4.10 - Classification and evolution Flashcards

Question

What two factors cause variation

Answer 1

- an organism's genetic material = genetic variation from differences in the genetic material an organism inherits from its parents - the environment in which the organism lives causes environmental variation

Answer 2

Alleles: - individuals in a species population may inherit different alleles of a gene - different alleles produce different effects Mutations: - changes to the DNA sequence and therefore to genes can lead to changes in the proteins that are coded for - can affect physical and metabolic characteristics - only passed on to offspring if mutation is in gametes Meiosis: - each gamete produces half the genetic content of a parent cell - before cytokinesis, the maternal and paternal genetic material is mixed through independent assortment and crossing over - leads to gametes of an individual showing variation (Sexual reproduction Chance during sexual reproduction )

Answer 3

- a characteristic that can only result in certain values - there can be no intermediate values - purely genetic variation - usually represented using bar chart or pie chart - e.g. biological sex, bacteria shape, human blood groups

Answer 4

- a characteristic that can take any value within a range - there is a graduation from one extreme to the other - controlled by a number of genes and often influenced by environmental factors - collected into a frequency table and plotted as a histogram to show the trend

Answer 5

- when continuous variation data are plotted on a graph, the usually result in the production of a bell-shaped curve known as anormal distribution curve - mean, median and mode are the same - graph is symmetrical about the mean (50% of values are less than the mean and 50% are greater) - most values lie close to the mean value, the number of individuals at the extremes are low - when you calculate the standard deviation you will generally find that 68% of values are within 1 standard deviation of the mean (95% =2, 99.7%=3)

Answer 6

- used to compare the means of data values of two populations - to use this the data collected must be normally distributed and enough data must be collected to calculate a reliable mean - different sample sizes may be used

Answer 7

- used to consider the relationship between two set of data - find if the data has no correlation, positive correlation or negative correlation

Answer 8

characteristics that increase an organism's chance of survival and reproduction in its environment - anatomical adaptations - behavioural adaptations - physiological adaptations

Answer 9

- body covering (e.g. to stay warm or provide protection) - camouflage, making it harder for predators or prey to spot it - teeth, the shape and type relate to its diet - mimicry, copying another animal's appearance or sounds fools predators into thinking it is dangerous

Answer 10

Adapted to reduce rate of transpiration: - curled leaves - hairs on inside surface of leaves - sunken stomata - thick waxy cuticle

Answer 11

- survival behaviours such as freezing or playing dead - courtship behaviours to attract a mate - seasonal behaviours such as migration (moving to a region where environmental conditions are more favourable) and hibernation (temperature, breathing and heart rate slow to conserve energy when there is little food)

Answer 12

- innate/ instinctive (ability to do it is inherited through genes such as spiders building webs) - learned behaviour (learnt from experience or observing other animals such as the use of tools)

Answer 13

- poison production (reptiles producing venom to kill prey or plants producing poisonous leaves to protect from herbivory) - antibiotic production (some bacteria to kill other competition) - water holding (frog, cacti holding water so they can survive without regular access to water)

Answer 14

Convergent evolution = when unrelated species share similar traits, because both organisms are adapting to similar environments or other selection pressures Analogous structures = different structures that have adapted to form the same function, but have a different genetic origin

Answer 15

Marsupial and placental mice: - both ere small, agile climbers that live in dense ground cover and forage at night - very similar in size and body shape - marsupial mice are in Australia and have a marsupium pouch Flying phalangers and flying squirrels: - both are gliders that eat insects and plants Marsupial and placental moles: - both burrow to find worms and grubs and have streamlined shape and modified forelimbs for digging - differ in fur colour Aloe and agave: - both adapted to survive in desert and have a similar appearance - aloe evolved in Sub-Saharan Africa - agave evolved in Mexico

Answer 16

1. organisms within a species show variation in their characteristics that are caused by genetic variation. For example they may have different alleles of a gene for a articular characteristic (sometimes created by genetic mutation) 2. 'survival or the fittest' organisms whose characteristics are best adapted to a selection pressure such as predation, competition or disease have an increased chance of surviving and successfully reproducing. Less well adapted organisms die or fail to reproduce 3. successful organisms pass the allele encoding the advantageous characteristic to their offspring. 4. this process is repeated every generation. Over time, the proportion of individuals with the advantageous adaptation increases. Therefore the frequency of the allele that codes for this particular characteristic increases in the population's gene pool 5. Over very long periods of time, many generations and often involving multiple genes, this process can lead to the evolution of a new species

Answer 17

- MRSA (methicillin resistant S. aureus) is resistant to many antibiotics - bacteria reproduce very rapidly, so can evolve over a short period of time - when bacteria replicate, their DNA can be altered - this lead to a mutation in some S. aureus that provided resistance to methicillin - when the bacteria was exposed to methicillin, only the bacteria with the mutation survived, passing on the resistant allele to their offspring - over time the number of resistant individuals in the population increased

Answer 18

- most peppered moths before the industrial revolution were pale coloured (due to a different allele) - this provided camouflage against light-coloured tree bark, increasing chances of survival - the industrial revolution in the 19th century caused dramatic changes in the moth's environment, as trees got darker from soot and the loss of lichen - the dark moths were now better adapted to be camouflaged - more dark coloured moths survived and reproduced, increasing the proportion of dark moths and the dark coloured allele in the population, especially near industrial towns and cities - deindustrialisation and the clean air act means that not there is a higher proportion of light coloured moths

Answer 19

- lay their eggs in fecal matter around a sheep's tail - larvae hatch and cause sores known as 'flystrike' which is usually fatal - 1950s Australia, pesticide diazinon was used to kill blowflies - within six years, blowflies developed a high level of resistance to diazinon - pre-adaptation (when an organism's existing trait is advantageous to a new situation) contributed to the development of diazinon resistance, as the flies had pre-existing resistance to a similar pesticide

Answer 20

- scientists found a new strain of flavobacterium living in waste water from factories that produce nylon 6 - strain of bacteria had evolved to digest nylon 6, therefore being beneficial to humans as they help to clear up factory waste - bacteria uses enzymes called nylonases, providing them with another source of nutrients - nylonases are unlike any other enzymes found in flavobacterium, so scientists believe that a gene mutation occurred to produce these enzymes (gene duplication combined with frame shift mutation)

4.10 - Classification and evolution Flashcards

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