Chapter 10 Classification And Evolution Flashcards
What is classification?
The process of organising living organisms into groups based on similar features
What is the Taxonomic classification system?
Seven classification groups ordered in a hierarchy
Name the order of the seven Taxonomic groups
Kingdom (largest)
Phylum
Class
Order
Family
Genus
Species (smallest)
What taxonomic group was added into the classification system?
Domain
Added above kingdom
Why do scientists classify organisms?
-Identify the species and the group it belongs to
-Predict characteristics of a species
-Find evolutionary links between species
Why is a single classification system used?
This means scientists worldwide can share their research and links between different species can be made.
What is a species?
A group of organisms that can reproduce to produce fertile offspring.
How are organisms named using binomial nomenclature?
First name= Genus
Second name= species (specific name)
What is important to remember when using binomial nomenclature to name organisms?
Genus name is capitalised
Species name is lowercase
The handwritten name means the entire name should be underlined.
Why is the classification system of binomial nomenclature used?
Universal naming system that allows scientists worldwide to be able to understand what species are being referenced.
What does it mean two organisms share the same taxonomic name?
They are related through a common ancestor
What are the five kingdoms?
Prokaryotae (bacteria)
Protoctista (unicellular eukaryote)
Fungi
Plantae
Animalia
How did the five kingdoms classify organisms?
Organisms were classified into these kingdoms based on similarities in their observable features.
State the general features of a Prokaryotae
Unicellular
No nucleus or other membrane bound organelles
Small ribosomes
No visible feeding mechanism
(nutrients obtained through cell wall or produced internally via photosynthesis)
State the general features of a Protoctista
Unicellular
Contains a nucleus and other membrane bound organelles
Some have chloroplasts
Nutrients obtained through photosynthesis- Autotrophic
Or ingestion of other organisms
Heterotrophic
Or both
Can be sessile (immobile) while others move via cilia or flagella
State the general features of Fungi
Unicellular or Multicellular
Contains a nucleus and other membrane bound organelles
Cell wall composed of Chitin
No chloroplasts
No mechanisms for locomotion
Mycelium made of threads or hyphae
Stores food as glycogen
Nutrients obtained absorption (saprophytic feeders)
State the general features of Plantae
Multicellular
Contains a nucleus and other membrane bound organelles
Cell wall composed of cellulose
Contain chloroplasts
Immobile
Nutrients obtained via photosynthesis- Autotrophic
Store food as starch
State the general features of Animalia
Multicellular
Contains a nucleus and other membrane bound organelles
No cell walls
No chloroplasts
Mobile with aid of cilia, flagella or contractile proteins
Nutrients obtained by ingestion- Heterotrophic
Food stored as glycogen
What are the three domains?
Archaea
Bacteria
Eukarya
How did the Domain classification system group organisms?
Using differences in the sequences of nucleotides in the cells ribosomal RNA, cell membrane lipid structure and sensitivity to antibiotics.
What are the features of the Eukarya domain?
-Have 80s ribosomes
-RNA polymerase contains 12 proteins
What are the features of the Archaea domain?
-70s ribosomes
-RNA polymerase contains 8-10 proteins
What are the features of the Bacteria domain?
- 70 s ribosomes
-RNA polymerase contains 5 proteins
How did the five kingdoms divide into six?
The Prokaryotae group split into the Eubacteria and Archaebacteria groups.
Therefore, resulting in the six kingdoms:
Eubacteria, Archaebacteria, Protoctista, Fungi, Plantae and Animalia
What is the difference between Archaebacteria and Eubacteria?
Archaebacteria is able to live in extreme environments (eg, anaerobic conditions or thermal hot springs)
Eubacteria is known as true bacteria and is found in all environments.
What is Phylogeny?
The evolutionary relationships between organisms
What is a Phylogenetic tree?
A diagram used to represent the evolutionary relationships between organisms.
The structure shows how closely related different species are and their evolution from a common ancestor.
The closer the branches of the diagram, the closer the evolutionary relationship.
Describe how phylogenetic trees are produced
Interpreting the similarities and differences in a species physical characteristics and genetic makeup.
State the advantages of the phylogenetic classification system
-Used to confirm or change a species classification group
-A continuous tree is produced meaning organisms are not categorised into a specific group of which they don’t belong
-Equivalence between different organisms is not implied between trees
Describe the key observations that Darwin made
-More offspring are produced than can survive
-There is variation in the characteristics of members of the same species
-These characteristic can be passed on from one generation to the next
-Individuals that are best adapted to their environment are more likely to survive and reproduce
Describe Darwins theory of evolution by natural selection
Individuals within a population show variation within their phenotype
Selective pressures (environmental factors: predation, disease and competition) decrease chance of survival
Therefore, organisms that are better adapted to their environment are more likely to survive and reproduce- passing advantageous alleles to offspring
Over generations this leads to evolution as the advantageous allele becomes more frequent in the gene pool.
How did Wallace contribute to the theory of evolution?
Wallace independently proposed the idea of natural selection.
Wallace used observations which provided evidence to support the theory of evolution.
Eg, warning colours are used by species to deter consumption from predators
What sources provided evidence for evolution?
-Palaeontology (study of fossils)
-Comparative anatomy (the similarities and differences between an organisms anatomy)
-Comparative biochemistry (the similarities and differences between the chemical makeup of organisms)
How does Palaeontology provide evidence for evolution?
Supports the evolutionary theory that simple life forms gradually evolve over time to form more complex organisms.
—> bacteria present in oldest rocks
—-> vertebrates present in recent rocks
Sequence in which the organisms are identified matches their ecological links to each other.
—> plant fossils appear before animal fossils
Similarities in the anatomy of fossil organisms can show how closely related organism have evolved from a common ancestor
Relationships between extinct and living organisms can be investigated
What is a limitation to the evidence provided by palaeontology?
The fossil record is incomplete as:
-soft bodied organisms decompose quickly, rarely creating fossils
-conditions required for fossilisation are not always present
-fossils can be destroyed by geological processes
-many fossils are still yet to be discovered
What is a homologous structure?
Structure that appears superficially different (can perform different functions) in different organisms, however will have the same underlying structure.
What does the presence of homologous structures indicate?
Divergent evolution
What is divergent evolution?
The process by which different species have evolved from a common ancestor, with different adaptive features often as a result of selective pressures.