10 - Classification And Evolution 🐵 Flashcards
What is classification?
the name given to the process by which living organisms are sorted into groups
What is taxonomy?
the study of the principles behind the classification of organisms, according to their observable features or genetic characteristics
What is phylogeny?
the study of how closely different species are related and involves the study of the evolutionary relationships between organisms seen in an evolutionary tree
Which is the biggest and broadest taxonomic group?
Kingdoms
What is the order of the hierarchy?
Kingdom
Phylum
Class
Order
Family
Genus
Species
Why do scientists classify organisms?
- to identify species
- to predict characteristics
- to find evolutionary links
Why is it good to have a single classification system?
Scientists globally can share their work and links between different organisms can be seen
What are the 3 domains?
Archaea, Bacteria and Eukarya
Define a species
A group of organisms that are able to reproduce fertile offspring
Why are mules infertile?
Their cells contain an odd number of chromosomes (63), meaning meiosis and gamete production can’t take place correctly as all chromosomes pair up
What is the classification of humans?
Homo sapiens
What are ‘common names’?
Old classification system based on physical characteristics
Why was ‘common names’ classification useless?
- organisms may have +1 common names
- different names in different languages
- doesn’t provide info on relationships
Who created the binomial nomenclature?
Carl Linnaeus
What are the 5 kingdoms?
Prokaryotae
Protoctista
Fungi
Plantae
Animalia
Features of Animalia kingdom
- multicellular
- DNA in nucleus
- membrane-bound
- no cell walls
- heterotrophic feeders
- food stored as glycogen
Features of Plantae kingdom
- multicellular
- DNA in nucleus
- membrane-bound
- cell wall of cellulose
- autotrophic feeders
- most are immobile
Features of Fungi kingdom
- uni/multicellular
- DNA in nucleus
- membrane-bound
- no chloroplasts
- cell wall of chitin
- saprophytic feeders
- food stored as glycogen
- no mechanism for movement
Features of Prokaryote Kingdom
- unicellular
- a ring of ‘naked’ DNA
- no nucleus
- not membrane-bound
- cell wall of peptidoglycan
- nutrients absorbed through cell wall
- move with aid of flagella
Features of Protoctista kingdom
- mainly unicellular
- DNA in nucleus
- membrane-bound
- cell wall sometimes present
- autotrophic and heterotrophic
- some are immobile, others move by flagella
Why does DNA change as organism’s evolve?
DNA determines the proteins that are made, which in then determines an organism’s characteriatics
What is an example of a protein that has changed its structure over evolution?
Haemoglobin differs from humans in chimpanzees by only 1 amino acid, and in gorillas by 3 amino acids
What is the domain system groupings based on?
- differences in the sequences of nucleotides in the cells’ ribosomal RNA
- cells’ membrane lipid structure
- their sensitivity to antibiotics
Features of Eukarya
- 80S ribosomes
- RNA polymerase contains 12 proteins
Features of Archaea
- 70S ribosomes
- RNA polymerase contains between 8 and 10 proteins
Features of Bacteria
- 70S ribosomes
- RNA polymerase contains 5 proteins
What are archaebacteria?
- ancient bacteria
- can live in extreme environments
Why do we have both eubacteria and archaebacteria?
Archaebacteria have been found to be different chemically from eubacteria
What is phylogeny?
The study of the evolutionary relationships between organisms seen in an evolutionary tree
What does a phylogenetic tree show that Linnaean classification doesn’t?
How closely related organism are in their evolutionary relationships
What is the root of a phylogenetic tree?
The initial common ancestor
What does each node represent in a phylogenetic tree?
A common ancestor that speculated to give rise to two or more daughter taxa
What is an outgroup on a phylogenetic tree?
Most distantly related species which functions as a point of comparison
What is a clade in phylogenetic tree?
A common ancestor and all of its descendants (a node and all it’s connected branches)
Can phylogeny be done without reference to Linnaean classification?
Yes
Pros to phylogeny
How does classification use phylogeny?
