4.2.2 Classification and evolution Flashcards
order of taxonomic groups
domain/kingdom phylum class order family genus species
why classify organisms
identify species
predict characteristics (members of same group highly likely to have same characteristics)
find evolutionary ancestor links
classification definition
process of placing living things into groups
binomial nomenclature definition
system that uses genus and species names to avoid confusion when naming organisms
species definition
group where all members can reproduce to produce fertile offspring
are essentially the same genetically but may show some variations
how organisms classified
based on features (anatomy) and evolutionary relationships
larger taxonomic groups to smaller taxonomic groups
different organisms in smaller taxonomic groups share more of same characteristics
why binomial nomenclature is used
organisms may have multiple common name
different names in different languages
directly states information about relationships between organisms
5 kingdoms
Prokaryotae Protoctista Fungi Plantae Animalia
Prokaryotae kingdom general features
unicellular
no membrane-bound organelles
no nucleus
have looped DNA not arranged in chromosome
DNA not bound to histone proteins (naked)
smaller ribosomes (70S)
free-living or parasitic
Protoctista kingdom general features
eukaryotic
mostly single-celled (some algae multicellular)
show various plant-like or animal-like features
mostly free-living
autotrophic or heterotrophic nutrition
autotrophic definition
absorb nutrients and build them into larger organic molecules
heterotrophic definition
digest larger organic molecules to form smaller organic molecules for absorption
saprophytic definition
digest organic molecules outside of organism then absorbs it
cause decay of organic matter
Fungi kingdom general features
eukaryotic single-celled (yeasts) or have mycelium consisting of hyphae walls made of chitin multinucleate cytoplasm mostly free-living saprophytic
Plantae kingdom general features
eukaryotic multicellular cells surrounded by cellulose cell wall autotrophic contain chlorophyll
Animalia kingdom general features
eukaryotic
multicellular
heterotrophic
usually able to move around
recent changes to classification systems
before just based on observable features
study of genetics and other biological molecules (DNA, haemoglobin, cytochrome C)
can study evolutionary relationships between organisms to classify organisms
differences between archaea and bacteria
different cell membrane structure
different internal structure of flagella
different enzyme for synthesising RNA
no proteins bound to genetic material (Archaeae do)
different mechanisms for DNA replication and synthesising RNA
archaea and eukaryotes similarities
similar enzymes and mechanisms for synthesising RNA
similar mechanisms for DNA replication replication
production of some proteins that bind to DNA
artificial classification definition
based on only few characteristics
doesn’t reflect any evolutionary relationships
provides limited information
stable
natural classification definition
uses many characteristics
reflects evolutionary relationships
provides lots of information
may change with advancing knowledge
phylogeny definition
study of evolutionary relationships between species
natural selection method
variation (organisms of species have different adaptations to each other due to mutation)
better adapted individuals can compete better, survive sudden changes in to environment (selection pressure)
more likely to pass on their advantageous characteristics to next generation by reproduction
evidence for evolution
new species and fossils of old species look similar (new species better adaptations)
compare structure of biological molecules e.g. DNA, cytochrome C, amino acid sequence of proteins (if one species gave rise to another, biological molecules likely to be similar, more similar = more closely related)
continuous variation definition
variation where two extremes and a full range of values in between
use histogram
discontinuous variation definition
where there are distinct categories and nothing in between
use bar chart
environmental variation definition
variation caused by response to environmental factors such as light intensity
genetic variation definition
variation caused by possessing different combinations of alleles
intraspecific variation definition
variation between members of same species
interspecific variation definition
differences between species
variation definition
presence of variety
differences between individuals
combined effects definition
both environmental and genetic variation affect certain characteristics e.g. height, weight
adaptation definition
characteristic that enhances survival in habitat
anatomical adaptation definition
structural features modified to enhance survival
behavioural adaptation definition
ways behaviours is modified for survival
physiological adaptation definition
modified the way biochemical processes work in the organism
convergent evolution definition
when 2 separate, unrelated species evolve to have similar characteristics
standard deviation formula
s = square root of: sum(x-mean)^2 / (n - 1)
standard deviation use
measure of variation (amount of variation from mean)
low = data more closely grouped = greater reliability of data
high = data more spread apart = less reliability
Student’s t-test use
compares two means
test whether difference between 2 means is statistically significant
Student’s t-test
t = (mean1 - mean2) / (square root of (s1^2/n) + (s2^2/n))
how to use Student’s t-test
find Student’s t-test value
work out degrees of freedom (sample size - number of data sets)
compare to value of t at 5% significance level
t-test < t at 5% = not statistically significant = accept null hypothesis
t-test > t at 5% = statistically significant = reject null hypothesis
null hypothesis example
there is no statistically significant difference between factor 1 and factor 2
correlation coefficient / Spearman rank correlation use
shows whether 2 sets of data are correlated or not
Spearman rank formula
rs = 1 - (6 times sum of difference between ranks squared) / no. of pairs of values(no. of pairs of values squared - 1)
factors for natural selection of advantageous characteristics
genetic variation
selection pressure
reproductive success
pesticide resistance method
pesticide acts as strong selection pressure
insects with no resistance will die
insects with some resistance more likely to survive and reproduce to pass on resistance characteristic
higher proportion of population have resistance
problems with pesticide resistance
predators eat insects with larger dose of pesticide
pesticide can move up the food chain to humans, potentially dangerous (don’t break down in ecosystem)
pests become harder to control
more destruction of crops, higher cost for farmers
antibiotic resistance method
presence of antibiotic = selection pressure
non-resistant bacteria die
resistant bacteria live longer and more likely to survive
can reproduce and pass on resistant characteristics so higher proportion of population are resistant
causes and impact of antibiotic resistance
overuse of antibiotics
incorrect use of antibiotics (not completely finishing course as patient already feels better)
causes strains of antibacterial resistant bacteria (e.g. MRSA)
Darwin observations and conclusions
offspring look similar to parents generally - characteristics passed down to next generation
no two individuals identical - genetic variation present
organisms have ability to produce lots of offspring - struggle to survive, better adapted individuals more likely to survive
population sizes in nature tend to remain fairly stable - struggle to survive, better adapted individuals more likely to survive
term for evolution of a new species
speciation
