Back to AI Flashcard MakerBiology /Biology IB HL - 5.2 Natural Selection Part 3
What basis do biological adaptations have?
Biological adaptations have a genetic basis (i.e. encoded by genes) and may be passed to offspring when the parents reproduce
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Term
Definition
What basis do biological adaptations have?
Biological adaptations have a genetic basis (i.e. encoded by genes) and may be passed to offspring when the parents reproduce
What type of organism is more likely to survive, in terms of adaptations?
Organisms with beneficial adaptations will be more likely to survive long enough to reproduce and pass on these genes
What happens to an organism not adapted?
Organisms without these beneficial adaptations will be less likely to survive long enough to reproduce and pass on their genes
Therefore what do adaptations result in in terms of reproduction?
Hence adaptations result in differential reproduction within a species, allowing for natural selection to occur
What can the variation in a population be considered to be, due to alleles?
The variation that exists within a population is heritable (i.e. genetic) and determined by the presence of alleles
How may alleles be passed down?
These alleles may be passed from parent to offspring via sexual reproduction
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| Term | Definition |
|---|---|
What basis do biological adaptations have? | Biological adaptations have a genetic basis (i.e. encoded by genes) and may be passed to offspring when the parents reproduce |
What type of organism is more likely to survive, in terms of adaptations? | Organisms with beneficial adaptations will be more likely to survive long enough to reproduce and pass on these genes |
What happens to an organism not adapted? | Organisms without these beneficial adaptations will be less likely to survive long enough to reproduce and pass on their genes |
Therefore what do adaptations result in in terms of reproduction? | Hence adaptations result in differential reproduction within a species, allowing for natural selection to occur |
What can the variation in a population be considered to be, due to alleles? | The variation that exists within a population is heritable (i.e. genetic) and determined by the presence of alleles |
How may alleles be passed down? | These alleles may be passed from parent to offspring via sexual reproduction |
What may alleles encode for? | Alleles encode for the phenotypic polymorphisms of a particular trait and may be beneficial, detrimental or neutral |
What can beneficial alleles do? | Beneficial alleles will better equip the organism to survive and hence produce more offspring (encodes beneficial adaptations) |
What can detrimental alleles do? | Detrimental alleles will harm the survival prospects of an organism, leading to fewer viable offspring |
What will neutral alleles do? | Neutral alleles will not affect the organisms survival prospects |
What will natural selection do to allele frequency? | Due to natural selection, the proportion of different alleles will change across generations (evolution) |
How do beneficial alleles affect reproductive prospects? | As beneficial alleles improve reproductive prospects (more offspring), they are more likely to be passed on to future generations |
How do detrimental alleles affect reproductive prospects? | Conversely, detrimental alleles result in fewer offspring and hence are less likely to be present in future generations |
How may environmental conditions change allele frequency? | If environmental conditions change, what constitutes a beneficial or detrimental trait may change, and thus the allele frequencies in a population are constantly evolving |
What is adaptive radiation? | Adaptive radiation describes the rapid evolutionary diversification of a single ancestral line |
When does adaptive radiation occur? | It occurs when members of a single species occupy a variety of distinct niches with different environmental conditions |
What does adaptive radiation result in? | Consequently, members evolve different morphological features (adaptations) in response to the different selection pressures |
Where can adaptive radiation be seen? | An example of adaptive radiation can be seen in the variety of beak types seen in the finches of the Galapagos Islands |
How do finches on Galapagos Island show adaptive radiation? | These finches have specialised beak shapes depending on their primary source of nutrition (e.g. seeds, insects, nuts, nectar) |
What inhabits Daphne Major? | Daphne Major is a volcanic island that forms part of the archipelago that is collectively referred to as the Galapagos Islands. It is the native habitat of a variety of bird species known as Darwin’s finches (subfamily: Geospizinae) |
What do Darwin's finches demonstrate? | Darwin’s finches demonstrate adaptive radiation and show marked variation in beak size and shape according to diet |
What beaks do birds that feed on seeds have? | Finches that feed on seeds possess compact, powerful beaks – with larger beaks better equipped to crack larger seed cases |
What changed the frequency of beaks? | In 1977, an extended drought changed the frequency of larger beak sizes within the population by natural selection |
What do dry conditions lead to? | Dry conditions result in plants producing larger seeds with tougher seed casings |
What specific change occurred to beaks due to the flood? | Between 1976 and 1978 there was a change in average beak depth within the finch population. Finches with larger beaks were better equipped to feed on the seeds and thus produced more offspring with larger beaks |