Module 4 - Chapter 10 - Classification And Evolution Flashcards
Define binomial system
Universal naming system taken from an organism’s “genus, species” eg. Homeo-sapien
What is the taxonomic hierarchy (7)
Kingdom
Phylum
Class
Order
Family
Genus
Species
What did Carl Linnaeus propose?
Came up with the 7 taxonomical hierarchy system
Arranged organisms into ‘taxa’
Used binomial nomenclature
What did Carl Woese do?
Came up with the 3 domain system above the Linnaean system
Eukaryotae, prokaryotae and archaea
Define autotrophic - what organisms are autotrophic?
Feed themselves - produce their own food
E.g. plants photosynthesise
Define heterotrophic - what organisms are heterotrophic?
Get food by eating other organisms
E.g. humans eat meat from animals and plants
Define saprotrophic - what organisms are saprotrophic?
Absorbs substances by excreting enzymes and digesting dead organisms
Fungi are saprotrophic
What is a chaemotroph
An organism that uses chemicals instead of sunlight to synthesise food
Define chortada
Vertebrates
What are the 5 kingdoms
Prokaryotae, protoctista, fungi, plantae, animalia
What are analogous traits
Similar characteristics that occur because of environmental constraints, not due to close evolutionary relationships
Why is it difficult to classify organisms such as fungi
Because they have similar features to plants - immobile and hyphae that act as roots, but do not photosynthesise and are heterotrophic like animals / saprotrophic
Why did microscopes improve classification
When improved microscopes studied organisms, they were able to see sun-cellular structures and use chemical/ biological features to classify organisms instead of visible characteristics
Why is the binomial nomenclature useful?
Because Latin is universal so every scientist in the country will use the same name - avoids confusion
Define morphology
The observable/ visible features of an organism
What is artificial classification
Classification based off of morphology - physical, visible features.
What is a homologous trait
When organisms share a trait due to common ancestry
What are some features of prokaryotae
No nucleus, DNA orgnaised in circular DNA (plasmids) and nucleoids
Peptidoglycan cell wall
No membrane bound organelles
What features define protoctista
Many are mobile/ have flagella
Nearly all are autotrophs
Many are aquatic
Describe fungi
All are saprotrophic (and heterotrophic)
Chitin cell wall - amino polysaccharide
Non-vascular
What are the features of plantae
Cellulose cell walls, many are photosynthetic
Plants are multicellular
What defines animalia
Sexual reproduction
Advanced nervous system
During development, multicellular embryo is formed from the zygote
Vascular system and excretory system
Define species
A group of organisms that can breed together to produce fertile offspring
Define species
A group of organisms that can breed together to produce viable/ fertile offspring
What are the 5 categories that organisms of the same species are similar in
Appearance
Anatomy
Physiology
Biochemistry
Genetics
Define pseudopodia
Temporary protrusion if the surface of an amoeboid cell for movement and feeding
Define convergent evolution
When two unrelated species adapt in a similar way, therefore look similar
Why does convergent evolution make observational classification hard?
Because completely unrelated species will look similar so people might classify them wrongly in the same group
Why is it essential to use molecules such as DNA or Cytochrome C when classifying
Because all living organisms that respire must have cytochrome C but it’s different in all species. If the sequences are the same the species are closely related
Why are molecules such as starch and amylase not used for classification
Because they have no sequence and amylase shows insufficient differences and isn’t ubiquitous - active site always stays the same
Humans don’t have the enzyme to break down starch (cellulase)
Why did woese feel that the differences in RNA polymerase were so important?
Because he felt the differences between bacteria and archaea are more fundamental than archaea and eukaryotae therefore producing the 3 domain system
Define phylogeny
The study of evolutionary relationships between species
What are the factors of artificial classification
Done for concenience, easier to remember
Based only on a few characteristics
Does not reflect any evolutionary relationships
Provides limited information
Is stable
What are the factors of natural classification
Uses many characteristics
Reflects evolutionary relationships
Detailed study of the individuals in a species
Provides a lot of useful information
May change with advancing knowledge
What are the advantages of phylogeny
Can be done without reference to the Linnaean system
Produces a continuous tree whereas classification requires distinct/ discrete taxonomical groups
The hierarchal nature of Linnaean system may be misleading - implies different groups with the same rank are equivalent and doesn’t show how long the species has been present for
What are the 3 main sources of evidence for evolution
Palaeontology
Comparative anatomy
Comparative biochemistry
How are fossils formed?
