Continuity of Life ppt 2

What is selective breeding?

Selective breeding is where humans select the parents to breed, and may continue to choose offspring with desired characteristics.

Why does artificial selection not give control over genotype?

Selecting phenotypes does not give full control of genotype as throwbacks occur from hybrid parents, meaning recessive alleles are not eliminated.

What are advantages of natural selection?

Advantages include that it removes unfit variants and the organisms are suited to their natural environment.

What are disadvantages of natural selection?

Disadvantages include that it is a slow process as not all undesirables eliminated (it takes many generations), unfit phenotypes may be able to breed if selection pressure is weak, and low removal of recessive mutations.

What are advantages of artificial selection?

Advantages include outbreeding can occur by selecting genetically diverse parents and organisms with desired characteristics can be selected to produce offspring.

What are disadvantages of artificial selection?

Disadvantages of artificial selection is that it is suited to human purposes, not necessarily beneficial for the organisms, organisms often become unfit in comparison to wild variants, produces individuals who are genetically similar.

What are advantages of transgenic selection?

Advantages include that the next generation can all have desired traits and creates organisms to suit a specific environment.

What are disadvantages of transgenic selection?

Disadvantages include that it creates transgenic organisms without knowing the full effect on the environment (biotic or abiotic) or on the organism.

How does mate selection affect the gene pool?

Mate selection affects the gene pool as random mating occurs in many animals. If there is mate selection, then there is not random mating of gametes, and certain combinations come together at a much higher frequency than would occur by chance alone. This alters the frequency of alleles with subsequent generations.

How does gene flow between populations affect the gene pool?

Immigration and emigration has the effect of adding and taking away alleles from a population, changing allele frequencies.

What is allopatric speciation?

Allopatric speciation, also known as geographic speciation, occurs when biological populations of the same species become isolated from each other to an extent that prevents or interferes with interbreeding even when the barrier is removed. They form a new species if they no longer interbreed naturally.

What is evolution?

Evolution is the changes in gene pool of a group (e.g. population) from generation to generation through random and non-random mechanism.

What is microevolution?

Microevolution refers to varieties within a species. e.g variation in dogs

What is macroevolution?

Macroevolution is the evolution of new major taxa such as new species. genus, order, class. e.g. fish descending from an invertebrate animal.

What is the problem with macro-evolution?

The problem with macro-evolution is that it causes irreducible complexity, since many mutations must occur at one time and be inherited.

What is convergent evolution?

Convergent evolution is where distantly related species that live in similar environments develop similar adaptations. e.g. all ant eating mammals have long pointed noses and jaws and long sticky tongues.

What is divergent evolution?

Divergent evolution is where characteristics have come from the same ancestor changing, but also changing differently between offspring groups over time.

How does divergent evolution occur?

Characteristics are similar structures due to common ancestry, but due to different selection pressures and mutations have developed changes to these structures = homologous structures. This process is called adaptive radiation.

What is a viable gene pool?

A viable gene pool is a sustainable population capable of surviving selection pressures, as a result of its genetic biodiversity (able to adapt).

What are conservation plans to maintain viable gene pools?

• biogeography

• reproductive behaviour

• population dynamics

What are characteristics of a viable population?

• genetic diversity/alleles

• large numbers of breeding individuals

• large number of males and females

How does genetic diversity maintain a viable gene population?

Genetic diversity helps as some alleles exist that may provide selective advantage to new selection pressures.

How does large numbers of breeding individuals maintain a viable gene population?

Large number of breeding individuals helps as a large number of offspring is produced it keeps the population numbers stable and there is more variety in offspring, meaning less genetic drift.

What is tolerance limits?

Tolerance limits to a range of abiotic and biotic factors present. e.g. climate, predators, food web

What are factors that affect the reproductive behaviour of organisms?

• long breeding season

• reduced sexual selection

• increased reproductive capacity

• allow capacity for courtship behaviour

• allow for increased parental care