4.2.2 Classification And Evolution Flashcards
What is the importance of classification?
Allows
identification of new species
Study of evolutionary relationships
Understand adaptations
What is the importance of the binomial naming system?
Avoids miscommunication when using regional common names. Names are same around the world
What are characteristics of prokaryotae
Prokaryotic
Unicellular
No membrane bound organelles
Peptidoglycan cell walls
Can be autotrophic, heterotrophic or parasitic
Stores sugar as glycogen
Reproduces via binary fission
What are key features of animalia?
Eukaryotic
Multicellular
Membrane bound organelles
No cell walls
Heterotrophic
Glycogen sugar store
Gametes for sexual reprodcution
What are key features of plantae?
Eukaryotic
Multicellular
Membrane bound organelles including chloropasts
Autotrophic
Cellulose cell walls
Sugar stored as starch
Reproduce using seeds or spores
What are key features of fungae?
Eukaryotic
Can be unicellular or Multicellular
Has membrane bound organelles
Chitin cell walls
Saprophytic
Sugar stored as glycogen
Reproduce using spores
What are key features of protoctista?
Eukaryotic
Unicellular or Multicellular
Has membrane bound organelles some have chloropast
Can have cell walls
Can be autotrophic, hetertrophic or parasitic
Can store sugar in multiple forms
Has variable ways to reproduce
What is a setback of classifictaion?
Scientific knowledge and understanding is constantly developing meaning old methods can be outdated ( eg five kingdoms three domains)
Taxonomy is periodically updated and reorganised to reflect this
What are the three domains?
True bacteria- found in all environments, prokaryotic unicellular organisms with distinct cell membrane lipids and peptidoglycan cell walls with unique RNA polymerase.
Archaea- found in extreme environments, prokaryotic unicellular organisms, have histones, no peptidohlycan cell walls, cell membrane contains ether bonds between fatty acids and glycerol and has a more complex RNA polymerase.
Eukarya- contains four kingdoms with all cells containing nuclei and membrane bound organelles
What is phylogeny?
Based on evolutionary relationships between organisms and ancestors. Produces continuous tree with no spe fiction taxonomic groups, no overlap. Indicates lines of descent and divergence overtime
What are the improvements of classification from previous methods?
Old methods involved classes based on anatomical difference and similarities which is not always reliable due to convergent evolution, this misreprents evolutionary relationships.
What are modern techniques used to classify organisms?
Molecular comparisons- DNA and amino acids in proteins like cytochrome C which is a protein shared across most eukaryotes, used in respiration
Developmental studies- comparisons of embryonic development, similarities and differences
Anatomical examinations- comparisons of similarities in species physical characteristics (fossil analysis)
Behavioural analysis- comparisons of similarities and differences between behaviour of species
Why is the fossil record incomplete?
Most organisms decompose before fossilisation
Very specific conditions are needed
Fossils can be lost by erosion
Soft bodies organisms unlikely to fossilise
Why are fossils useful?
Paleontology shows how organisms have gradually changed over time.
Simple bacteria and algae found in deepest rocks with complex vertebrae found in newer rocks
Plants fossils deeper than animals showing plants inhabited first
What is comparative anatomy?
Homologous structures with similar underlying structure but have different functions
Organisms sharing homologous structures likely to have evolved from a common ancestors
Evidence for divergent evolution
What are methods of comparative biochemistry
Cytochrome C- highly conserved protein for Aerobic respiration
rRNA- important for protein synthesis so rate of change is very slow
DNA- more closely related species have more similar dna sequences
mRNA- base sequences complimentary to DNA
Amino acids
What is neutral evolution?
Most variability does not effect function (non coding sections of dna)
Accumulates regularly
Allows scientists to estimate time since species diverged from common ancestors
More differences means more ancient divergence
What are the different types of variation?
Anatomical- physical structures which aid survival. Body coverings, camouflage, mimicry
Behavioural- actions which increase survival. Defensive responses, courtship displays, migration and hibernation
Physiological- internal processes to help survival. Venom, water storage or release of antibacterials
What are analogous adaptations?
Serve similar functions but originate from different evolutionary paths.
Example of convergent evolution
What is convergent evolution?
Unrelated species develop similar traits adapting to a similar environment with similar selection pressures.
What is the process of natural selection?
Variation in characteristics within a species
Individuals with advantageous alleles survive and are more likely to reproduce
Advantageous alleles passed down to offspring
Allele frequency increases in population overtime.
