unit 5 Flashcards
Define evolution
the cumulative change in the heritable characteristics of a population
use an example to explain how selective breeding has lead to evolution in a species
From the ancestors of wolves and with the selective breeding by humans, these ancestor wolves have evolved into modern wolves and dogs, who themselves were bred selectively to evolve into different dog breeds.
explain the process of artificial selection using selective breeding
rather than having forces of nature act as the selective pressure, with artificial selection humans act as the selective force by choosing particular phenotypic animals or. plants with the desirable characteristic(s). This selective breeding has lead to large changes in species over time.
state and example of analogous structures
state and example homologous structures
butterfly wing and bat wing
bones in the forelimbs of different animals
contrast convergent evolution and adaptive radiation
convergent evolution is when species who are not closely related independently evolve similar traits as a results of having to adapt to a similar environment. This trait is not shared due to common ancestry.
Divergent evolution occurs when two species with a common ancestor become more different as they adapt to unique environment conditions.
Adaptive radiation is a form of divergent evolution in which new species quickly evolve from an ancestral species when new habitat becomes available and the new species can rapidly different to fill ecological niches
contrast analogous structures and homologous structures
homologous structures are similar in position, structure and evolutionary origin but not necessarily in function
Analogous structure perform a similar function but have different evolutionary origin
explain how continuous variation across geographical ranges is evidence of evolutionary change
closely related species or populations within the same s will show variation across geographical ranges as they adapt to their environment. Evolutionary. Related species can be found on. different continents, as they shift and move, species can be isolated and evolve separately. However they will share homologous structure as a result of common ancestry.
describe the process of gradual speciation
gradualism is the process by which evolution proceeds by the accumulation of gradual changes.
List sources of genetic variation.
Mutation- the change in the nucleotide sequence in DNA
Meiosis- via either crossing over in prophase 1 or ideèendent assortment of genes on different chromosomes during metaphase 1.
Sexual reproduction- the joining of genetic material from two parents to create a new combination of genes in the offspring.
Explain the effect of the selective pressure on the more and less adapted individuals in a population.
Selective pressures affect individuals differently with beneficial variations in behaviour or physical traits, as they are better adapted to survive and produce more offspring. The least well adapted do not survive and reproduce difficulty. This leads to a shit in the population- more individuals with the adaptation
Explain the cause of the change in frequency of traits in a population through natural selection.
due to differential survival and reproduction. Better adapted animals survive and reproduce, which increases the frequency of the adapted trait over time.
Explain how natural selection leads to changes in the beaks of Galapagos finches with changes in weather conditions.
There is overproduction of finches in the population
The finches have variations in their beak shape
There is a selective pressure, such as a drought causing shortage of small seeds.
There are differential survival and reproduction rates. Birds with larger stronger beaks are able to crack bigger seeds. These birds eat the seeds which produce energy to survive and reproduce.
In just a generation the frequency of the larger beak increases in the population.
List reasons why evolution of antibiotic resistance has been rapid.
The antibiotic resistance crisis has been attributed to the overuse and misuse of these medications, as well as a lack of new drug development by the pharmaceutical industry.
Outline the effect of not completing a full dose of antibiotics on the development of antibiotic resistance.
If you fail to complete a course of antibiotics, the most resistant bacteria are able to survive and will result in the bacterial population in the afflicted person having a higher resistance to that antibiotic. As a result the surviving bacteria that is reproducing cannot be treated with the same antibiotic, and if the infection is passed on, that person can also not be treated with the antibiotics.
Explain how natural selection leads to changes in antibiotic resistance.
Antibiotic resistance occurs when a population of bacteria changes in a way that reduces the effectiveness of an antibiotic.
It arises through natural selection like this:
There is overproduction of bacteria in the population
The bacteria have variation in their susceptibility to an antibiotic
The antibiotic serves as the selective pressure, killing bacteria that are not resistant
There is differential survivaé and reproduction, the resistant bacteria continue to live on and divide. The non resistant die.
Over generation the frequency of the resistance trait increases in the population.
