:

Cocci (spheres), bacilli (rods), vibrios (comma-shaped), spirochaetes (spiral flexible), spirilli (spiral rigid)

Peptidoglycan

important polymer component of bacterial cell walls composed of carbohydrates that are crosslinked by peptides

Biofilms

rich in the outer envelope of gram-negative bacteria

Biofilms

coating of bacterial filaments in which cells stick to each other and often also to a surface.

Two theories of evolution

Gradual (slow small changes), punctuated (long periods with no change followed by quick changes)

Zuckerland and Pauling (1962)

The molecular clock

Synteny

Describes where the same sequence are to be found between different species

6 Pieces of Evidence That Confirm Evolution

The Fossil Record, Comparative genetics, Comparative Anatomy, Speciation, Microevolution, Artificial selection

Comparitive anatomu

• Similar anatomy in related species (can be homologous or analogous)

Allopatric speciation

Geographic isolation (thought to be the most important isolating mechanism)

Types of isolating mechanisms

Geographical, ecological, temporal, behavioural, mechanical, gametic, hybrid

Ecological isolation

live in the same area but different habitats

Temporal isolation

breeding at different times

Behavioural isolation

courtship rituals different

Mechanical isolation

anatomical differences prevent mating

gametic isolation

gametes can not unite

Hybrid isolation

offspring infertile sympatric

Out of africa

Homo heidelbergenesis or other transitional forms evolved into Neanderthals and Denisovand. Hominins in China with mixtures of archaic and modern features may have derived from H. Heidelbergenesis.

Human evolution timeline

Homininae (sahelanthropus, ardipethecus, australopithecus), homo (habilis, erectus, neanderthal denisovan, sapien)

Layers visible after centrifugation

PLasma, Leycocytes, Erythrocytes, (platelets not visible)

Blood plasma

30-60& total volume, water, dissolved nutrients, hormones, proteins

Leucocytes

Defend the body against infection and disease

Erythrocyes

RBCs, 250 million haemoglobin/RBC

haemoglobin structure

contains 4 protein subunits, each one subunit contains 1 heme molecule that binds one O2 molecule (each haemoglobin can bind 4 O2)

Capillaries

Site of gas and nutrient exchange

PLatelets

PLay a crucial role in the formation of blood clots

Blood flow equation

F = ΔP/R

Pressure gradient

Difference in pressure between the beginning and end of the vessel

Resistance

Measure of hindrance or opposition to blood flow through a vessel

Relationship of flow to resistance

Resistance ∝ 1/r4

Vascular tree

Arteries, arterioles, capillaries, venules, veins

Arterioles

Smaller brances of arteries

Capillaries

Smaller brancher of arterioles, smalles of vessels across which all exchanges are made with surrounding cells

Venules

Formed when capillaries rejoin, merge to form veins

Arteries

Serve as rapid-transit passageways for blood from heart to organs. Have a large radius and low resistance. Connective tissue contains collagen and elastin fibres

Normal blood pressure

120/70

Internal core temp

37

Mechanisms of heat transfer

Radiation, conduction, convection, evaporation

Hypothalamus

acts as a thermostat

Purpose of the renal system

Forms urine, regulates blood volume and pressure, regulates plasma ion conc, regulates blood pH

Organs involved in renal system

Kidney, ureters, bladder, urethra

Metazoan

Multicellular eukaryotic organism, has cells that are specialised for specific functions

WHat most accurately shows that a species may have had a comon ancestor

Anatomical Homologies, Molecular Homologies and Development Homologies

Sympatric isolation

Occurs within populations in the same geographical isolation

Microevolution

Change in allele frequency in response to environmental pressure

Which is not part of the human evolution timeline (but is part of the early ape species)

Australopithecus

During which stage of embryonic development does the amniotic cavity form?

Making the two blast cell layers