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EVOLUTION, HEREDITY, AND BEHAVIOR

EVOLUTION, HEREDITY, AND BEHAVIOR. TO MAN. FROM MONKEY. DARWIN AND EVOLUTION. Biological evolution- changes that take place in the genetic and physical characteristics of a population overtime

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EVOLUTION, HEREDITY, AND BEHAVIOR

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  1. EVOLUTION, HEREDITY, AND BEHAVIOR

  2. TO MAN FROM MONKEY

  3. DARWIN AND EVOLUTION • Biological evolution- changes that take place in the genetic and physical characteristics of a population overtime • Adaptive significance-Its effectiveness in aiding the organism to adapt to changing environmental conditions (Ex.-gregariousness-tendency to form groups) • Ultimate causes-Events and conditions over successive generations that have slowly shaped the behavior of our species • Proximate causes-Immediate environmental variables that affect behavior • Artificial selection-A procedure in which particular animals are mated to produce offspring who possess desirable characteristics. • Natural selection-Competition amongst animals, those with best-adapted traits survive

  4. Evolutionary Psychology • Investigates how an organism’s evolutionary history contributes to the development of behavior patterns and cognitive strategies related to reproduction and survival in its lifetime • May help psychologists understand how evolution and development influence culture (sum of socially transmitted knowledge, customs, and behavior patterns common to a particular group)

  5. Natural Selection and Evolution – Premises for Evolution • The world’s animal & plant communities change over time with new forms originating and others becoming extinct • Evolutionary process is gradual and continual. New species arise through slow and steady environmental changes that gradually ‘perfect’ each species to its surroundings. Sudden, dramatic changes in environment challenges species ability to adapt. • All organisms descended from an original & common ancestor.Over time, the process of natural selection has created different species, each adapted to its ecological niche

  6. AND FINALLY… 4. Natural selection not only causes changes within a population during changing environmental conditions; it also maintains the status quo under relatively constant environmental conditions.

  7. REPRODUCTIVE SUCCESS The number of viable offspring it produces relative to the number of viable offspring produced by other members of the species ***Survival of the fittest does NOT always mean survival of the most physically fit or strongest, but depends on reproductive success

  8. Two Aspects of Natural Selection • Variation-Differences among members of a species Genotype-genetic make-up,everyone’s different.determines how much environment can influence development and behavior Phenotype-Characteristics and behaviors produced by interaction of genotype in environment (intelligence) FACTORS

  9. Competition-Organisms will compete for food, territory, and mates to survive

  10. Natural Selection in Human Evolution • Gorillas and Chimps-closest living relative • Human species began 2 million years ago • Homo-habilis “handyman”-1st human,1.3meters tall,40kg,could walk upright and make tools

  11. Homo-erectus “upright man”-larger brain, discovered fire, made base campsHOMO-SAPIENS “INTELLIGENT MAN”500,000 years ago,skilled toolmakers and clothiers, had cultural rituals,used fire for cooking, warmth and protection

  12. Natural Selection Favored 2 characteristics • Bipedalism-walking on 2 feet,greater mobility • Encephalization-Increased brain size>thinking,reasoning,decision making,greater reproductive success

  13. HEREDITY AND GENETICS • Genetics-The study of the structure and function of genes and how they are passed along from one generation to the next,how genetic makeup influences physical and behavioral characteristics • Heredity-sum of traits and tendencies inherited from parents and other ancestors

  14. Basic Principles of Genetics • DNA(deoxyribonucleic acid)-strands of sugar and phosphate connected by nucleotide molecules of adenine,thymine,guanine,&cytosine • Genes- ‘Recipes for Protein Synthesis’ Each nucleotide specifies and particular amino acid that has instructions for synthesization,causing trait to appear<faulty genes can cause serious physiological and behavioral problems>

  15. Chromosomes and Meiosis • Genes are located on chromosomes-rod-like structures made of DNA found in the nucleus of every cell • Each set contains a different sequence of genes (23 from each parent) • Sex Chromosomes-contain instructions for development of male or female characteristics

  16. SEX SELLS (I MEAN CELLS) form through MEIOSIS • 23 pairs of chromosomes break apart into 2 groups, one member of each pair joining a group. • The cell splits into 2 cells, each containing 23 indiv. Chromosomes • The assignment of members of each chromosome is random • A SINGLE individual can produce 8,388,608 different ova or sperm • Union of ova and sperm also random, a couple can produce 70,368,774,177,664 different children • 23rd pair-sex chromosomes XX-female, XY-male, sperm determines sex.