Uses knowledge of phylogeny to confirm the classification groups are correct or causes them to change
Pros to phylogeny
How are phylogeny trees helpful?
The continuous tree is better than classification’s discrete taxonomical groups that not all organisms fit
Pros to phylogeny
How is phylogeny less misleading than Linnaean classification?
Linnaean implies different groups within the same rank are equivalent, even if they are not comparable
Suggest two ways in which the scientific community are likely to have validated Woese’s work
- reproduce it
- more supporting evidence
- scientific meetings
- peer review
What is evolution?
The change in heritable traits of organisms over successive generations
What 4 observations did Darwin make about the world around him?
- organisms produce more offspring than survive
- there’s variation in the characteristics of members of the same species
- some of these characteristics can be passed on
- individuals best adapted to environment survive
Why do organisms produce more offspring than survive?
- due to selection pressures
- survival of the fittest
Why is there variation in the characteristics of the same species?
- favourable characteristics
- survival of the fittest
Why are characteristics passed in from one generation to the next?
- increase allele frequency of those favourable characteristics
Suggest how information from DNA analysis can be useful to taxonomists?
- can compare DNA
- can compare proportions of bases
What evidence is there for evolution?
- palaeontology
- comparative anatomy
- comparative biochemistry
- embryology
- species distribution
What are the principles of natural selection?
- Overpopulation = competition
- Variation is due to mutation
- Selection via adaptation (S.otF)
- Adaptation breed and pass on characteristics
What does it mean if factors are density dependent?
Size of the population affects it
What does it mean if factors are density independent?
Size of the population doesn’t affect it
What are density dependent factors impacting selection pressure?
Predators
Available food/shelter
Nutrient supply
Disease
Accumulation of waste
What are density independent factors impacting selection pressure?
Phenomena (natural disasters)
Abiotic factors (temp, CO2 levels)
Weather conditions
Comparative Anatomy
What are homologous structures?
The underlying structures are similar, but the function may be different
Comparative Anatomy
Give an example of a homologous structure
Pentadactyl limb
Comparative Anatomy
What does the presence of homologous structure provide evidence for?
Divergent evolution
What is divergent evolution?
This describes how, from a common ancestor, different species have evolved with different adaptive features
When will divergent evolution occur?
When closely related species diversify to adapt to new habitats due to migration or loss of habitat
Palaeontology
Give reasons why the fossil record isn’t complete
- not all found
- some organisms decompose before they have chance to fossilise
Palaeontology
How do fossils form?
When an animal or plant remains are preserved in rocks
Palaeontology
What is rock strata?
Layers of rock
Palaeontology
What do different layers of rock correspond to?
Different geological eras
Palaeontology
What does the deeper the rock mean?
Older fossils
Palaeontology
How can we determine the age of a fossil?
Radioactive carbon dating
Comparative Biochemistry
What is comparative biology the study of?
Similarities and differences in the proteins and other molecules that control life provesses
Comparative Biochemistry
What are 2 of the most common molecules studied?
Cytochrome C and rRNA
Comparative Biochemistry
What 2 types of DNA can be analysed?
Nuclear and mitochondrial
Comparative Biochemistry
What does changes in non-functional groups result in?
Neutral evolution due to no effect on function
Comparative Biochemistry
Explain how biological molecules can provide evidence species have evolved
- antibodies
- DNA packing around Haiti es
- RNA
- amino acid sequences
What is interspecific variation?
Variation between different species
What is intraspecific variation?
Variation between the same species
What 2 factors cause variation?
- an organism’s genetic material
- the environment in which the organism lives
What are the 5 genetic causes of variance?
- alleles
- mutations
- meiosis
- sexual reproduction
- chanve
Why may plants be affected greater by their environment than animals?
Due to their lack of mobility
What is an example of a characteristic that is determined purely by environmental variation?
The presence of absence of scares on your body - scars can’t be inherited from a parent
In most cases, what causes variation?
Both genetic and environmental factors
Give an example of a characteristic that shows both environmental and genetic causes
Skin colour
- determined by how much melanin pigment it contains
- exposure to sunlight changes colour
What is discontinuous variation?