When animal and plant remains are preserved in rocks. sediment is deposited on watch to form layers, strata, which correspond to different geological areas
Define fossil record
The ability to see the change in organisms gradually overtime
What evidence has been gathered from the fossil record
Simple organisms found in older rocks and more complex organisms found in newer rocks - supports the theory that all organisms started off simple and evolved to become more complex
The sequence in which the organisms are found matches their ecological links to each other
Scientists can use anatomy to show how closely the organisms were related that evolved from a common ancestor
Allows relationships between extinct and extant (living) organisms to be investigated
What are some cons of the fossil record
Not complete
Many organisms are soft-bodies and decompose before fossilisation
Conditions needed for fossils to form are not always present
Fossils destroyed by earths movements eg. Volcanoes
what are some key facts about Darwin?
5 year trip on the HMS beagle - visited Galapagos islands - discovered unusual species
carried out observations on FINCHES - noticed variation between different islands - according to the food available on each island
1859 - published “the origin of species”
what did Alfred Wallace do?
developed his own theory of natural selection which was published at the same time as Darwin
the two discussed their similarities but their ideas were developed independently
Wallace studied butterflies instead of finches
presented, joint with Darwin, to the Linnaean Society of London 1858
why did Darwin’s theory split the scientific community?
Darwin’s theory conflicted the widely held Christian belief that “God created man”
the debate with religious groups continues today
what are the characteristics of placental mammals
have a long gestation (pregnancy)
develop a placenta in pregnancy (for exchange of nutrients and waste)
young are born very well developed then receive milk
what are the characteristics of marsupial mammals
found in Australia and the Americas
have a short gestation (pregnancy)
don’t develop a full placenta
born early
climb into their mother’s pouch to receive milk from a teat
what evidence do we have for evolution
fossils
differences in DNA and RNA base sequences
molecular evidence - differences in biochemistry
current evolution - antibiotic/ pesticide resistance
what did Darwin conclude from his studies
- there is a struggle for survival
- better adapted individuals survive and pass on their successful characteristics
- over time, the number of changes may give rise to a new species
NB - no knowledge of chromosomes or DNA at this time
describe the sequence of natural selection
- there is genetic variation within the population (mutations)
- a selection pressure creates competition for survival
- some individuals possess favourable alleles/ characteristics which means they are better adapted to the environment
- the individuals with the favourable alleles survive and reproduce
- repeated over many generations so the percentage of favourable alleles in the population increases
what are some examples of selection pressures
antibiotics - for antibiotic resistance in bacteria
pesticides - for pesticide resistance in pets
availability/ type of food - Darwin’s finches
predators - camouflage/ behaviour
disease - disease resistance / survival
physical and chemical factors - light, temp, water availability
what are the genetic causes of variation
- alleles - different alleles produce different effects - may inherit different alleles of a gene
- mutations - changes to the DNA sequence leads to changes in the proteins the genes code for
- meiosis - gametes undergo independent assortment of chromosomes and crossing over
- sexual reproduction - offspring produced from 2 parents inherit characteristics from both parents
- chance - many different gametes are produced from the parental genome - individuals differ from siblings etc.
What are neutral changes
Changes that do not effect a molecule’s function - occur at a regular weight
What is divergent evolution
Describes how different species have evolved from a common ancestors, each with a different set of adaptive features
What is comparative biochemistry
Study of proteins and other biological molecules that control life processes
Some important molecules are highly conserved among species
Slight changes help identify evolutionary links
Cytochrome C - protein in respiration
Ribosomal RNA
Why is the 3 domain system used in preference to the 5 kingdom system?
- 3 domains fit phylogeny better
- There are many fundamental differences between bacteria and eukaryotes (other 4 kingdoms)
- there are many similarities between the four eukaryotic kingdoms
- There are many differences between bacteria and archaea
