Topic 7 - inheritance population evolution and ecosystems Flashcards

Question

What are dihybrid crosses?

Answer 1

A genetic cross where the inheritance of two genes is considered at the same time.

Answer 2

1. Parental phenotype. 2. Parental genotype. 3. Possible gametes 4. Offspring genotype. 5. Offspring phenotype. 6. Proportion of each phenotype.

Answer 3

Possible gametes: RY, Ry, rY, ry and RY, Ry, rY, ry

Answer 4

Crossing over results in new combinations of alleles in the gametes. This means the predicted gambit in your punnet square may differ.

Answer 5

All the alleles of all the genes within a population at one time.

Answer 6

All the individuals of one species in one area at one time that can interbreed to make fertile offspring.

Answer 7

The proportion of an allele within the gene pool

Answer 8

P + q = 1 P*2 + 2pq + q*2 = 1 P = the frequency of the dominant allele Q = the frequency of the recessive allele P*2 = the frequency of the homozygous dominant genotype 2pq = the frequency of the heterozygous genotype Q*2 = the frequency of the homozygous recessive genotype.

Answer 9

– Individuals within a population of a species may show a wide range of variation in the phenotype. – This is due to genetic and environmental factors.

Answer 10

– Mutation is the primary source. – However random fertilisation of gambit during meiosis introduces genetic variation.

Answer 11

Predation, disease and competition for the means of survival results in differential survival and reproduction.

Answer 12

They’re likely to produce more offspring and passed on their favourable alleles to the next generation. The effect of this differential reproductive success on the allele frequencies within energy pool.

Answer 13

When individuals which contain alleles coding for extreme traits are more likely to survive and pass on their alleles. As a result, the allele frequency changes and more individuals possess the allele for the extreme trait and the Midling trait allele becomes less frequent continued disruptive selection can immediately lead to speciation.

Answer 14

Speciation is the process that results in the creation of a new species. This occurs when one original population of the same species becomes reproductively isolated this isolation means that there are now two populations of the same species, but they cannot breathe together.

Answer 15

It can result in the accumulation of differences in their gene pool to the extent that two populations would be unable to interbreed to make fertile offspring, and are therefore classed as two different species.

Answer 16

Geographically isolated: Allopatric Changes in reproductive mechanisms: sympatric

Answer 17

- Populations can become separated geographically leading to reproductive isolation. – Within all populations there is genetic variation due to random mutations. – A population could become geographically isolated overtime by new mountain ranges or new bodies of water separating land masses. This separates the original population into two which are now unable to reproduce due to the geographical barrier.

Answer 18

– Populations can become reproductively isolated due to differences in their behaviour. – Individuals of the same species may not be separated by geographical barriers but are unable to reproduce. – This could be because a random mutation within the population could impact reproductive behaviour, for example it may cause individuals to perform a different courtship ritual or for individuals to be fair at different times of the year. – Due to this these individuals would not reproduce together and there will be no gene flow between the two groups within the populations. – Overtime these reproductively isolated populations will accumulate different mutations to the extent that their DNA is so different they cannot indeed to create offspring. They are therefore classified as two different species.

Answer 19

– This is the change in the allele frequency within a population between generations. – There will always be genetic drift from one generation to the next but continual substantial genetic drift results in evolution. – The smaller population is the bigger. The impact frequency changes have proportionally and this is why evolution of often occurs more rapidly in smaller populations.

Answer 20

A group of organisms of the same species living in the same area at the same time and can interbreed to make fertile offspring.

Answer 21

Part of an ecosystem, in which particular organisms live.

Answer 22

All the populations of different species are in the same area at the same time.

Answer 23

A community and the nonliving components of an environment, the biotic and abiotic factors. Ecosystems can range in size from the very small to the very large.

Answer 24

An organisms role within an ecosystem, including its position in the food web and habitat each species occupies its own leash governed by adaptation to both abiotic and biotic conditions.

Answer 25

The maximum population size an ecosystem can support.

Answer 26

The nonliving conditions of an ecosystem.

