chapter 9 - genetic diversity and adaptation Flashcards
How were classification system’s formed and how are they different now
Classification systems used to be based on observable features however now we use genetic comparisons that can be made by different species by direct examination of the base sequence of DNA, the base sequence of mRNA all the proteins encoded by DNA and mRNA
What is biodiversity/biological diversity
It is reflected in the vast number of species of organisms, these different says reflect genetic differences in the variation of individual characteristics within a single species
What is genetic diversity
The total number of alleles of a gene in a population. The greater the number of alleles the greater the genetic diversity of that species. enables natural selection to occur
What is allele frequency
How often a particular allele appears in a population
What is the cause of genetic diversity
All members of the same species have the same genes. Organisms differ in the alleles. It is a combination of alleles in an organism that makes individuals within a species different from each other.
Changes in genetic Diversity
Genetic diversity within a species can be caused by, a random mutation in the DNA resulting in new alleles of a gene.
Why do we use phylogenetics
To see how closely related the organisms among various taxonomic groups are. It assumes that’s all organisms have an evolutionary history that’s began with an ancestor
What is DNA hybridization
Allows scientists to find similarities between the DNA of different species.
1) DNA from the two species is extracted, purified and cut into shorter pieces
2) The DNA of one of the organisms is labeled with a fluorescent radioactive marker and then is mixed with the unlabeled DNA to be compared against.
3) The mixture is heated to allow DNA strands to disassociate and become single strands
4) The mixture is allowed to cool so that’s DNA strands with complementary base sequences combine
hybridised sequences with a greater similarity will have more base pairing and will bind more firmly.
after. mixtures are heated again at temperature increments to analyze how many stands have separated from their hybrid.
less hybridization, more different the two DNAs are
Describe the process of natural selection
Within a population that is a gene pool with a variety of alleles. However in certain environments there may be an allele with a advantage over other individuals in a population. These individuals are more likely to obtain available resources and grow rapidly and live longer, they are better adapted to survive. These individuals have a better chance of breeding. Only individuals that reproduce successfully will pass on their alleles. Therefore they new allele passed to the parents is most likely going to pass on to the next generation. as new individuals have the advantageous allele they are more likely to survive and reproduce successfully. Over many generations the number of individuals with the new Allele will increase. Overtime the frequency of the new advantageous allele in the population increases while that’s of the non-advantageous allele decreases.
Behavioral and behavioral adaptations
Behavioral-These are acts which an organism does to increase its chances of survival and reproduction.
Behavioral adaptations-When a hedgehog is startled It curls into a ball with its spikes up. huddling reduces surface area to volume ratio, reducing heat loss.
Birds keep themselves warm by cuddling with each other
Physiological and physiological adaptations
physiological-Processes inside and organisms body that increases its chance of survival and reproduction
Physiological adaptations-Arctic fish contain an anti-freeze protein which prevents them from freezing in very cold waters, therefore they are able to survive and reproduce and pass on this beneficial gene to their offspring.
Anatomical and anatomical adaptation
Anatomical-Structural external features which increase an organisms chance of surviving and reproducing
Anatomical adaptations-Common wombat,They have small ears and short strong legs. Sharp claws for digging borrows, rounded body weight. Females have a pouch were Young can grow and be protected.
Define evolution
Evolution is The gradual change an allele frequency Within a population over time. occurs due to natural selection
what is the niche of a species
The role within the environment. Species which share the same niche compete with each other
Describe and explain directional selection
Happens when the environmental conditions change and the phenotypes best suited to the new conditions are more likely to survive. And these individuals breed and produce offspring. Overtime the mean of the population will move in the direction of these individuals. the change is in One Direction
Describe and explain stabilizing selection
In stabilizing selection the phenotypes with successful characteristics are preserved and those of greater diversity are reduced. However the selection does not occur due to changes in the environment. If the environment stays the same then the individuals closest to the mean are favored because they have the alleles that have given them the survival advantage. The furthest from the mean are selected against.
When does directional selection occur
When there is a change in environment
When does stabilising selection occur
When there is no change in environment
Why is a low biodiversity possibly not a concern by decrease in diversity a cause for concern
hello biodiversity might not be a concern for example you would expect this in an Artic or in desert conditions
however a decrease in diversity is a cause for concern, and this is often caused by human activity
What are five farming techniques that reduce biodiversity
destruction of hedgerows selective breeding monocultures overgrazing Filling in ponds and draining wetlands
How do you interpret the diversity index
The lowest value you can get for the diversity index is one
The larger the value for the diversity index means of the greater the species diversity
Investigating diversity: you can investigate genetic diversity within or between species by comparing:
The frequency of observable characteristics
The base sequence of DNA The base sequence of mRNA
Amino acid sequence of proteins
Why does destruction of hedgerows reduce biodiversity
this destroys a habitat for local species and small mammals and insects in the area
How does selective breeding reduce biodiversity in the area
Plants or animals that display desirable characteristics of selectively bred to reproduce therefore the desirable characteristic is displayed in the next generation. however this narrows down the gene pool and you don’t have as much biodiversity/diversity in the area
