10 Evolution and classification Flashcards
what is the definition of classification?
the grouping of organisms based on the similarity of features
what is taxonomy?
the science of studying classification and the differences between species
what is phylogeny?
the study of evolutionary relationships between organisms
what is a species?
a group of organisms which can interbreed successfully to produce fertile offspring
what common traits do species share?
genetics
biochemical features
physiological features
anatomical features
ecological niche
what is the biological species concept (BSC)?
a group of organisms with similar morphological, physiological, biochemical and ecological features that can interbreed to produce fertile offspring
what is a criticism of the BSC?
it does not consider species that reproduce asexually
what is the phylogenetic species concept (PSC)?
a group of organisms that share a common ancestor and have the same evolutionary history
what are two advantages of the PSC?
a continuous tree ∴ doesn’t have to definitively classify
avoids misleading hierachy
what are the 8 taxons (from largest to smallest)?
Domain
Kingdom Phylum Class Order Family Genus Species
how does the binomial naming system use the taxons?
{Genus species} - e.g. Homo sapiens
can be abbreviated to H. sapiens
must be italicised or underlined when written
what are the three domains?
Eubacteria
Archaebacteria
Eukaryota
how is DNA used for classification?
genomes of 100+ species known
DNA codes for a specific sequence of amino acids ∴ more similarity in DNA –> closer relationship
which proteins are primarily used in classification?
haemoglobin
cytochrome C
how are anatomical features used for classification?
similar organisms grouped
- members of same species can look v. different
- does not account for convergent evolution
how are fossils used for classification?
DNA can be retrieved from recent fossils for molecular analysis
evolutionary relationship estimated using morphological features
how can immunological evidence be used for classification?
proteins from one species act as an antigen if injected from another species, provoking an immune response
similar species have similar antigens ∴ similar immune response ∴ similar antibody production
how can embryological evidence be used for classification?
early embryos can look very similar
what are the features of the optimum section of DNA for DNA barcoding?
universal to most taxa
short
universal variation between species
little variation within species
why is mitochondrial DNA often used in DNA barcoding?
has a faster rate of mutation than chromosomal DNA
∴ produces significant difference in genetic sequence
why is cytochrome C oxidase used as a measure of evolution?
short (68 pair) length
required for ATP synthesis in e- transport chain
∴ most organisms possess
which chloroplast genes are used in plants instead of cytochrome C oxidase?
rbcL
matK
what is an adaptation?
the possession of a feature that has increased the chances of survival of an individual to enable it to reach reproductive age and reproduce successfully
outline some ways in which adaptations are beneficial
finding sufficient food/photosynthesising effectively
finding sufficient nutrients and water
defending against predators and disease
surviving abiotic environments
responding to changes in the environment
communication with other members of the species to maintain social groupings and increase chances of reproducing
what are two behavioural adaptations in humans? how are they beneficial?
use of tools - obtaining protein- and energy-rich diets
social adaptations - maintaining social groups
what are two anatomical adaptations in humans? how are they beneficial?
bipedalism - travelling + freeing hands for tools
increased brain size - more information processing
what are two physiological adaptations in humans? how are they beneficial?
lactose tolerance in adult humans - obtaining Ca2+
skin pigmentation - melatonin pigmentation from UV-B radiation
how have plants adapted to:
- cold
- warm?
cold
- low-lying; dark leaves; dish-shaped flowers
warm
- light in colour; spines to reflect radiation
how have plants adapted to dry, arid ecosystems?
{xerophytes}
small external SA (e.g. by rolled leaves)
thick waxy cuticle
swollen stem
long roots to increase SA of water intake
stomata sunk into pits
how have plants adapted for aquatic habitats?
floating leaves
seeds + stem contain air for buoyancy
stomata on top of leaves for gas exchange
what three aspects of light affect the rate of photosynthesis?
intensity
wavelength
duration
give two examples of plant adaptations to maximise light intake
hydrophytes have floating leaves (air spaces)
deep water plants + algal species can absorb ‘blue’ wavelength light by becoming red/brown due to different photosynthetic pigments
why do plants require nitrates?
to make amino acids for proteins
how do plants obtain nitrogen and other minerals?
nitrogen fixation from the soil (although some soil types lack it - e.g. peat/bogs)
from trapped and digested animals
which gene is linked to language development in humans? how can we use it to estimate the evolution of language?
FOXP2
found in many species ∴ can estimate when mutations may have occurred
what can the fossil record tell us about language evolution?
all humans have language
first emigration from Africa ~ 50,000 years ago
∴ language evolved before this
what is the ‘vocal grooming’ theory of language evolution?
vocal grooming maintained social bonds in groups that became larger
began as simple sounds then evolved into more complex language
what is the ‘mother tongue’ theory of language evolution?
words and basic language evolved for communication between mother and offspring
what three things do we need to know to measure genetic diversity?
number of alleles per gene
heterozygosity
proportion of polymorphic genes
how is genetic diversity calculated?
number of polymorphic genes / total number of genes
{a higher value = more genetic diversity}
how does a mutation cause changes in the body?
change in DNA structure
change in gene
change in primary structure of protein
changes protein function
changes physical and metabolic characteristics
how is the effect of a mutation different in a somatic cell and a gamete?
somatic: affects the individual only
gamete: can be inherited by offspring
how does variation occur in meiosis?
random assortment of chromosomes in metaphase I
random assortment of chromatids in metaphase II
crossing over between sister chromatids
how does variation occur in sexual reproduction?
selection of mates and fertilisation is random
what are selection pressures?
environmental factors that drive evolution in a particular direction
give three examples of a selection pressure
threat of predation
disease
change in food/prey
climate change
presence of toxic chemicals
outline the process of natural selection
variation is present in the original population
a new allele arises from a mutation
individuals with a selective advantage have increased chances of survival ∴ more likely to survive and reproduce
allele with advantageous characteristics passed on to next generation
process repeated over many generations as proportion of individuals with advantageous characteristics increases
eventually a new species is produced
what is the definition of speciation?
the evolution of a new species
what is allopatric speciation?
when a geographical barrier separates two populations
causing them to experience different selection pressures
∴ different traits evolve
eventually they are different enough that they can no longer interbreed
what is sympatric speciation?
reproductive isolation
usually arises from allopatric speciation
e.g. can’t attract a mate; incompatible genitalia; different mating/flowering seasons
