4.3) Classification & Evolution Flashcards
what are the 3 domains?
1) bacteria
2) archaea
3) eukarya
what does the bacteria domain consists of ?
unicellular prokaryotic bacteria
what does the archaea domain consist of?
-unicellular prokaryotic organisms
-closer to eukaryotes
what does the eukarya domain consist of?
unicellular + multicellular eukaryote organisms
how many kingdoms are there?
5
what are the 5 kingdoms?
1) animalia
2) plantae
3) fungi
4) protoctista
5) prokaryota
what are some characteristics of the kingdom animalia?
-multicellular eukaryotic
-cells differentiate
-no cell wall
-heterotrophs
-communication = nervous system + chemical signalling
what are some characteristics of the kingdom plantae?
-multicellular eukaryotic
-cell wall
-vacuoles
-specialised cells
-chloroplasts = photosynthesis
-autotrophs
what are some characteristics of the kingdom fungi?
-eukaryotic
-chitin cell walls
-heterotrophs
-reproduce using spores
what are some characteristics of the kingdom protoctista?
-eukaryotic
-BOTH single cell + group of similar cell
-no cell wall
what are some characteristics of the kingdom prokaryotae?
-bacteria
-unicellular
-cell walls
-cytoplasm
-NO nucleus + mitochondria
-divide by binary fission
-can be both heterotrophic + autotrophic
why is fungi an autotroph?
-digest dead or decaying matter extracellularly
define autotroph
make their own nutrients = light + chemical energy
define heterotroph
cannot make their own organic mol.
what is taxonomy?
practice of biological classification
species are arranged into groups based on …
-evolutionary origins
-relationships
what is taxon?
group
what is the hierarchical classification system used for?
group similar organism together so they can be easily understood
how many groups are there in the classification system?
8
what are the groups in the classification system?
-domain
-kingdom
-phylum
-class
-order
-family
-genus
-species
define phylogeny
study of evolutionary relationships between orgnisms
what are some characteristics of the classification system?
-higher groups have more organisms
-organism lower down = more closely related
define classification
how organisms are arranged into different groups (taxonomic groups)
define species
2 individuals that can successfully mate with each other + produce fertile offspring. individuals in the same species tend to have similar physical appearance , anatomy, genetics, phylogeny + physiology
what was Charles Darwin’s theory?
theory of evolution
what were some of Darwin’s observations?
-not all offspring survive
-populations of the same species show variation = INTRASPECIFIC VARIATION
-offspring inherit characteristics from their parents
what are the evidence to support the theory of evolution/
1) fossil evidence
2) molecular evidence
what has fossil evidence provided us about the theory of evolution?
-showed that environments have changed significantly over millions of years
-fossils can be dated + put in a sequence = show how an organism changed through time
-shows similarities between extinct species
-provided evidence for gradual change
what are some molecular evidence that supports the theory of evolution?
-DNA can be sequenced = show evolutionary relationships + how genetic code has changed as they evolved
-differences in nucleotide sequence shows:
– more similar = more closely related
– very similar DNA = separated more recently
-create phylogenetic trees
what does variation mean?
differences between 2 or more things
what are the 2 types of variation that an organism can show?
1) genetic variation
2) phenotypic variation
what is genetic variation?
variation in the genotypes between species or within a species
what is phenotypic variation?
variation in phenotypes between species or within a species
what is INTERspecific variation?
variation between species
what is INTRAspecific variation ?
variation within species
why is interspecific variation useful?
identifying + classifying different species
what is discontinuous variation?
-QUALITATIVE differences
-discrete + distinguishable categories
-no intermediates
(e.g blood group)
what is continuous variation?
-QUANTITATIVE differences
-no distinct categories
-range of values
what are some causes of variation?
-genetic factors
-environmental factors
-combo of both
what are some causes of discontinuos variation?
-only due to genetic factors
-phenotype = genotype
-different genes have different effects
what are the causes of continuous variation?
-interaction between genetics + environment
-phenotype = genotype + environment
-different alleles have small effect
different genes can have the same effect –> can add together to have an ADDITIVE effect
what are the environmental factors that can cause continuous variation?
