Transcript EVOLUTION, HEREDITY, AND BEHAVIOR

EVOLUTION,
HEREDITY,
AND
BEHAVIOR
FROM
MONKEY
TO MAN
DARWIN AND EVOLUTION
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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
Evolutionary Psychology
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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)
Natural Selection and Evolution
– Premises for Evolution
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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
AND FINALLY…
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Natural selection not only causes
changes within a population during
changing environmental conditions; it
also maintains the status quo under
relatively constant environmental
conditions.
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
Two Aspects of Natural
Selection
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Variation-Differences among members of
a species
FACTORS
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)
Competition-Organisms will
compete for food, territory, and
mates to survive
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
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Homo-erectus “upright man”-larger brain,
discovered fire, made base camps
HOMO-SAPIENS “INTELLIGENT
MAN”
500,000 years ago,skilled toolmakers and
clothiers, had cultural rituals,used fire for
cooking, warmth and protection
Natural Selection Favored 2
characteristics
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Bipedalism-walking on 2 feet,greater
mobility
Encephalization-Increased brain
size>thinking,reasoning,decision
making,greater reproductive success
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
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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>
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Chromosomes and Meiosis
Genes are located on chromosomesrod-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
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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, XYmale, sperm determines sex.
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DOMINANT AND RECESSIVE
ALLELES
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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
Influences of Gender on
Heredity
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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
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
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Genetic Disorders
Down Syndrome-Chromosomal aberrationextra 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
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Genetic Disorders (cont.)
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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
Genetic Counseling
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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
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
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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
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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
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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
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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)
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Parental Investment
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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 selectionselection for traits specific to sex such as body size or
behavior
Biological Basis for Altruism
Altruism-unselfish concern of one indiv. For
the welfare of another
 Kin selection-biological favoritism towards
relatives
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Inclusive fitness-Reproductive success of those
who share same genes
*Indiv. Behave altruistically towards those that share
genetic history, and relatives survive
AND…
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Reciprocal altruism-Behaving
altruistically towards someone because
you believe the act will be reciprocated
to you or your kin
THAT’S
ALL
FOLKS