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Flashcards by ashiana121, updated more than 1 year ago
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Created by ashiana121
over 9 years ago
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| Question | Answer |
| What is meant by 'biodiversity'? | The variety of all the life on earth |
| What are the three types of biodiversity? | - Intraspecific - Interspecific - Ecosystem |
| What is meant by intraspecific diversity? | Variety of alleles within a species |
| What is meant by ecosystem diversity? | The variety of habitats within an ecosystem |
| What is meant by intraspecific diversity? | The variety of species within a habitat |
| What is another name given to intraspecific diversity? | Genetic diversity |
| Intraspecific (genetic) diversity can be due to variation in DNA or variation in ___________ | Environment |
| How do new alleles arise? | Due to mutations |
| What are the two types of genetic diversity? | Continuous and discontinuous diversity |
| What is meant by continuous diversity? | When the characteristic has a continuous range of values e.g height - the frequency histogram is a fairly smooth curve |
| In continuous data the characteristics: (4) | - Have no distinct categories - Tend to be quantitative - Controlled by a large number of genes (polygenic characteristics) - Significantly affected by the environment |
| Give some examples of continuous characteristics in intraspecific diversity | Height, hair colour, heart rate, intelligence, growth rate, rate of photosynthesis |
| What is meant by discontinuous variation? | When the characteristics have a few discrete categories |
| In discontinuous variation the characteristics: (4) | - Have a few distinct categories into which individuals can be placed - Tend to be qualitative, with no overlap between categories - Controlled by one gene, or by a small number of genes - Are unaffected, or only slightly affected by the environment |
| Discontinuous characteristics are ____ in humans | Rare |
| Discontinuous characteristics are common in ______ | Plants |
| What are some examples of discontinuous characteristics? | Human blood group, ear lobes attachment, flower colour, seed colour |
| Why are these characteristics useful for geneticsists? | They give clear cut results |
| What is genetic diversity the basis for? | Evolution and survival of a species |
| Why is a species with a high genetic diversity more likely to have more members that survive in a change in the environment? | It is more likely to have individuals with the characteristics required to survive in the change of environment |
| Some populations have low genetic diversity due to natural or human causes. What are these 3 causes? | - Genetic bottlenecks - Founder Effect - Selective breeding |
| What is meant by a genetic bottleneck? | When a population is drastically reduced in size due to a natural catastrophe or a continual, more gradual change in the environment |
| Why does this mean the genetic diversity is reduced in the smaller population? | Small populations generally have a smaller range of alleles - if they reproduce and the population increases again there will be reduced genetic diversity |
| Why will the genetic diversity gradually increase in the new population? | Due to mutations |
| The vast majority or intraspecific variation is caused by what? | A combination of genes and environment |
| What is the name given to the technique that is useful for studying the causes of variation in humans? | Twin studies |
| What does this entail? | Variation in characteristics in identical twins compared to variation in the same characteristics between non-identical twins (or just siblings) |
| Why will the variation between the identical twins probably be due to environmental causes? | Because they have identical genes |
| What is meant by the founder effect? | When a small number of individuals colonies a new habitat and start a new isolated population |
| The few individuals will only have a small range of alleles between them so the founder effect is and example of what? | A genetic bottleneck |
| What does this mean about the new populations made in terms of genetic diversity? | They will have low genetic diversity |
| What is another term used to describe selective breeding? | Artificial selection |
| What do these terms mean? | The controlled breeding of animals or plants by humans so that only individuals with certain characteristics are allowed to reproduce |
| Selecting certain alleles and rejecting others during selective breeding means the genetic diversity of the animals or plants is _______ | Reduced |
| What is the purpose of selective breeding? | The change species so that they are more useful to humans |
| What does this result in? | New breeds of animals and new varieties of plants |
| Why are these new breeds sometimes recognised as new species? | They can no longer interbreed with the wild populations |
| Why are selectively breeding animals and plants not able to survive well in the wild and why are they highly susceptible to changes in the environment? | Because they have such a low genetic diversity and are out-competed by wild species with greater diversity |
| What can intense selection lead to in terms of domesticated animals? | The development of physical problems |
| Why wouldn't these fully develop in the wild? | They would disappear due to competition |
| What ethical argument does this arise? | Whether we are causing harm to the animals by selectively breeding them |
| All the organisms living in a habitat are collectively called its _________ | Community |
| What does interspecific diversity (or species diversity) mean? | The variety of species in a community |
| Why is species diversity useful? | It tells us about the complexity, quality and stability of an ecosystem |
| In order to measure species diversity we need to ____ ________ | Take samples |
| What is meant by the 'species richness' of a sample? | The number of species in the sample |
| What does species richness not take into account which makes it less useful? | The abundance (size) of each species population |
| What is the calculation we use to measure the species richness and their abundance? | |
| What is D? | The Diversity Index |
| What is N? | N = total number of individuals (total abundance) |
| What is n? | n = number of individuals in each species |
| What is the relationship between the index and the species diversity? | The higher the index, the higher the species diversity |
| A community where one species is dominant over others has a ______ diversity than one where the species are more evenly populated | Lower |
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