Competition Flashcards
Who proposed exponential population growth and what does it mean?
Thomas Malthus proposed the theory. It means that population growth rate stays the same regardless of population size.
Define ‘competition’.
Differential reproductive success
Describe ‘fitness’ and the process of natural selection.
Fitness refers to the number of copies in the next generation that a copy in this generation leaves (the change in frequency of alleles over generations). Natural selection changes allele frequencies and increases the frequency of alleles that have the highest fitness and decreases the frequency of those that have the lowest fitness.
What does evolution favour?
Evolution favours whatever helps reproduction, not what is good for the species.
What is adaptive evolutionary change? Give an example.
It is the consequence of an allele defeating another in completion in the gene pool of a population. For example, allele X increases height - the phenotypes X appears on will be taller than those it does not appear on - if height is advantageous, X will gradually increase in frequency - the average height of the population will increase.
Define the evolutionary stable strategy using an example.
The evolutionary stable strategy suggests that once a behaviour is common in the population, it cannot be outcompeted by a different behaviour. E.g. infanticide is a major cause of death for lion cubs, which is bad for the species. But it has evolved because alleles of committing infanticide can outcompete those for not committing infanticide.
What is ‘kin selection’?
Adaptions that are better for the group rather than the individual are likely to be outcompeted. We expect organisms to be designed in a way that promotes individual interests.
Give an animal example of inclusive fitness.
Some birds have the mutant a1 allele which makes the younger sisters help the reproduction of the older sister. The competitor allele is a2 which causes the younger sister to reproduce for themselves. a1 outcompetes a2 because by helping the older sisters, bearers of a1 are helping other copies of a1 reproduce.
What is Hamilton’s rule?
Hamilton’s rule states that a trait is favoured by natural selection when the benefit to others (B), multiplied by the relatedness (R) is greater than the cost to self (C). C
What are the 2 conditions of Hamilton’s rule?
Rule 1 = behaviour won’t evolve if C is too large. The rule can only be applied to behaviours with a weaker selective disadvantage. Rule 2 = the coefficient of relatedness isn’t sufficient to predict which behaviours will evolve. B is variable depending on the future prospects of the recipient and actor respectively.
List the four concepts explained by kin selection.
Alloparenting, kin-directed helping, mutil-cellularity, and eusociality
Define multi-cellularity using an example.
99% of cells don’t reproduce, they help eggs/sperm to do reproduction. E.g. the R between liver and sperm is 1, so it is just as good to help the sperm reproduce.
Describe the process of evolutionary transitions.
- Molecules left copies of each other
- These turned into molecules bound together
- Caused replication of the whole cell
- Turned into normal cell containing mitochondria
- Developed multi-cell organisms
- These changed into eusocial colonies where everything helps one thing reproduce
What is cytoplasmic male sterility in plants?
Mitochondrial genomes are only inhereted down the female line which causes conflict between the mitochondrial genome and the genome of the cell nucleus. The nucleus only succeeds in female offspring, the mitochondrial genome will succeed in either sex. Any mutations in the mitochondrial genome that increase the proportion of females will have a selective advantage over competitors.
