WEEK 4 - Fossils and Mythology Flashcards

Question

🐦 Stone Swallows: Fossils Misunderstood as Birds

Answer 1

Ancient Chinese once interpreted some fossils as “stone swallows” 5th-century scholar Li Taoyuan recorded that during thunderstorms, these stones flew as if they were real birds Likely fossilized remains of ancient marine life, not birds

Answer 2

Thought to be fossilized birds ("stone swallows")

Answer 3

Actually the tail (pygidium) of trilobites Trilobite classification: - Phylum: Arthropoda - Class: Trilobita

Answer 4

Believed to be urine that turned to stone Chemist Robert Plot: Thought frozen crystals of urine shot from a center

Answer 5

Actually a type of clam shell Classification: - Phylum: Mollusca - Class: Pelecypoda/Bivalvia

Answer 6

Coiled fossils believed to be snakes turned to stone Legend of St. Hilda (614-680 AD): - A religious figure in Whitby, England - Captured snakes, severed their heads, and turned them to stone

Answer 7

Actually ammonite fossils (extinct squid-like creatures) Classification: - Phylum: Mollusca - Class: Cephalopoda - Modern Relative: Nautilus

Answer 8

The process is extremely finicky <5% of all living remains make it into the fossil record Most fossils are hard tissues (bones, shells, teeth) Requires exceptional conditions + luck

Answer 9

After death, soft tissues are quickly destroyed If remains are left exposed, fossilization is unlikely

Answer 10

1️⃣ Large scavengers → Consume soft tissues 2️⃣ Smaller scavengers → Take care of scraps

Answer 11

Cellular & molecular-level decay Fungi consume soft tissue (can even grow through the remains) Bacteria break down organic matter further

Answer 12

Physical weathering → Breaks down mineralized tissues (e.g., bones, shells, teeth) Chemical weathering → Dissolves mineralized tissues over time Exposure at the surface → Increases erosion risk

Answer 13

Hard parts (bones, shells, teeth) are more chemically stable They resist destruction better than soft tissues (skin, muscle) ⚠️ But…hard parts are rarely preserved intact!

Answer 14

💀 Decomposition weakens structure Soft tissue decay removes connective tissue holding bones together Disarticulation → Bones separate after death Fragmentation → Bones break into smaller pieces

Answer 15

Even hard parts can decay over time due to: Dissolution → Minerals dissolve in hard parts Abrasion → “Sandblasting” wears them down Decay of organic components weakens bones, making them prone to breakage

Answer 16

Dissolution → Acidic water dissolves shell details Abrasion → Rounds and smooths broken shell edges

Answer 17

Nautiloid shells lined up → Unidirectional currents → Water flowed in one direction (steady current) Clam shells facing up → Bidirectional currents → Water moved back and forth (waves)

Answer 18

Limestone containing fossilized nautiloids Polished & used decoratively (e.g., furniture, tabletops)

Answer 19

Chambered structure of the fossils Natural alignment of fossil remains Light-colored calcite contrasts with dark matrix Texture contrast (polished fossils vs. rough matrix)

Answer 20

Low oxygen → Slows decay, discourages scavengers Rapid burial → Prevents scattering & protects remains Stable mineral precipitation → Strengthens remains

Answer 21

Calcium carbonate → Unstable in aragonite, stable in calcite Silica → Highly stable, found in sponges & micro-organisms Calcium phosphate → Very stable, main component of bones & teeth

Answer 22

Hard parts (shells, teeth, bones) made of stable minerals (calcite, silica) can stay unchanged Soft tissues rarely preserve, but it can happen under special conditions

Answer 23

Brachiopod shells (375 million years old) are still made of original calcite Aragonite, a less stable form of calcium carbonate, sometimes survives Ammonites (squid-like molluscs) can preserve their pearly nacreous layer (mother of pearl)

Answer 24

Refrigeration: Freezing keeps skin, flesh, and fur intact (e.g., baby mammoth) Amber Entombment: Organisms trapped in tree resin (e.g., ants, tree frogs, lice) are sealed from decay

Answer 25

Fossils often undergo physical or chemical changes after burial

Answer 26

1. Recrystallization – Crystals grow larger for stability 2. Petrification/Permineralization – Minerals fill pores in bones or wood 3. Replacement – Original material replaced by new minerals 4. Carbonization – Organic material compressed into a carbon film

Answer 27

After burial, crystals grow larger due to heat & pressure Example: - Aragonite clam shell converts to calcite with larger crystals (losing some fine details)

Answer 28

How does permineralization preserve fossils? Mineral-rich water fills small pores in bones or wood Common minerals: Silica, calcite, chalcedony Examples: - Petrified dinosaur bone (pores filled with silica) - Petrified wood (silica replaces organic material)

Answer 29

💎 Why are some fossils valued for jewelry & art? Petrified wood & bones can contain precious minerals like: - Opal (silica with water) - Chalcedony (fine crystalline silica) Used in rings, pendants, and decorative pieces