Answer 27

The living components of an ecosystem

Answer 28

They will affect the size of the different populations. These factors can range from temperature, oxygen and carbon dioxide concentration, light intensity, pH, and soil conditions. Plants and animals are adapted to abiotic factors within their system. These adaptations developed through the process of natural selection over many generations. The less harsh the abiotic factors such as plenty of water and light the large large of the range of species and the large of the population sizes.

Answer 29

When members of different species are in competition for the same resource that is in limited supply. This could be competition for a habitat food or water. The individual better adapted to the environment is more likely to succeed in this competition.

Answer 30

When members of the same species are in competition for resources and a maid competition for a main links to the courtship rituals individuals that are fitter with more energy to perform a more impressive courtship ritual or may have fur or feathers in a better condition to attract a female.

Answer 31

The interaction between predators and prey in a food web. The predator prey graph always follows the same dynamic. The size of the predator and prey population both fluctuate. What ever happens to the prey happens to the predators afterwards (delayed).

Answer 32

- Sampling is more time efficient and if implemented correctly, it can be more accurate. - Samples must accurately represent the population. This is insured by: Random sampling in uniform areas to eliminate bias. Line transects to examine a change over distance. Large number of samples.

Answer 33

Sample using a quadrat. It is uniformly ditrsibuted use random sampling. If it is uneven distribution use a line transect.

Answer 34

Sample using the mark–release–capture method.

Answer 35

1. Lie to tape measures at a white angle to create a gridded area. 2. Use a random number generator to generate two coordinates. 3. Place the quadrat and collect the data. 4. Repeat loads more.

Answer 36

The quadrat is placed at every position along the tape measure.

Answer 37

The quadrat is placed at uniform intervals along the tape measure

Answer 38

1. Place the tape measure at a right angle to the shoreline. 2. Place the quadrat every 5 m/every position. 3. Collect the data. 4. Repeat by placing another 30 transacts along the beach at right angles to the shoreline.

Answer 39

1. An initial sample of the population is captured. 2. These individuals are then marked and the number caught is recorded. (The mark must be whether resistant). 3. These marked individuals are released and are left for a period of time to allow them to randomly disperse throughout the habitat. 4. Then a second sample is captured. 5. The total number captured in the second sample and the number recaptured with the markings is recorded. 6. The size of the population is estimated on the principle that the proportion marked in the second sample is equal to the portion of marked individuals in the population as a whole.

Answer 40

Estimated total population = number of organisms initially caught x number of organisms in the second sample / number of marked organisms recaptured.

Answer 41

Ethical issues mean that it cannot be toxic must not increase chances of predation and must not reduce chances of reproduction.

Answer 42

- The population size is constant, so there is no birth no death and no migration. - The animals always redistribute evenly they may all huddle their food in reality.

Answer 43

Primary succession starts with a pioneer species colonising bear rock or sand. – Pioneer species are adapted to survive in harsh abiotic factors and through their death and decomposition change the abiotic factors to become less harsh and thin layers of soil and humus. – Smaller plants can now survive and further increase the depth and nutrient content of soil. The patting continues and the abiotic factors get less harsh and larger plants can now survive the environment further. Each species may change the environment in such a way that it becomes less suitable for the previous species therefore each existing species is out competed by a new species colonising. – Changes that organisms produce in their abiotic environment can result in a less hostile environment and increase by diversity. The final stage in succession is known as the climax community and this is dominated by trees.

Answer 44

The succession is distributed and plants are destroyed. Succession starts again, but the soil is already created so it does not start from the bear rock stage. The species richness and number of organisms increases a.k.a. the biodiversity. As succession occurs larger plants, species and animals start to colonise the area.

Answer 45

– Destruction of habitats is usually due to human activity resulting in a loss of food space and can lead to extinction to conserve habitats. Succession is often managed. – Maintaining earlier stages in succession and preventing a climax community. A greater variety of habitats are conserved and therefore a greater range of species. – Human behaviour needs to be monitored because of scarcity of natural resources.