Lecture 15 Exam 2 Review PDF

Exam 2 Review Lecture 15 Announcements Tuesday, 11/5 – No class, GO VOTE Friday, 11/8 – EXAM 2 Tuesday, 11/12 – Bring laptop You can borrow one from the library: https://library.hunter.cuny.edu/laptop-loan- policies Lecture 14 Terms and Concepts to Know Non-shivering thermo...

Exam 2 Review Lecture 15 Announcements Tuesday, 11/5 – No class, GO VOTE Friday, 11/8 – EXAM 2 Tuesday, 11/12 – Bring laptop You can borrow one from the library: https://library.hunter.cuny.edu/laptop-loan- policies Lecture 14 Terms and Concepts to Know Non-shivering thermogenesis Brown adipose tissue Allostatic responses to cold stress Examples of acclimatization to cold stress Genetic adaptations to cold stress Allostatic responses to heat stress Examples of acclimatization to heat stress Health consequences of warming climate Allostatic Responses to Cold Stress 1. Shivering 2. Non-shivering thermogenesis Heat that is produced through biological mechanisms that are separate from muscle twitching (shivering) 3. Vasoconstriction Allostatic Responses to Heat Stress Increase in sweat production Vasodilation Increase in heart rate Increase in blood viscosity Acclimatization to Heat Stress Lecture 14 Terms and Concepts to Know Non-shivering thermogenesis Brown adipose tissue Allostatic responses to cold stress Examples of acclimatization to cold stress Genetic adaptations to cold stress Allostatic responses to heat stress Examples of acclimatization to heat stress Health consequences of warming climate  Acclimatization and Evolutionary Mismatch How does this lecture material connect to the evolutionary mismatch hypothesis? In our evolutionary past, humans were more likely to exhibit acclimatization to heat and/or cold stress Less acclimatization today People that are acclimatized to heat stress have a lower risk of heat exhaustion and heat stroke People that are acclimatized to cold stress are less likely to experience a heart attack or stroke during a cold spell Less acclimatization -> higher risk of heat/cold- related illness Lecture 13 Terms and Concepts to Know Evolutionary arms race Morbidity Mortality Epidemiological transition Critiques of the concept 3 examples across human history and their contributing factors One Health Lecture 12 Terms and Concepts to Know Evolutionary mismatch Physical activity pattern of… Human-chimp LCA Homo erectus Fast-twitch muscle Slow-twitch muscle Persistence/endurance hunting Human adaptations to long-distance running Human adaptations to periodic famine Health benefits of exercise Additive Model of TEE Constrained Model of TEE Adaptive thermogenesis Evolutionary perspectives for increasing exercise Lecture 11 Terms and Concepts to Know Cline Population substructure Selective sweep Polygenic adaptation Haplogroup Reference population How can genetic tests reinforce or undermine the idea that race is a genetically determined category? Lecture 10 Terms and Concepts to Know Cline Population substructure Selective sweep Polygenic adaptation Haplogroup Reference population How can genetic tests reinforce or undermine the idea that race is a genetically determined category? Terms and Concepts to Know Hominin Human-Chimp Last Common Ancestor Evolution of bipedalism and brain size When did Homo sapiens evolve? When did plant and animal domestication arise? Evolutionary mismatch hypothesis WEIRD (what does it stand for?) DALYs Main arguments of paper by Gurven and Lieberman (2020) Review Question The Constrained Total Energy Expenditure hypothesis proposes that increasing your exercise might not lead to weight loss because… A. The human desire to exercise is constrained B. The human foot is not adapted for exercise C. At high levels of physical activity, energy allocation toward other biological functions will decrease D. Exercise is not good for your health First Transition Lower infectious disease burden during the Paleolithic Early hominids groups were too small and too dispersed to pass on many pathogens Long-standing hominid-parasite relationships Many parasite species that are common among humans and non-human primates Second Transition Coincided with the industrial revolution in mid-19th century in Europe and N. America Decline in infectious disease mortality *caused an increase in life expectancy Contributing factors Improved nutrition Pasteurization Public health care Home-based primary health care