-changes in sunlight, supply of nutrients, availability of water, temp, oxygen levels can affect how organism grow + develop
-variation caused by the environment CANNOT be inherited
define mean
average
what is the equation for mean?
sum of all measurements ÷ number of measurements
what is the symbol for mean in calculations ?
X̄
what does standard deviation measure?
spread of data over a mean value
what is the formula for standard deviation?
(∑(x−¯x)^2
√ ——————-
n
what is the t-test used for?
compare the means of 2 data, to see whether they are significantly different or not
what is a null hypothesis?
a statement which expect for their to be no significant difference
when can the null hypothesis be rejected?
when there is a statistically significant difference
what are the steps to the t-test?
1) calculate mean for both data sets
2) calculate SD
3) square SD and ÷ by n
4) add step 3 values together and then square root
5)divide the mean difference by step 4
6) calculate degrees of freedom = (n1-1) + (n2-1)
how can you tell if something is statistically significant?
t value greater than critical value = null hypothesis rejected
when can the null hypothesis be rejected during a t-test?
t value less than critical value
what does SPearman’s rank correlation show?
whether there is a correlation between 2 variables that don’t show normal distribution
what is the equation for Spearman Rank correlation?
𝑟 = 1−6∑𝑑^2
—————–
𝑛(𝑛^2−1)
what is selection pressure?
environmental factors that affect the chance of survival of an organism
define adaptations
features that make an organism better suited for its environment + then can survive + reproduce
what are the 3 types of adaptations?
1) anatomical
2) physiological
3) behavioural
what are anatomical adaptations?
structural or physical features
what are physiological adaptations?
biological processes within the organism
what are behavioural adaptations?
the way an organism behaves
define evolution
change in adaptive features of a population over time as a result of natural selection
what is convergent evolution?
when species that do not share a common ancestor + live in different parts of the world = show very high levels of similarity between adaptations
what is an example of convergent evolution?
marsupial mole + European mole
how are marsupial moles + European molesan example of convergent evolution?
-both burrow through soil
-short + powerful limbs
-no external ears
-limited eyesight
-very similar, highly silky fur
what is genetic variation ?
differences in DNA base sequences between individual organisms within a species
what is the genetic variation between organisms of the same species?
-similar genomes
-differences between DNA base sequence
what are some effects of genetic variation?
-natural selection
-differences in phenotypes
-increases the chance for those with more specific phenotypes of surviving –> pass alleles onto offspring
-higher adaptations = better suited environment for environment
what is an advantage of having a large gene pool ?
strong ability to adapt to change
what is a disadvantage of having a small gene pool?
-very low genetic diversity
-less adaptable to change
-vulnerable to extinction
why do environmental factors act as a selection pressure?
affect the chance of survival
what are the main processes during natural selection?
-random mutations produce new alleles
-new alleles = increases chance of survival + reproductive success
-passed onto next generation
-new allele will increase in frequency
what is an antibiotic?
chemical substances that inhibit / kill bacteria cells
how do bacteria become resistant to antibiotics?
-mutations within bacteria population on resistance
-antibiotic = resistant bacteria don’t die
-less competition from the non- resistant bacteria
-reproduce = genes for resistant bacteria are passed on
-whole population become resistant
what is a pesticide?
chemical that kill pests of any kind
what are the various types of pesticides?
-insecticides
-herbicides
-fungicides
-molluscicides
-rodenticides
what are pesticides used for?
-control the pest that consume or damage human food crops
-kill insects that vectors of disease
what is a selective agent?
-environmental factor that influences the chance of survival of particular species
-drives natural selection
what are some consequences of antibiotic resistance?
-overuse of antibiotics = exert selective pressure on the bacteria = help evolution of resistance
-some bacteria can be resistant to multiple antibiotics
-common antibiotics are becoming less effective = overuse of antibiotics when not necessary + large scale use of antibiotics –> increase resistance
how can we reduce antibiotic impact?
-avoid overuse of antibiotics
not being used in non-serious infections
-finishing the entire course
-not being used of viral infections
-only used antibiotics that are highly specific to the infection
how can the spread of already resistant strains be limited?
-good hygiene practices
-isolating infected patients
what are some consequences of pesticide resistance?
-problem for the security of future food supplies
-used sparingly or rotation
-using combination of pesticide can delay the spread of resistance
-use biological control
-using selectively bred or genetically modified pest resistant
