Bio A 351 Exam 2

Nausea and Vomiting of Pregnancy (NVP)

Nausea and vomiting experienced during pregnancy, often called morning sickness.

Maternal and Embryo Protection Hypothesis

The hypothesis that NVP helps protect the mother and embryo from harmful pathogens and dietary toxins.

Organogenesis

The period of embryonic development when major organs are forming.

Secondary Compounds

Chemicals produced by plants that help protect them against herbivores.

Smoke Detector Principle

A defensive response may be favored despite false alarms when missing a real threat is much more costly.

Food Aversion

Avoidance of particular foods, potentially reducing exposure to harmful toxins or pathogens.

Kin Selection

Natural selection that favors behaviors benefiting genetic relatives.

Inclusive Fitness

An individual's genetic success through personal reproduction and helping relatives reproduce.

Hamilton's Rule

Kin selection is favored when R × B > C.

Relatedness (R)

The proportion of genes shared between individuals due to common ancestry.

Benefit (B) in Hamilton's Rule

The reproductive benefit received by the individual helped.

Cost (C) in Hamilton's Rule

The reproductive cost experienced by the individual performing the behavior.

Parent-Offspring Conflict

Conflict arising because parents and offspring have partly different evolutionary interests.

Maternal Evolutionary Interests

Mothers may favor distributing resources among current and future offspring.

Paternal Evolutionary Interests

Paternally inherited genes may favor greater investment in the current offspring.

Genomic Imprinting

Parent-of-origin-dependent gene expression in which one inherited gene copy may be silenced.

IGF-II

A paternally expressed growth factor that promotes placental growth and cell division.

Why is IGF-II an example of parent-offspring conflict?

It promotes fetal growth and greater use of maternal resources, reflecting paternal genetic interests.

Why is genomic imprinting less likely in most frogs?

External fertilization and resource allocation before fertilization reduce opportunities for paternal genes to influence maternal investment.

Evolutionary Mismatch

A situation in which evolved traits are poorly suited to a changed environment.

Diseases of Affluence

Health problems associated with excessive exposure to stimuli or resources that were less common ancestrally.

Diseases of Disuse

Health problems associated with insufficient exposure to environmental stimuli the body evolved to require.

Phenotypic Plasticity

The ability of an organism to change measurable characteristics in response to environmental conditions.

Antifragility

The ability to improve or become stronger through appropriate stress.

Fragility

A tendency to break down or deteriorate when exposed to stress.

Robustness

The ability to resist stress or withstand disturbances without breaking down.

Safety Factor

Extra structural capacity beyond what is normally required for a task.

Why doesn't the human body have unlimited safety factors?

Building and maintaining additional capacity requires energy and can create other functional costs.

No Strain, No Gain

Muscles, bones, and other systems need appropriate stress or stimulation to develop and maintain capacity.

Hygiene Hypothesis

Reduced exposure to microorganisms during development may contribute to inappropriate immune responses.

Old Friends Hypothesis

Exposure to certain coevolved microorganisms and parasites may help regulate immune-system development.

How did farming affect infectious disease?

Larger settlements, closer animal contact, and denser populations increased opportunities for pathogen transmission.

How can softer diets affect jaw development?

Reduced chewing and mechanical loading may decrease stimulation of jaw development.

Acute Stress

A short-term response that can increase alertness and activate fight-or-flight responses.

Chronic Stress

Prolonged stress-response activation that can contribute to harmful health effects.

Cortisol

A hormone that helps the body adjust priorities and allocate energy in response to challenges.

How can cortisol be beneficial?

It increases energy available to deal with immediate stressors.

What are potential costs of chronically elevated cortisol?

Suppressed immunity, growth, reproductive function, and tissue repair.

Antagonistic Pleiotropy

A trait that provides benefits earlier in life but causes costs later in life.

Gene-Environment Mismatch in Stress

Stress responses adapted for particular ancestral challenges can become harmful when activated chronically in modern environments.

Hagen's Hypothesis of Depression

Depression may signal need, encourage paternal investment, or help mothers stop investing in offspring unlikely to survive.

Depression as a Signal

Depressive symptoms may communicate distress or a need for assistance from others.

Why might reported depression increase?

Reduced stigma, better recognition, more reporting, changing populations, social isolation, social media, and COVID-19.

Why are depression rates difficult to compare across cultures?

Cultures differ in how psychological distress is understood, expressed, and reported.

Naturalistic Fallacy

The mistaken belief that something is morally good or acceptable simply because it occurs in nature.