Vaccinations Antibiotics Second Transition Increased morbidity from chronic disease Cancer, diabetes, heart disease, autoimmune disorders Contributing factors Air and water pollution Urbanization Associated with increased hypertension, depression, anxiety Mass produced processed foods Sedentary lifestyles Third Transition Contributing factors Globalization Ecological disruption Climate change Habitat destruction Antimicrobial resistance Factory farming One Health “Human or livestock or wildlife health can’t be discussed in isolation anymore. There is just one health” – William Karesh Aim Improve health and wellbeing through prevention/mitigation of crises that originate at the interface of humans, animals and their environments Emphasis on collaboration  One Health From: http://www.onehealthinitiative.com/about.php WEIRD Bodies Disability-adjusted life years (DALYs) Reflect the total number of years lost due to illness, disability and premature death Combines the effects of morbidity and mortality Main messages of Gurven and Liberman (2020) The way populations in WEIRD countries use their bodies is different from humans in our evolutionary past The way populations in WEIRD countries use their bodies is different from contemporary populations in non-WEIRD countries We need to understand the full spectrum of human biological variation and its origins if we’re going to improve human health  Epidemiological Transition A model for integrating epidemiological and demographic changes in human populations Based on the observation that… Nations that experience a decline in infectious disease mortality exhibit An increase in life expectancy An increase in chronic disease morbidity Epidemiological Transition Critiques of the concept Use of whole nations as a unit of analysis Obscures variation within nations Dual burden in middle-income countries Increasing rates of chronic disease Persistence of high infectious disease mortality The Constrained TEE Hypothesis Adaptive thermogenesis When metabolic rate is lower than expected after a person consumes a meal Pattern detected in some individuals in response to dieting (i.e. negative energy balance) WEIRD Bodies Western Educated Industrialized Rich Democratic (WEIRD) "Medical science's understanding of human health and disease relies heavily on people of European descent living in a contemporary urban, industrialized environment" Gurven, M. D., & Lieberman, D. E. (2020). WEIRD bodies: mismatch, medicine and missing diversity. Evolution and Human Behavior, 41(5), 330- 340. How has natural selection shaped the human genome? Selective sweep When a beneficial novel mutation increases in frequency in a population through natural selection Hard selective sweep model Humans migrate into new environments -> strong selection for novel beneficial mutations Polygenic adaptation Natural selection for multiple alleles that already existed in the population Each allele has a small effect on the adaptive phenotype A faster mode of adaptation **Most human genetic adaptations are polygenic adaptations What is the Paleolithic? Period that begins with hominins beginning to use stone tools ~3.3 million years ago Ends with the last glacial period (c 11,650 BP) Sedentary Lifestyles as an Evolutionary Mismatch What do we know about physical activity across our evolutionary ancestors? Last common ancestor (LCA) between humans and chimps had many chimp-like characteristics Chimp physical activity Twice as strong as humans Walk less than 1.5 miles/day Rarely sprint Leg muscles are mostly fast-twitch fibers Can’t cool effectively through sweating Sedentary Lifestyles as an Evolutionary Mismatch What do we know about physical activity across our evolutionary ancestors? Pronounced adaptations to bipedalism in Homo erectus Persistence hunting Sedentary Lifestyles as an Evolutionary Mismatch What do we know about physical activity across our evolutionary ancestors? Evidence to support that Homo erectus was using persistence hunting Expanded gluteus maximus Short toes Head stabilization for running  Sedentary Lifestyles as an Evolutionary Mismatch Humans evolved to be adapted for regular, modest amounts of endurance physical activity More slow-twitch muscle fibers Evolved efficient sweating for thermoregulation Large glutes  Sedentary Lifestyles as an Evolutionary Mismatch Humans also evolved to avoid unnecessary energy expenditure