ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 ANTH 1001 Irrelevant Fact of the Day Hippos secrete a red orange liquid that acts as sunscreen blocking ultraviolet radiation 1 2 Announcements Reminders Labs start this week Remember to bring your lab manual You will work on Lab 1 during the in person lab section Pre lab quiz 2 is due this Sunday Sept 17 at 11 59 pm We are searching for a peer note taker 1 Image Science Pusheen 2 UMN Twin Cities Campus 1 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Review Human biocultural traits Human diversity What is evolution Introduction to Darwin s ideas about natural selection 3 4 3 ANTH 1001 HUMAN EVOLUTION MECHANISMS OF EVOLUTION I Maria Nieves Col n Gilbert Tostevin Department of Anthropology University of Minnesota 4 UMN Twin Cities Campus 2 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 What do we mean by evolution Evolution change in the heritable characteristics of biological populations Hamadryas baboon over successive generations Evolution occurs at the population level over time Traits vary between individuals but only populations evolve Human Image BioNinja 5 Source Halszka Golwacka Ask an Anthropologist Evolution by natural selection Natural selection is differential reproductive success based on variations in heritable traits Darwin and Wallace observed that some traits help organisms survive and or reproduce better than individuals who lack those features Those organisms will produce more offspring Thus beneficial features are passed on to offspring in greater proportion and become more frequent in the population Over time this can lead to radical changes in the species 6 Hamadryas baboon 5 6 Human Image istock UMN Twin Cities Campus 3 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Evolution Descent with modification Evolution Descent with modification 7 7 8 Images http evolution berkeley edu evosite 8 UMN Twin Cities Campus 4 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Three conditions for natural selection 1 Variation in a trait 2 Inheritance of the trait 3 Variants of the trait cause differential reproductive success Image BioNinja 9 Adaptation a change that allows an organism to survive in a given environment Species change and adapt depending on their environmental context with no pre determined goal or direction 10 Natural selection is NOT goal oriented 9 10 UMN Twin Cities Campus 5 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 ChimeIn Which of the following images depicts evolution Login to Canvas and click on the In Lecture Chime In link on the course homepage Load ChimeIn questions in a new window ANTH 1001 Fall 2023 Select your response 11 11 12 What Darwin and Wallace didn t know A major criticism of Darwin and Wallace s idea of evolution by natural selection was that at the time the exact mechanisms of inheritance were not yet known People were asking How is the variation on which evolution works inherited How are traits passed on from generation to generation UMN Twin Cities Campus 12 6 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 On genetics and inheritance Gregor Mendel 14 Where is DNA found in the cell This is us We have nucleus Bacteria not us 14 15 UMN Twin Cities Campus 7 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Where is DNA found in the eukaryotic cell Mitochondrial DNA mtDNA Nuclear DNA We are eukaryotes Almost all our cells have two kinds of DNA 16 17 Genetic organization from mom from dad Chromosomes discrete structures containing nuclear DNA 23 pairs 46 in humans Homologous chromosomes carry information for the same traits 1 from father 1 from mother Diploid full complement of chromosomes found in somatic cells Haploid half set of chromosomes found in gametes UMN Twin Cities Campus 17 8 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Somatic vs gametic Somatic cell The cells that make up your bodily tissues soma Each diploid somatic cell carries two copies of your genome Somatic vs gametic Gametic cell Your reproductive cells in humans sperm or eggs Each haploid gametic cell carries one copy of your genome 18 19 18 19 UMN Twin Cities Campus 9 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Structure of DNA DNA molecule is composed of two chains of nucleotides Nucleotide phosphate sugar base Bases adenine A thymine T cytosine C guanine G A T C G chain attached DNA chain is built with a complimentary Twists to form a double helix 20 21 P S B Nucleotide Phosphate P S B Sugar Base Nucleotides link into chains to form a single strand of DNA Phosphate sugar backbone provides structure for the molecule Bases A T C G are the units of genetic information P P P P P P S S S S S S B B B B B B UMN Twin Cities Campus 20 21 10 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Structure of DNA 2 complimentary strands of DNA join at the bases to form the DNA double stranded DNA molecule Electro chemical properties of the molecule cause it to twist into a double helix P P P P P P S S S S S S A A G T C G P P P P P P 22 S S S S S S T T C A G C 22 23 Two functions of DNA 1 Replication Double strand unzips between bases Complimentary nucleotides attach to the free bases Original strands eventually separate completely each component strand having a new complimentary strand Afterward enzymes proofread the new strands there is an error rate of about 1 mistake per billion base pairs Human genome has about 3 billion base pairs https commons wikimedia org wiki File DNA replication split sv g 23 UMN Twin Cities Campus 11 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Mitosis cell division duplication for growth and repair cell division for somatic cells diploid condition is retained full complement of results in two identical daughter cells chromosomes only one chromosomal pair shown here https commons wikimedia org wiki File Mitosis 261 14 Pressed root meristem of onion cells in prophase anaphase jpg Meiosis cell division for gamete production 25 26 sex cells require only half the number of chromosomes results in four daughter cells For males all continue to become sperm For females one of the four continues to becomes an ovum gametes are haploid only one chromosome from each parent is passed on to the offspring UMN Twin Cities Campus 12 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Variation arises during DNA replication Occurs when homologous chromosomes crossover and exchange genetic
View Full Document
Unlocking...