Double Jeopardy Hypothesis (DJH)

The hypothesis that racism and sexism can combine so subordinate-group women experience compounded disadvantage.

Evidence discussed against Double Jeopardy

Some studies found that people facing multiple marginalized identities did not report more discrimination than those facing one.

Subordinate Male Target Hypothesis (SMTH)

The hypothesis that subordinate-group males may be especially targeted by dominant-group males.

How can racial discrimination affect health?

It can increase stress and expose people to unequal risks in housing, pedestrian safety, and police interactions.

Racial Bias at Crosswalks

A study found Black pedestrians were passed by twice as many cars and waited 32% longer than matched white pedestrians.

Housing Discrimination

Unequal treatment in housing, including differences in rent quotes, move-in specials, and screening criteria.

Cortisol and Life-History Trade-Offs

Cortisol reallocates energy toward immediate challenges at the expense of functions such as immunity, growth, reproduction, and tissue repair.

Sexual Selection

Natural selection arising from differences in mating success.

Bateman's Principle

Male reproductive success is generally more dependent on the number of mates than female reproductive success.

Sexual Dimorphism

Physical differences between males and females of the same species.

Polygyny

A mating system in which one male mates with multiple females.

Elephant Seals and Sexual Selection

Elephant seals illustrate intense male-male competition, polygyny, and substantial sexual size dimorphism.

Human Sexual Dimorphism

Humans show sex differences in traits including lean mass, but relatively modest overall body-size differences compared with some other apes.

Human Lean Mass Difference

Lecture material described men as having approximately 30% greater lean mass than women on average.

Proposed Explanation for Reduced Human Body-Size Dimorphism

Bipedalism and opposable thumbs may have reduced the need for extreme male body-size advantages in physical competition.

Fragile Male Hypothesis

Male reproductive strategies and competition may contribute to greater male mortality and reduced investment in long-term survival.

Allocation Rule

Organisms have finite resources that must be divided among growth, maintenance, activity, storage, and reproduction.

Life-History Trade-Off

Investment in one function can reduce the resources available for another because time and energy are limited.

Why might male mortality be higher?

Reproductive competition, risk-taking, and investment in growth and mating effort may come at the expense of survival and maintenance.

External Causes of Death

Causes such as accidents and violence, which the lecture noted are significantly higher among males in some populations.

Sexual Selection and Male Risk-Taking

Competition for mates may favor risky behaviors that increase reproductive opportunities but also increase mortality.

Alcohol Metabolism Hypothesis

A proposed explanation that an ancient mutation improved alcohol metabolism in ancestors consuming fermented fruit.

Fermented Fruit

Fruit containing alcohol produced by natural fermentation.

Alcohol and Evolutionary Mismatch

A possible ancestral ability to consume fermented fruit may have harmful consequences in environments with readily available concentrated alcohol.

Social Drinking

Alcohol consumption in social settings, which the assigned reading discusses in relation to social interaction and bonding.

Solitary Drinking

Alcohol consumption alone, discussed in the reading in relation to negative emotional states and coping.

Worms and Immune Regulation

Some coevolved parasites may have influenced immune-system regulation, as discussed in relation to the old friends hypothesis.

Sickle-Cell Trait and Malaria

Heterozygotes for the sickle-cell allele have increased resistance to malaria.

Balancing Selection

Selection that maintains multiple genetic variants in a population because different variants or genotypes have different fitness advantages.

Sickle-Cell Anemia

A serious condition that can occur in individuals homozygous for the sickle-cell allele.

Why did malaria increase selection for the sickle-cell allele?

Malaria created a survival advantage for heterozygotes carrying the allele.

Expensive Tissue Hypothesis

The hypothesis that the energetic costs of a large brain were offset partly by reduced investment in other costly tissues, especially the gut.

Why are animal foods relevant to human brain evolution?

Energy-rich foods, including meat and marrow, may have helped support the high energetic costs of larger brains.

Proximate Explanation

An explanation describing the immediate biological mechanism behind a trait or process.

Ultimate Explanation

An explanation describing the evolutionary reason a trait or process may have been favored or maintained.

Vitamin C Synthesis in Humans

Humans lost the ability to synthesize vitamin C, discussed in relation to ancestral diets rich in fruit.

Natural Selection

A process in which heritable traits associated with greater reproductive success become more common.

Evolution

Change in inherited characteristics or allele frequencies in populations across generations.

Phenotype

Measurable characteristics of an organism, including physical traits and behaviors.

Genetic Variation and Fitness

Genetic variation does not always produce phenotypic variation or differences in fitness.