C10- Classification and Evolution Flashcards
Species definition
A group of organisms that are capable of interbreeding and producing fertile offspring.
Why classify organisms
To establish evolutionary links
Identify (new) species
Sharing research across the world (using the same ‘language’)
Linnaen system- descirbe
Carl Linnaeus grouped organisms together, based on their observable structure and characteristics.
Linnean system- names of categories
Kingdom
Phylum
Class
Order
Family
Genus
Species
What happens as you descend the levels of classification
The organisms at that level have more in common so the groups get smaller.
They are more closely related.
Binomial nomenclature
(Binomial naming)
Genus species
By convention the Genus (first part of the name) has a capital letter.
The name is written either in italics or underlined.
e.g. Homo sapien
Autotrophic
define
organisms get their nutrition from photosynthesis
Heterotrophic
define
Organisms get their nutrition from ingesting other organisms
Saprotrophic / saprophytic
define
Organisms that get their nutrition by extracellular digestion and absorption of soluble molecules (usually from decaying organic matter)
5 kingdoms
name
Prokaryotae (bacteria)
Protoctista (unicellular eukaryotes)
Fungi (yeasts, moulds, mushrooms)
Plantae (plants)
Animalia (animals)
Who proposed the 5 kingdom system
Proposed by Robert Whittaker in 1969
How to classify organisms into the 5 kingdom system
observable characteristics
Unicellular or multicellular (or both?)
The nature of their genetic material
Ability to move
How they obtain nutrients
Motility
Define
the ability to contract muscles to enable movement
Prokaryotes
Characteristics
unicellular
no membrane-bound nucleus
loop of naked circular DNA (no histones)
no chromosomes
no membrane bound organelles
the cell wall of bacteria contains peptidoglycan, composed of sugars and amino acids. Archaea cell walls do not contain this.
Smaller ribosomes (70s)
Reproduce mainly by binary fission (splitting in half), but some can reproduce sexually.
3 most common shapes of prokaryotes
Helix
Sphere
Rod
Protoctista
7
kingdom
sometimes called protists.
eukaryotic and unicellular
commonly found in water.
organisms show characteristics of both plants and animals.
Include the algae, seaweeds, amoeba, plasmodium (malaria parasite).
Some are autotrophic and some have heterotrophic nutrition.
They are mobile due to either flagella, cilia, or pseudopods (“false feet”).
Plantae
7
kingdom
Eukaryotic
Multicellular
Cells surrounded by a cellulose cell wall.
Large vacuole in mature cells.
Store energy as starch
Have chlorophyll and chloroplasts.
Mostly autotrophic by photosynthesis.
Fungi
12
kingdom
Eukaryotic (nucleus and membrane-bound organelles)
No chlorophyll – do not photosynthesise
Single celled (yeasts) and multicellular (filamentous - macroscopic)
Body is a mycelium that consists of hyphae.
Cell walls made of chitin
Cytoplasm multinucleate in the filamentous fungi.
Mostly free-living and saprophytic.
Extra-cellular digestion - secreting enzymes onto organic matter and absorbing soluble products.
Reproduce asexually by release of spores.
Also able to reproduce sexually as well if needed
Store glycogen as an energy source
Animalia
6
kingdom
Eukaryotic
Multicellular
Heterotrophic nutrition
Have muscles and nervous systems – in order to search for, locate and digest food.
Most have a gut.
Glycogen is stored energy source
Evidence for evolution
Palaeontology- study of the fossil record
Comparative anatomy- the study of similarities and differences between organisms anatomy
Comparative biochemistry- similarities and differences between the chemical makeup of organisms
Who developed the theory of evolution
Charles Darwin and Robert Whittaker
Theory of evolution
The way in which organisms evolve over many years a sa result of natural selection
Darwin’s conclusions on evolution
Survival of the fittest
Organisms best suited to their environment are more likely to survive and reproduce, passing on their characteristics to their offspring
Gradually a species changes over time to have the advantageous phenotype for the environment in which it lives
Evidence for evolution
Paleontology
Fossil analysis
Layers of rock separate geological eras
Fossils of simplest organisms are found furthest back, supporting the theory life gradually evolved towards complexity
