Fossil
the preserved remains and traces of past life
They provide evidence of past life
these remains can be hard parts, such as teeth, bones and shells, or impressions in the rock where the organism’s tissue has decayed.
Palaeontology
study of fossils
Fossils shows that there has been a clear change over time from simple to very complex organisms, which is evidence of evolution
process of fossilisation
- Organic matter quickly deposited and covered in sediments in an environment that lacks oxygen, preventing decomposition
- Minerals from sediments replace the natural bone/shell material, hardening the fossil.
- Organisms covered with sedimentary materials. Materials consolidate to form sedimentary rock
- Long period of time
Principle of superposition
indicates that the oldest rock layer is found at the bottom of the rock, with each consecutive layer above being relatively younger
Transitional forms
the Arhaeopteryx was a small flying dinosaur with feathers.
It appeared in late Jurassic period
it shared features in common with both birds and reptiles.
Its reptile like features include a long tail, claws, no keel, solid bones, and teeth.
it bird like features include a wish-bone, feathers and reduced fingers.
Fossil dating methods
relative dating - used to determine age of the rock, or fossil contained in the rock, relative to other rocks or fossils found nearby. Strata are deposited in a time sequence with the oldest on the bottom and the youngest on top. Paleontologists can assign relative ages to fossils based on the strata in which they are found.
Absolute dating - assigns a numerical age in years to a fossil or rock. 3 main types: radiometric dating, electron spin resonance and luminescence. Most common method of absolute dating is radiometric dating, which uses the known rates of decay of naturally occurring radioactive isotopes present in a rock or fossil.
Comparative anatomy
study of the similarities and differences in structure between different organisms.
Structural features are also called morphological features.
used to establish evolutionary relationships on the basis of the structural similarities and differences, including the comparative study of embryos
Pharyngeal slits
gill slits
Homologous structures
anatomical structures that are common to more than one species and were inherited from a common ancestor, but have different functions, are known as homologous structures.
Show the same structural plan but perform different functions due to the different species living in different selective pressures (conditions)
vestigial homologous structures
Homologous structures stemming from a common descent can eventually cease to have any functional use for an organism.
structure may not necessarily impede a particular adaptation of an organism, but at the same time the structure no longer serves a ‘useful’ purpose.
Can take a variety of forms, including bones, soft tissues, organs
Analogous structures
features of organisms that have the same function but not the same basic structure
Identification technologies
used to accurately trace the genetics of desirable traits and to pass those traits to other plants within a generation.
Can examine DNA of seeds to find the ones that will produce the best plants.
transformation
Taking a gene from one species and inserting it into another to obtain a desired characteristic.
Achieved through: recombinant DNA technology, transgenic organisms.
Transfer of genes
done through gene gun or viral vector
Reason to genetically modify
to produce more product
To make them model organisms for studying human disease and for discovering the functions of various genes
To build resistance (drought, chemicals, temperature)
Conservation biology
integrated study of ecology, physiology, evolution, molecular biology and genetics wt a view to sustaining biological diversity at all levels.
Biotechnology used for: monitoring endangered species, assessing gene pools for breeding programs, quarantine.
Biological diversity
3 levels: genetic, species, ecosystem diversity
Gene pool
collection of all the alleles for all genes in the reproducing members of a population at a given time
Conservation planning considerations
- biogeography - if distribution of a species changes over time, helps determine whether or not an area needs active protection, restoration or management.
- Reproductive behaviour - considered to avoid inbreeding and loss of advantageous alleles, gene pool diversity, and reproductive fitness.
- Population dynamics - study of the number, gender, age and relatedness of individuals in a population. Directly affected by the number of births, deaths, immigrations and emigrations.
Environment DNA
(eDNA)
DNA left behind in an environment by an organism
quarantine
The isolation of organisms that have arrived from elsewhere or been exposed to an infectious or contagious disease.
Bioremediation
Consumption and breakdown of environmental pollutants by deliberately introduced or naturally occurring micro-organisms
biodegradation
Breakdown of an organic substance by micro-organisms such as bacteria through decomposition
superweed
A species of plant, transformed by a gene from a GMO to increase its growth rate, disease resistance or tolerance of environmental limits, that has become difficult to control.
