EVOLUTION Flashcards
define fossil
any preserved trace left by an organism that lived long ago
define the 4 steps involved in fossil formation
- Death and decay
- Rapid burial
- Permineralisation
- Erosion and Exposure
define 4 optimal conditions for fossil formation
- Rapid Burial
- Alkaline soil conditions
- contains hard body parts - bone, teeth, shell
- absence of decaying microorganisms
define artefacts
objects made by humans
eg. stone tools, carvings, paintings
what are 4 problems with the fossil record
- fossils aren’t found yet
- fossils cannot be dated
- didn’t get fossilised
- only some parts of organism was fossilised
what are 2 dating techniques of fossils
absolute dating
relative dating
define absolute dating
finding out the actual age of specimen in years
define relative dating
comparing of fossils to tell us whether the specimen is older or younger than another fossil
what is the half life for Potassium Argon Dating
1.25 billion years
what occurs over time for potassium argon dating to be measured
potassium-40 levels decrease
argon-40 levels increase
what is potassium argon dating used for
dating volcanic rocks, not fossils
what age can potassium argon dating be used to date fossils
samples older than 100,000-200,000 years old
what occurs overtime in carbon-14 dating
carbon-14 levels decrease, Nitrogen-14 increase
what is the half life for carbon-14 dating
5730 years
what is radiocarbon dating used to date
anything that used to be living (contained CO2)
define stratigraphy
study of layers (strata)
what are the two types of stratigraphy
principal of superposition
correlation of rock strata
what does the principal of superposition assume
assumes that in layers of sedimentary rock, the layers at the top are younger than the layers beneath
what is a limitation for the principal of superpostition
animals/humans sometimes bury artefacts /fossils - placing them deeper leading to an inaccurate assumption of their age
what occurs in the correlation of rock strata
involving matching layers of rock of similar age from different areas
define index fossils
living things that were present on earth for a short amount of time and are widely distributed on earth
define evolution
the gradual change in characteristics of a species overtime
define speciation
two populations because different enough through evolution that they can no longer interbreed to form new species
define comparing dna
the sequences/order of nitrogenous bases in a dna sequence are analysed for similarities
what occurs in comparative genomics
the complete set of dna in a cell of an organism is analysed
what are endogenous retroviruses
stretches of non-functioning dna
sequences of dna that have become part of an organisms genome when an ancient virus inserted its genetic material into a cell
why do we compare mitochondria in comparative studies
mtDNA is inherited from an individuals mother
allowing to trace back to maternal common ancestor
what can be analysed in protein sequence comparing
sequences in which proteins are joined
compare type and sequence of amino acids in similar proteins
what are proteins found in all species called
give an example
ubiquitous proteins
cytochrome C - cellular respiration
define bioinformatics
used to align the sequences and find similarities and differences in dna sequences through computer analysis
define the importance of comparative embryology
comparing the early stages of development in organisms
strong similarities in embryos at different times for different species evolving from a common ancestor
define what homologous structures
similar structures in anatomy that are inherited by common ancestors
ex. pentacle limb structure
define what is meant by vestigial structures
structures of reduced size that don’t have a function
remains of organs that once functioned in ancestral forms but overtime, due to changing environments and living conditions, their function became non-essential