Evidence to support this interpretation Humans have a higher percent body fat than other primates Chimpanzee – 5-8% Hunter-gatherer males – 10-15% Hunter-gatherer females – 15-25% Adaptation to intermittent caloric scarcity  Sedentary Lifestyles as an Evolutionary Mismatch Humans also evolved to avoid unnecessary energy expenditure Evidence to support this interpretation Data from contemporary hunter-gatherers Often stay close to energy balance Periodic scarcity and abundance depending on the season  Sedentary Lifestyles as an Evolutionary Mismatch Humans also evolved to avoid unnecessary energy expenditure Evidence to support this interpretation Muscles consume ~40% of RMR Muscles hypertrophy or degenerate depending on use  Sedentary Lifestyles as an Evolutionary Mismatch Humans also evolved to avoid unnecessary energy expenditure Evidence to support this interpretation Muscles consume ~40% of RMR Muscles hypertrophy or degenerate depending on use Many other systems (i.e. circulatory, skeletal, nervous system) are activated during PA or degenerate under sedentary conditions Human settlements with plant and animal domestication arose 4,000-12,000 years ago in multiple locations Clines and Substructure Cline - frequency of variants (alleles or phenotypes) is high in some geographic regions and gradually becomes less frequent as one moves away from that region 39 Population Substructur e Clustering of allele frequencies within a cline due to non- random mating  How can genetic tests reinforce or undermine the idea that race is a genetically determined category? “Racial experience in the age of direct-to-consumer ancestry testing” How do genetic ancestry tests work? Compares test-taker’s haplogroups to the frequency of haplogroups in reference populations Haplogroup A group of similar haplotypes that share a common ancestor What haplogroups do you have? Which reference populations have a high frequency of your haplotypes? What is a reference population? Based on population substructure within a cline The genetic clustering in a reference population depends on which individuals are included in the database The Constrained TEE Hypothesis Additive Model of TEE TEE = BMR + PA + thermogenesis + immune function + digestion + reproduction, etc. The Constrained TEE Hypothesis TEE is constrained at high levels of physical activity Morbidity vs Mortality Morbidity = the rate of a disease in a population Mortality = the proportion of deaths in a population Health of Hunter-Gatherers Hunter-gatherer populations have low rates of chronic diseases such as Heart disease, hypertension, diabetes, cancer Expected Lifespan at Birth: 30-40 years old Due to high infant mortality from infectious disease Expected Lifespan at Age 15: 72 years old Critiques of the “Paleo Diet” There is no single Paleolithic diet Wide variation in macronutrient composition and plant- vs. animal-derived foods across populations The Consequences of Agriculture for Human Health Shift toward carbohydrate-based diet Skeletal signs of nutritional deficiencies in archaeological record Dramatic increases in population size Increase in infectious disease Greater inequality Variation in its affects due to differences in geography, politics, culture, and population size What is a Hominin? Hominoid (Apes) Us, our ancestors, great apes, lesser apes (gibbons, siamangs) Hominid (Great Apes) Us, our ancestors, great apes (chimps, gorilla, orangs) Hominin Us, our direct ancestors Dietary Adequacy Extent to which food intake fulfills one’s nutritional requirements Typically assessed using a 24 hour dietary recall Six broad categories of nutrients need to sustain life Macronutrients Carbohydrates Protein Micronutrients Fats Vitamins Minerals Water Fast-Twitch vs Slow-Twitch Muscle Fibers Fast twitch Slow twitch Can split ATP very More metabolically quickly efficient Rely on anaerobic Rely on aerobic metabolism metabolism Can contract at 2-3 Slower speed of times the rate as slow contraction twitch Greater endurance Good at generating than fast twitch short bursts of strength or speed  Because Homo sapiens evolved in Africa and stuck around for a over 100,000 years, most human genetic diversity evolved in Africa Genetic diversity outside of Africa is a subset of what exists within the continent due to founder effect and genetic drift 52 Why did hominins evolve bipedalism? Why did hominins evolve bipedalism?