Module 4.2.2 - Classification and evolution Flashcards
Why do biologists classify organisms?
To identify organisms easily and to scientifically organize knowledge
Why is it important to give organisms scientific names?
Only has 1 unique name to avoid confusion
What does biological classification mean?
Organization of living and extinct organisms into systematic groups based on similarities/differences between species
Why must every species be studied in detail before being correctly placed in a group of similar organisms?
- convenience
- identify species
- predict characteristics
- find evolutionary links
What is taxonomy?
The study and practice of naming and classifying species and groups of species within the hierarchical classification scheme
Name the taxonomy
Domain, kingdom, phylum, class, order, family, genus, species
What is the binomial system?
A system of naming species in which each species has 2 names : a generic name and a specific description
What were the issues with grouping organisms based on similar characteristics before classification systems were used?
- same organisms may have a completely different common name in different parts of 1 country or other countries
- translation of languages/dialects may give different names
- same common name could be used for a different species in another part of the world
Name the 5 kingdoms
Prokaryote
Protist
Fungi
Plantae
Animalia
Describe prokaryotes
- mostly unicellular
- have no nucleus
- have a loop of DNA that’s not arranged in a linear chromosome autotrophic and heterotrophic
- no membrane bound organelles
- have smaller ribosomes than in other groups (70s)
- cells smaller than eukaryotes
- can be free living or parasitic
What did early classification rely on?
Observable features only to place organisms into groups such as appearance and anatomy
Describe protists
- eukaryotic
- mostly single celled (many algae are multicellular)
- have wide variety of forms
- show various plant like and animal like features
- mostly free living
- have autotrophic or heterotrophic nutrition
Describe fungi
- eukaryotic
- can exist as single cells (yeasts) or have a mycelium that consists of hyphae
- cell walls made of chitin
- cytoplasm is multinucleate
- mostly free living and saprophytic (cause decay of organic matter)
Describe plantae
- eukaryotic
- multicellular
- cell walls made of cellulose
- contain chlorophyll
- autotrophic
Describe animalia
- eukaryotic
- multicellular
- heterotrophic
- usually motile
What are examples of prokaryotes?
Bacteria, cyanobacteria
What are examples of protists?
Unicellular eukaryotes, algae, protozoa
What are examples of fungi?
Yeasts, molds, mushrooms
What are examples of plantae?
Mosses, ferns, flowering plants
What does autotrophic mean?
Absorb simple molecules and build into larger molecules
What are examples of animalia?
Mammals, birds, reptiles, fish, insects, mollusks, nematodes
What does heterotrophic mean?
Digest larger molecules to form smaller molecules for absorption
What is artificial classification?
- done for convenience
- only based on a few characteristics
- doesn’t reflect evolutionary relationships
- stable
- provides limited amount of info
What is natural classification?
- involves a more detailed study of individuals in a species
- uses many characteristics
- reflects evolutionary relationships
- based on homology
- provides a lot of useful info
- may change with advancing knowledge
What is homology?
The existence of shared features that are inherited from a common ancestor. The shared featured may not be used for the same thing.
E.g. pentadactyl limb
What does phylogeny mean?
The study of evolutionary relationships between organisms
What are the benefits of phylogeny?
- can be done without referring to the Linnaean classification
- provides a continuous tree whereas classification requires discrete taxonomical groups
- not as misleading as hierarchical classification of the Linnaean system
What is the biological species concept?
The ability of 2 individuals to successfully produce viable, fertile offspring
What is the phylogenetic species concept?
How closely related individuals are evolutionarily, the concept of a species as an irreducible group whose members are descended from a common ancestor and who all possess a combination of certain defining or derived traits
What is the morphological species concept?
Whether individuals look similar
What is the ecological species concept?
Whether the individuals use or can use the same set of biological resources
What does GENIE stand for in evidence of evolution?
G - genetic variation
E - environment
N - natural selection
I - inheritance
E - evolution
What were Darwin’s contributions to evidence of evolution?
- Proposed the mechanism of natural selection for the theory of evolution
- his ideas were developed during observations he made in Galapagos Islands
What were Darwin’s 4 main observations?
- offspring generally appear similar to their parents
- no 2 individuals were identical
- organisms have ability to produce large numbers of offspring
- populations in nature tend to remain fairly stable size
What were Wallace’s contributions to evidence of evolution?
- developed theory of natural selection independently to Darwin
- collected evidence and many many observations in parts of the world
What were Wallace’s 3 main observations?
- some organisms had advantageous adaptations evolved by natural selection
- geographical boundaries often marked species boundaries
- most individuals found in habitats were best fitted for that environment