evolving earth Flashcards
difference between residential and predatory boring
Residential is smaller and simpler in structure whereas predatory is irregular in size and shape and strategically placed to capture prey
identify stromatolite and how they are made
stromatolites have distinctive layered or banded appearance with a conical or domical shape. Cyanobacteria and other microbial communities form slimy mats in shallow water environments. These mats can trap and bind sediment often found in specific geological settings, such as shallow marine environments, coastal areas
explain body fossil
Remains of the actual body parts of an organism, such as bones, teeth, shells, or soft tissues. can be identified from structures from the organism’s body, such as skeletal elements, imprints, or casts.
what is a trace fossil
Evidence of an organism’s activity, behavior, or presence rather than its actual body parts. Examples include footprints, burrows, and coprolites (fossilized feces).
what is a chemofossil
Fossils that are not composed of organic material but instead involve the preservation of chemical signatures, such as isotopic ratios or molecular biomarkers
explain pseudofossil
Geological formations or patterns that might be mistaken for fossils but are not the result of past living organisms.
expain abiological material fossil
Non-living material that is not considered a fossil, as it did not originate from a once-living organism
describe high and low energy deposition for sediment size
Coarse-grained, well-sorted sediments (e.g., well-rounded sand) often indicate a high-energy environment where strong currents or waves can transport and sort larger particles. Fine-grained, poorly sorted sediments (e.g., clay or silt) are typical of low-energy environments with slower-moving water, where finer particles settle out more easily
describe high and low energy deposition for bedding structure
Cross-bedding, ripple marks, and channel deposits suggest dynamic conditions, commonly found in high-energy environments like rivers, beaches, or shallow marine settings. Horizontal bedding, laminations, and mudcracks are associated with calmer, low-energy environments such as lakes, tidal flats, or deep marine basins
describe high and low energy deposition for preservation of fragile features
Delicate structures like delicate shells or fine details may be less well-preserved for high energy due to the abrasive action of water and sediment movement. Delicate structures are more likely to be preserved in low-energy environments where sediments settle more gently
describe permineralisation
Minerals fill the pore spaces of the organic material, creating a fossil with mineralized tissues. The original structure is often preserved, and the fossil may be heavier due to mineral infill
describe unaltered hard parts
The original hard parts of an organism, such as shells or bones, remain unchanged over time. Fossils retain their original composition and structure.
describe recrystalisation
Original minerals are replaced by larger crystals of the same mineral. Fine details may be lost, and the fossil may appear more crystalline
describe impression/mould
The organism’s remains dissolve, leaving an impression (negative imprint) in the surrounding sediment. Moulds are hollow spaces that replicate the external shape of the organism
describe compression/carbonisation
Organic material is flattened and reduced to a thin film of carbon. Fossils may appear as dark imprints on a lighter background, retaining surface details but lacking three-dimensional structure.
