4.1 CLASSIFICATION AND EVOLUTION Flashcards
What is classification?
Classification is the process by which living things are sorted into groups. The organisms within groups share similar features.
What is phylogeny?
Phylogeny is the study of how closely related species are, looking at evolutionary relationships.
What is taxonomy?
Taxonomy is the study of the principles behind classification. Uses similarities and differences to put them into groups.
Why classify?
Why classify:
- to identify species
- to predict characteristics
- to find evolutionary links
What is the Linnaean Classification System?
Linneaean Classification:
domain
kingdom
phylum
class
order
family
genus
species
What are the 5 kingdoms?
The 5 kingdoms are fungi, protoctista, animalia, plantae, prokaryota
What is a species?
Species are the smallest unit of classification and are a group of organisms that are able to produce fertile offspring.
What is viable offspring?
Viable offspring means that the organism produced survives, but it is not capable of producing its own offspring.
Sometimes closely related species such as donkeys and horses can breed and produce offspring together. However, their offspring (a mule or hinny) is infertile. Therefore horses and donkeys are classified as a different species.
Mules and Hinnies.
Mules and Hinnies:
- infertile as their cells contain an odd number of chromosomes (63)
- meiosis and gamete production cannot occur correctly as each chromosome must pair up
- they have 63 chromosomes because horses have 32 pairs while donkeys have 31 pairs
What is the Binomial Nomenclature?
Binomial Nomenclature:
- all species have a name consisting of two parts
= first word = organisms genus (generic name)
= second word = organisms species (specific name)
- number of species have the same generic and specific name
What is autotrophic?
Autotrophic is an organism that does not require organic nutrients.
What is heterotrophic?
Heterotrophic is an organism that requires organic nutrients.
What is saprotrophic?
Saprotrophic are organisms that release extra-cellular enzymes and absorb nutrients.
What are the features of the prokaryota kingdom?
Prokaryota:
- unicellular = single cell or small groups of cells (prokaryotic)
- no membrane bound organelles
- no nucleus = ring/loop of DNA
- smaller ribosomes than eukaryotes
- peptidoglycan cell wall
- split into bacteria and amoeba
What are the features of the protoctista kingdom?
Protoctista:
- all eukaryotic, all differ (defined by exclusion) = some have cellulose cell wall, some have chloroplasts
- protozoa, algae
What are the features of the fungi kingdom?
Fungi:
- feed heterotrophically from dead things
- chitin cell wall
- unicellular or multicellular
- hyphae from mycellium
- most store food as glycogen
What are the features of the plantae kingdom?
Plantae:
- multicellular, eukaryotic
- cellulose cell wall
- feed autotrophically = feed via photosynthesis, store food as starch
What are features of the animalia kingdom?
Animalia:
- multicellular, eukaryotic
- feed heterotrophically = food stored as glycogen
- millions of species
- evolved, some disappear
- no cell wall
- membrane bound organelles
How were things classified (early)?
Early classification:
- observable characteristics = morphology, anatomy
- similarities in behaviour = e.g living or moving in water/air
What is morphology?
Morphology is the study of relationships of organisms’ structure.
What is anatomy?
Anatomy is the study of the structures and organisms themselves.
What advances in technology have happened to improve the way things are classified?
Advances in technology:
- light microscope
- electron microscope
- physiology
- biochemistry
What is physiology?
Physiology is the way in which a living organism or body part functions.
How are things classified (modern)?
Modern classification:
1. DNA
2. physiology
3. morphology
4. biochemistry
5. cytochrome C
= protein used in respiration (all organisms must have)
= amino acid sequence for the protein is different in all organisms
= the more similar it is, the more closely related the organisms
must be
What are Woese’s findings?
Woese’s findings:
- eukarya (80S ribosomes and RNA polymerase made up of 12 proteins)
- archea (80S ribosomes and RNA polymerase made up of 8-10 proteins)
- bacteria (70S ribosomes and RNA polymerase made up of 5 proteins)
- conducted these were 3 main domains
- as Woese divided prokaryotae into 2 domains (Eubacteria & Archea) this means that there would be 6 kingdoms = eubacteria, archaebacteria, protoctista, fungi, plantae, animalia).
What are the advantages of phylogenic classification?
Advantages of pylogenic classification:
- phylogeny can be done without reference to Linaean classification
- phylogeny influences classification
- phylogeny produces a continuous tree rather than discrete taxonomical groupings
- hierarchal style of classification can be misleading in evolutionary comparison, whereas phylogeny accounts for time
What is evolution?
Evolution is the theory that describes the way organisms change/evolve over many years as a result of natural selection.
What is natural selection?
Natural selection is the process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes.
What is the process of natural selection?
Process of natural selection:
1. mutation
2. variation within population
3. selection pressure
4. some survive, some die
5. reproduction to pass on allele/mutated gene
6. repeated over many generations
7. allele increases in population
What is uniformatarialism?
Uniformalarialism are natural processes that have shaped the land and have always done so (e.g sedimentation, wind erosion and deposition).
What were Darwin’s observations?
Darwin’s observations:
1. individuals within a species differ from each other- there is variation
2. offspring resemble their parents- characteristics are inherited
3. far more offspring are generally produced than survive to maturity- they suffer from predation, disease and competition
4. populations are usually fairly consistent in size
What were Darwin’s conclusions?
Darwin’s conclusions:
1. there is a struggle to survive
2. individuals better adapted to their environment have an advantage over others
3. they survive longer and reproduce more, passing on their successful characteristics to the next generation
What did Darwin and Wallace do as they had similar ideas?
As Darwin and Wallace has similar ideas, they proposed the theory of evolution through natural selection through a joint presentation of their 2 papers to the Linnaean society of London.
How is a fossil produced?
A fossil is produced when animal and plant remains are preserved in rocks.
What is the fossil record?
The fossil record suggest that organisms in different layers from oldest to youngest gradually change over time.
How old are the oldest cyanobacteria fossils?
The oldest cyanobacteria fossils are 3.5 billion years old.
What is the proof that life forms evolved over an extremely long period of time?
The proof that life forms evolved over an extremely long period of time is that simplest organisms are found in the oldest rocks and fossils of more complex organisms are found in the most recent rocks.
How can fossils prove there are ecological links between species?
Fossils can prove there are ecological links between species by the sequence in which organisms are found. E.g plant fossils found before animal fossils.
How can scientists use fossils to show how closely related organisms have evolved from the same ancestors?
Scientists can use fossils to show how closely related organisms have evolved from the same ancestors by studying the anatomy. E.g skull and skeleton.
What are strata?
Strata are a layer/series of layers of rock in the ground.
