EXAM 3 4/1 Flashcards
Does mating between closely related relatives increase the likelihood of inheriting (dominant or recessive) deleterious genes?
recessive deleterious because they are usually only expressed when both parents have them
What is more likely to be selected out of the population over time: dominant or recessive genes?
recessive
inbreeding
Occurs when closely related individuals mate, increasing the likelihood of genetic disorders and defects due to the expression of harmful recessive traits. This was seen in royalty in england and egyptians
inbreeding depression
The reduction in the fitness and survival of offspring resulting from mating between closely related individuals. (accumulation of deleterious recessive genes)
consequences of inbreeding
reduced genetic diversity in the population. Populations with little genetic variation are more susceptible to diseases and environmental changes.
Are mates only chosen by similarity to biological parents?
No, many animals learn to bond with individuals they are raised with, not necessarily with their biological parents. This learned preference helps form attachments that are not based on genetics. ex: siblings, grandparents
Animals typically mate with people who are similar to those that they grew up around. What species is the exception?
brood parasites demonstrate that some species can select mates based on strong genetic predispositions rather than early life exposure.
Experiment with choosing faces. What did humans and animals pick?
faces that look similar to what they grew up with
people who lived in what kind of area were more likely to marry those within their close genetic circle
rural areas due to limited exposure to outsiders. Urbanization and modern mobility have reduced the likelihood of close-kin marriages in contemporary society.
what is the genetic benefit to inbreeding
The “genetic benefit” of mating with someone genetically similar (such as a cousin) is that more than 50% of genetic material is passed on. this is why there needs to be a balance of similar but not too similar to prevent defects but also maximize passing on genetic material
hybrid vigor pros and cons
increased fitness of offspring produced by mating genetically diverse individuals. This leads to healthier offspring but also can create mismatched traits in offspring (negative). Mismatched traits are traits that are beneficial in one environment that become detrimental in another, or where traits within a population become too varied to function cohesively
How does picking a mate with a similar scent to close family members avoid inbreeding
This preference for familiar odors may be a subtle mechanism for avoiding inbreeding. Scent may also be linked to social characteristics such as political preferences or other personality traits. People tend to prefer scents from those with similar political opinions.
what can affect the sex of offspring
High-ranking females tend to have more male offspring, while low-ranking females may have more female offspring.
In stressful conditions or times of food scarcity: female (also r strategy during stress)
During good times with abundant resources: male
In some species, the timing of intercourse relative to ovulation can influence whether the offspring will be male or female.
temperature of the testes: warm male and cold female
In a lab you can pick the gender
What increases sperm count and induces ovulation?
foreplay
why is the average number of sperm per ejaculation decreasing as time goes on?
it has reduced 40% in the last 50 years this may be due to an exposure to female hormones in livestock and food; sperm count is higher in third world countries where livestock is not treated with hormones; microplastics can cause reduced sperm count and higher miscarriage rates
what happens is sperm count keeps decreasing over the years
If the current trend continues, it could significantly impact reproductive health in future generations, potentially requiring assisted reproductive technologies for conception.
do all animals follow the same reproductive patterns or behaviors
no, there are individual differences that lead to a range of outcomes, some may deviate from the norm significantly
what gender sperm are better at reaching the egg in a 24 hour time frame of ovulation
males but a day and a half after ovulation, females because the male sperm has died
