4.2.2 Classification and evoloution Flashcards
Define classification.
The process of naming and organising organisms into groups based on their characteristics.
Define taxonomy.
Classifying organisms
Name the 8 groups an organism can be classified into from biggest to smallest.
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What are the 5 kingdoms of classification?
Prokaryota
Protoctista
Fungi
Plantae
Animalia
How do bacteria divide?
Binary fission
What is the component of bacterial cell walls?
peptidoglycan
What type of ribsomes do bacteria possess?
70S
What is classified into the prokaryota kingdom?
Bacteria
Features of prokaryota kingdom.
-Most unicellular
-Divide by binary fission
-Have cell walls but no nucleus or mitochondria.
What are classified into the protocista kingdom?
All eukaryotic cells which do not belong in the other three eukaryotic kingdoms.
Features of protocistia kingdom.
-Vary in all aspects such as structure, life cycle, feeding etc.
-No cell wall
Features of the fungi kingdom?
-Eukaryotic cells.
-no cell walls
-No cillia
-Reproduce using spores
-Long hyphae
Features of plantae kingdom?
-Cell walls composed of cellulose
-sometimes have flagella
-Possess chloroplasts
-Can differentiate into specialised cells to form tissues and organisms.
Features of Animalia kingdom.
-Multicellular organisms
-No cell walls
-Heterotrophs
-Can differentiate into specialised cells.
What are the three domains in classification?
Bacteria
Archea
Eukarya
Features of eukarya domain
-vary massively in size
-divide by mitosis
-can reproduce sexually or asexually
features of archea domain
-no nucleus
-similar size range to bacteria
-no peptidoglycan
-ribosomal structure more similar to the eukaryotic ribosomes
What did charles darwin observe?
-All organisms produce more offspring than could ever actually survive.
-Populations of organisms do fluctuate.
-Populations of the same specifies show variation in characteristics between individuals.
-Offspring inherit characteristics from their parents.
Who invented the binomal naming system?
Carl linnaeus
What is a species
A group of organisms that are able to reproduce and produce fertile offpsring.
Two components of a binomal name.
The genus
The species
Why are binomal names useful to scientists?
It is universal so species can be identified all around the world.
What is phylogeny?
Investigates the evolutionary relationship between organisms
How does fossil evidence act as evidence for evolution?
We can tell from fossils that organisms have changed significantly over millions of years.
Fossils can be dated allowing us to put fossil organisms into a sequence from oldest to youngest.
Fossils allow us to see similarities between extinct species and present day species.
What are fossils?
Preserved remains of organisms or things left behind by organisms
How is molecular evidence evidence for evolution?
DNA found in the nucleus of cells can be sequenced and used to provide evidence of evolutionary relationships between species and how their genetic code has changed as they have evolved.
How do phylogenetic trees help?
They help to show the evolutionary relationship between different taxa.
Define variation.
Differences that exist between two or more things.
Differentiate between interspecific and intraspecific variation.
Interspecific- Variation between species
Intraspecific- Variation within species
Differentiate between continuous and discontinuous variation.
Discontinuous- Qualitative differences within a population that can be categorised with no intermediates.
Continuous- Quantitative differences that do not fall into categories.
Example of discontinuous variation.
Blood group
Example of continuous variation.
Height or mass of an organism
Causes of discontinuous variation.
Genetic factors. Environment has no effect.
Causes of continuous variation.
Interaction between genetic and environmental factors.
What is a selection pressure?
Environmental factors that affect the chance of survival in an organism.
What are adaptations?
When an organism has allele(s) which makes it better suited to be able to survive and reproduce more easily.
What are the three types of adaptations?
-Anatomical adaptations
-Physiological adaptions
-Behavioural adaptations
What are anatomical adaptations?
Structural or physical features.
Example of anatomical adaptation.
Polar bears white fur provides camouflage in snow.
What is a physiological adaptation?
Biological processes within the organism.
Example of physiological adaptation.
Mosquitos produce chemicals that stop animals blood clotting when they bite so they can feed more easily.
What are behavioural adaptations.
They way an organism behaves.
Example of behavioural adaptation.
Cold blooded reptiles bask in sun to absorb heat.
What is convergent evolution?
When species have evolved in two very different habitats they have become adapted to those habitats.
What is genetic variation?
When two individuals of the same species have differences between their DNA base sequences
Is a small or large gene pool beneficial?
A population with a large gene pool has a strong ability to adapt to change however one with a small gene pool are much less able to adapt to chance and risk extinction.
How can we use DNA sequencing for phylogeny and classification?
Sequencing technology can determine the order of DNA or mRNA bases and amino acids within an organisms genome and this can be beneficial when comparing extinct species DNA with a species that is physically similar.
Why is cytochrome C used in DNA sequencing?
It is an essential protein to respiration which is used by all eukaryotic organisms.
The amino acid sequence of cytochrome C varies in different species so can be used to see how closely related organisms are.
Species that are not as closely related will have had a greater amount of time to accumulate mutations and changes to their DNA, mRNA and amino acid sequences.
How can we use DNA analysis for phylogeny and classification?
DNA is extracted from the nuclei of cells taken from an organism and is processed to obtain the base sequence.
The base sequence is compared to that of other organisms to determine evolutionary relationships.
The more similar the base sequence is, the more closely related the organisms are.
How can we use antibodies for phylogeny and classification?
Pure albumin samples are extracted from blood samples taken from multiple species.
Each pure albumin is injected into a different rabbit.
Each rabbit produces antibodies for that specific type of albumen.
The different antibodies are extracted from the different rabbits and then mixed with the different albumin samples.
The precipitate resulting from each sample is weighed.
The greater the weight of the precipitate, the greater the degree of similarity between the antibody and the albumin.
Why do we use the protein albumin for using antibodies for phylogeny and classification?
It is found in many species.
How can use DNA hybridisation for phylogeny and classification?
1) Heat seperate DNA strands from two organisms.
2) Combine the two strands of DNA
3) Cool to allow renaturation of double strands.
4) Determine the degree of hybridisation.
If there is complete hybridisation then the organisms are identical.
No hybridisation= organisms unrelated.