  17. DOMINANT AND RECESSIVE ALLELES • Allele-alternative forms of the same gene • Homozygous-both parents contribute same allele • Heterozygous-parents contribute different alleles • Dominant allele-more powerful influence on expression of trait • Recessive allele-not expressed unless both alleles are recessive

  18. Influences of Gender on Heredity • Sex-linked genes-only carried on X chromosome Ex)hemophelia-carried as recessive gene only on X, females need both recessive chromosomes to inherit it and males only need one

  19. Mutations and Chromosomal Aberrations • Mutation-accidental alteration to DNA code within a single gene *original source of genetic diversity *most harmful, though some beneficial *can occur naturally or because of human factors (radiation) • Chromosomal aberration-changes in parts of chromosomes or total # of chromosomes *Ex)Partial deletion of chromosome 5 causes cri-du-chat

  20. Genetic Disorders • Down Syndrome-Chromosomal aberration-extra chromosome 21 *15% die before 1st b-day *> chance, the older the mother is *Not hereditary • Huntington’s Chorea-caused by dominate lethal gene, results in degeneration of certain parts of the brains *Emerges between ages 30 and 40

  21. Genetic Disorders (cont.) • Phenylketonuria(PKU)-caused by a homozygous recessive gene. They are unable to breakdown phenylalanine. *High levels of phenylalanine in blood causes severe brain damage and mental retardation. *Infants routinely tested

  22. Genetic Counseling • The process of determining the likelihood that a couple may produce a child having a genetic disorder *pedigree analysis to identify relatives with genetic disorders *Amniocentesis-fetus can be tested for genetic disorders by removing and examining fetal cells in amniotic fluid

  23. Heredity and Behavior Genetics • Heritability-Statistical term that refers to the amount of variability in a trait in a given population, not inheritance • Behavior Genetics-Scientific study of heritability of the effects of genetic influence on behavior

  24. Studying Genetic Influence using Artificial Selection • Any heritable trait can be selected in a breeding program Ex)aggression, preference for alcohol,mating behaviors • Bred smart mice together-had smart babies, however environment does affect expression of genetic traits

  25. Twin Studies and Genetic Influence • Most powerful weapon in study of human genetics • Unethical to manipulate people’s genetic history or restricting environment • Monozygotic-single fertilized ovum • Dizygotic-fertilization of 2 separate ova

  26. Twin Studies and Concordance Research • Examines degree of similarity in traits expressed between twins • If one observes High concordance in MZ twins & low in DZ twins can conclude it’s genetic *Concluded genetics affect language, math, and vocabulary skills, personality traits, emotional stability, and psychological disorders *Blood type 100% heritability

  27. Strategies for Mating and Rearing Offspring • Monogamy-mating of 1 Female and 1 male (most popular not most practiced) • Polygyny-1 male mating with >1 female (most common) • Polyandry-1 female >1 male (rare) • Polygynandry-Many males and many females (Chimps)

  28. Parental Investment • Time, Phys. Effort, and risks to life involved in procreation and in feeding, nurturing and protecting offspring *critical factor in mate selection *one willing to have greater investment is a more sought after mate • Competition for mates leads to Sexual selection-selection for traits specific to sex such as body size or behavior

  29. Biological Basis for Altruism • Altruism-unselfish concern of one indiv. For the welfare of another • Kin selection-biological favoritism towards relatives • Inclusive fitness-Reproductive success of those who share same genes *Indiv. Behave altruistically towards those that share genetic history, and relatives survive

  30. AND… • Reciprocal altruism-Behaving altruistically towards someone because you believe the act will be reciprocated to you or your kin

  31. THAT’SALLFOLKS

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