Answer 30

Original organic or mineral material is replaced by another mineral Happens at a microscopic level in sediment-rich water Common replacement minerals: - Silica (SiO₂) - Pyrite (iron sulfide, FeS₂) - Apatite (calcium phosphate, Ca₅(PO₄)₃)

Answer 31

Silica (SiO₂) replaces calcite in shells & coral Examples: - Brachiopods (delicate spines replaced by silica). - Coral (originally aragonite, now silica, cut & polished into jewelry)

Answer 32

Pyrite (FeS₂) replaces original material, giving fossils a metallic look Common in low-oxygen environments (swamps, deep-sea sediments) Examples: - Pyritized brachiopods (originally calcite). - Pyritized ammonite shells (used in jewelry)

Answer 33

Fossils can rarely be replaced by beryl (emerald variety) Example: - Gastropod shell replaced by emerald

Answer 34

Apatite (Ca₅(PO₄)₃) replaces original material, especially cartilage & bone Examples: - Shark vertebrae (originally cartilage, now apatite) - Fossilized shark teeth (enriched by phosphate from sediment)

Answer 35

🔥 How does carbonization preserve fossils? Organic material loses oxygen & hydrogen, leaving behind carbon Occurs under low heat & pressure (e.g., buried plant matter) Common in swampy environments → forms coal

Answer 36

Plant material (e.g., fern leaves) Compressed organic remains turn into thin carbon films Coal is an example of fossilized plant material

Answer 37

Jet is a gemstone variety of coal Forms from fossilized Araucaria tree wood, subjected to heat & pressure Used in jewelry & decorative items

Answer 38

A fossil mould forms when an organism's hard parts dissolve after being buried in sediment Leaves behind an empty imprint of the original structure

Answer 39

External mould → Outer impression of an organism Internal mould → Sediment fills the inside of a shell before it dissolves, leaving a cast of its interior Example: - Ammonites & gastropods often show both types!

Answer 40

When an external mould gets infilled by sediment or minerals Creates a replica of the original organism Example: - Tree trunk cast, gastropod shell cast filled with chalcedony

Answer 41

External mould = the hollow chocolate bunny mould Cast = the chocolate bunny itself (filling the mould)

Answer 42

1️⃣ The planispiral (2D spiral) 2️⃣ The helix (3D spiral) 3️⃣ The hexagon 4️⃣ Fractals These patterns appear in both living and fossil organisms!

Answer 43

A flat spiral seen in many organisms, both modern & ancient Often follows the Golden Spiral (Fibonacci sequence) Examples: 🐚 Nautilus, ammonites, ramshorn snail, foraminifera, millipedes, fern shoots

Answer 44

A stretched, lop-sided spiral instead of a flat one Seen in many biological & natural structures Examples: 🐏 Ram horns, 🧬 DNA, 🌀 Tornadoes, 🦠 Bryozoans, 🌿 Plant tendrils

Answer 45

Maximizes space efficiency Maximizes structural integrity Minimizes stress in structures Examples: 🍯 Honeycombs, 🦴 Fossil coral, 🦖 Dinosaur skin, 🌋 Basalt columns

Answer 46

A geometrical shape made up of identical parts that resemble the overall pattern The term "fractal" was coined by Benoit Mandelbrot in the 1970s

Answer 47

Repeated self-similarity → Smaller copies of the shape appear within itself This pattern continues infinitely in smaller and smaller scales

Answer 48

1️⃣ Start with one rectangle. 2️⃣ Add two smaller rectangles beneath it. 3️⃣ Repeat the process with each new smaller rectangle. 4️⃣ Keep repeating → The pattern expands infinitely!

Answer 49

Nature → Snowflakes, tree branches, coastlines Mathematics → Mandelbrot Set, Cantor's Bar Set Technology → Computers generate complex fractals using equations

Answer 50

A famous fractal discovered by Benoit Mandelbrot Self-similar patterns appear at different scales when zoomed in Based on the equation: Zn+1 = Zn² + C

Answer 51

Zooming in reveals repeating patterns within the shape Each level contains the same structure at different scales Seen in nature & mathematics!

Answer 52

Oldest known complex animals (~575 million years old) First experiment in multicellularity Found in Spaniard’s Bay, Newfoundland

Answer 53

Complex, fractal-like patterns in fossilized ammonite shells Similar to mathematically generated sutures Helped strengthen the shell while allowing flexibility

Answer 54

Trees (branching structure) Romanesco broccoli (self-repeating spirals) Lungs (bronchi & bronchioles) Stream valleys & snowflakes Mineral dendrites

Answer 55

Fossil ferns show natural fractal-like growth The Barnsley Fern is a mathematical model of fractal patterns in ferns

Answer 56

Elm trees and other plants grow in repeating patterns Fractal models can simulate tree branching