8 Flashcards
Define the term ‘Adaptation’ ?
Adaptation : Characteristics that increase an organisms chances of survival and reproduction in it environment
Define the term ‘genetic bottleneck’ ?
Genetic bottleneck : an event that reduces the size of a population, which in turn reduces the genetic diversity of that population
Define the term ‘genetic drift’ ?
Genetic drift : Genetic drift is a random change in the frequency of alleles in a population
Define the term ‘speciation’ ?
Speciation - Speciation is how a new kind of plant or animal species is created
Define the term ‘stabilising selection’ ?
Stabilising selection - Stabilising selection is a form of natural selection wherein individuals with moderate or average phenotypes are better suited to their environment
Define the term ‘ disruptive selection’ ?
Disruptive selection - A type of natural selection that favours individuals with extreme traits, while individuals with intermediate traits are less likely to survive
What are the different types of adaptations ?
- Anatomical adaptations ( physical features which can be external/ internal )
- Behavioural adaptations ( how an organism acts, either inherited or learnt from their parents )
- Physiological adaptations ( processes that take place inside an organism )
Name examples of anatomical adaptations ?
- Body covering ( eg. hair, scales, spines, shells… ) : can help organisms fly, stay warm, provide protection and prevent water loss / sun damage in plants
- Camouflage : Allows organisms to blend within its environment making it hard for predators to spot it
- Teeth : Shape and type depends an organisms diet
- Mimicry : Copying other animals appearance or sounds allows a harmless organism to fool predators into thinking they are dangerous/ poisonous
What are the types of behavioural adaptations ?
- Innate/ instinctive behaviours
- Learned behaviours
What are innate/ instinctive behaviours ?
The ability to perform behaviours due to inherited genes allowing organisms to survive in habitat in which it lives
What are learned behaviours ?
They are adaptations learnt form experience/ observing other animals
Name examples of the behavioural adaptations ?
- Survival behaviours : playing dead/ freezing
- Courtship : Many exhibit elaborate mating rituals to attract a mate increasing chances of reproducing
- Seasonal : Allow organisms to cope with changes in their environment
What are the two types of seasonal behavioural adaptations ?
- Migration
- Hibernation
What is migration ?
Migration : Animals move from and to regions and back when environmental conditions are more favourable ( ie. climate, source of food… )
What is hibernation ?
Hibernation : A period of inactivity in which an animal/s body temperature, heart rate and breathing rate slow down to conserve energy reducing requirement for food
Name examples of physiological adaptations ?
- Poison production : Many reptiles produce venom to kill prey/ plants to protect themselves from being eaten
- Antibiotic production : Some bacteria produce antibiotics to kill other bacteria species in surroundings
- Water holding : Allows animals to survive in the dessert/ hot environments where there is no access to water ( eg. cacti )
What is evidence for convergent evolution ?
Analogous structures, it shows evidence for convergent evolution where natural selection drives species to have the most efficient and practical structures for specific functions
What are analogous structures ?
Analogous structures : Structures adapted to perform the same function but have different eugenic origin
What are homologues structures ?
Homologous structures : structures that have similar genetic origin but may have different functions in an organism
Define the term ‘natural selection’ ?
Natural selection : The process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes
What is selection pressure ?
Selection pressure are factors that affect an organisms chance of survival/ reproductive success
Explain how natural selection occurs ?
- Organisms within a species show variation in the characteristics that are caused by differences int heir genes/ genetic variation ( can be caused by mutation )
- Organisms whose characteristics are best adapted to the selection pressure/ environment have an increased chance of survival and successfully reproducing
- Organisms pass an advantageous allele onto there offspring
- This process is repeated for generations and increases the frequency of organisms counting the advantageous allele/ characteristic in a population
- Over long periods of time many generations, this leads to evolution of new species
Name modern examples of evolution ?
- Antibiotic-resistant bacteria
- Pesticide-resistance in insects
Explain antibiotic resistance in bacteria ?
- Bacteria reproduce very rapidly and so evolve in assort period of time
- Mutations can occur within their DNA leading them to contain a gene which codes for antibiotic resistance
- Resistant bacteria have a higher chance of survival and reproduce, passing on the allele for the antibiotic resistance to their offspring
- Over time, frequency of resistant individuals within the population increases
Explain how peppered moths evolved ?
- Initially, light- coloured moths where provided camouflage against light-coloured tree bark
- Industrial revolution caused many trees to become darker
- Darker moths wee now better adapted causing them to survive and reproduce
- Increased the frequency of dark moths in the population
Define the term ‘Pre-adaptation’ ?
Pre-adaptation : When an organism’s existing trait is advantageous for a new situation
Explain how sheep blowflies evolved ?
The alteration in DNA that caused the pre-existing resistance allowed the flies to rapidly develop resistance to pesticides so they were able to adapt / evolve at a much faster rate
