10 Evolution and classification Flashcards by Dawn Parker

what is the definition of classification?

the grouping of organisms based on the similarity of features

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what is taxonomy?

the science of studying classification and the differences between species

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what is phylogeny?

the study of evolutionary relationships between organisms

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what is a species?

a group of organisms which can interbreed successfully to produce fertile offspring

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what common traits do species share?

genetics

biochemical features

physiological features

anatomical features

ecological niche

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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

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what is a criticism of the BSC?

it does not consider species that reproduce asexually

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what is the phylogenetic species concept (PSC)?

a group of organisms that share a common ancestor and have the same evolutionary history

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what are two advantages of the PSC?

a continuous tree ∴ doesn’t have to definitively classify

avoids misleading hierachy

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what are the 8 taxons (from largest to smallest)?

Domain

Kingdom
Phylum
Class
Order
Family
Genus
Species

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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

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what are the three domains?

Eubacteria

Archaebacteria

Eukaryota

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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

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which proteins are primarily used in classification?

haemoglobin

cytochrome C

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how are anatomical features used for classification?

similar organisms grouped

members of same species can look v. different
does not account for convergent evolution

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how are fossils used for classification?

DNA can be retrieved from recent fossils for molecular analysis

evolutionary relationship estimated using morphological features

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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

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how can embryological evidence be used for classification?

early embryos can look very similar

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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

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why is mitochondrial DNA often used in DNA barcoding?

has a faster rate of mutation than chromosomal DNA

∴ produces significant difference in genetic sequence

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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