A characteristic that can only result in certain values
Variation determined purely by what falls into discontinuous variation?
genetic factors
What graph represents discontinuous variation?
Bar chart
What is continuous variation?
A characteristic that can take any value within a range
Characteristics that show continuous variation are controlled by what?
Multiple genes and environmental factors, not just a single gene
What chart is used to represent continuous variation?
A histogram
What are characteristics of normal distribution?
- mean/mode/median are the same
- bell shape graph
- 50% of data is less than mean and 50% is more
- most values lie close to mean
What is the shape of a normal distribution curve?
Bell shaped
What does standard deviation measure?
How spread out the data is
What does students t-test show?
This is used to compare the means of data values of two populations
What does spearman’s rank correlation coefficient show?
This is used to consider the relationship of between two sets of data
What can data show?
- no correlation
- positive or negative correlation
What are adaptations?
Characteristics that increase an organism’s chance of survival
Adaptations can be divided into what 3 categories?
- anatomical = physical features
- behavioural = actions
- physiological adaptations = processes
Anatomical adaptations
What is body covering?
- animals have a number of different body coverings such as hair, scales, spines, feathers etc
Anatomical adaptations
List 3 anatomical adaptations
- camouflage
- teeth
- mimicry
Anatomical adaptations
How is Marram grass adapted anatomically to reduce the rate of transpiration?
- curled leaves
- hairs on inside of leaves to trap moisture
- stomata in sunken pits
- thick waxy cuticle
Behavioural adaptations
Give an example of survival behaviour
An opossum plays dead and a rabbit freezes when they think they’ve been seen
Behavioural adaptations
Give an example of seasonal behaviours
- migration
- hibernation
Behavioural adaptations
How is courtship an adaptation?
Many animals exhibit elaborate behaviours to attract a mate
Behavioural adaptations
What two categories do behavioural adaptations fall into?
- innate (instinctive) behaviour
- learned behaviour
Behavioural adaptations
What is innate behaviour?
The ability to do this is inherited through genes, allowing an organism to survive in the habitat it lives in
Behavioural adaptations
What is learned behaviour?
Adaptations learnt from experience or observing other animals
Physiological adaptations
How is poison production an example?
Many reptiles produce venom to kill their pray
Physiological adaptations
List 3 examples
- poison production
- antibiotic production
- water holding
What are analogous structures?
They have adapted to perform the same function but have a different genetic origin
Give an example of analogous structures
Tail fins of wake and fish
What is convergent evolution?
When unrelated species begin to share similar traits, due to similar environments/selection pressures
Give an example of convergent evolution
Marsupials in Australia and placental mammals in the Americas
In placental mammals, what happens?
A placenta connects the embryo to its motjer
In marsupials, what happens?
Leave the uterus and enter the marsupium (pouch) while they are still embryos and suckle milk here
Give examples of convergent evolution
- marsupial and placental micr
- marsupial and placental moles
How has a new strain of flavobacterium shows natural selection can be helpful?
A new strain of flavobacterium is waste water from factories that produce nylon 6. This strain of bacteria has evolved to digest nylon and is beneficial for cleaning up factory waste
What are the steps of natural selection?
- organisms show variation
- organisms better adapted survive
- successful organisms pass on allele
- repeated over generations
- leads to evolution of new species
What selection pressure caused changes in peppered moths?
The Industrial Revolution smog and dirt
Why did dark peppered moths become better adapted to their environment?
They were more camouflaged on the darker stained trees than pale moths
What happened to the population of pale peppered moths?
Decreased as no longer had a selection advantage
Where do sheep blowflies lay their eggs?
In faecal matter around a sheep’s tail - the larvae then hatch and cause sores
Why can sheep blowflies no longer be killed with antibiotics?
Developed high level of resistance within 6 years
What have scientists studied to see why sheep blowflies had resistance so fast?
DNA of 70 year old species of fly and modern species
Where did scientists find resistance when they looked at sheep blowflies DNA?
Resistant alleles were found in both, showing there was pre-existing resistance to the antibiotic
