Transcript evolution and speciation regents

EVOLUTION &
SPECIATION
VOCABULARY REVIEW


EVOLUTION – CHANGE OVER TIME
NATURAL SELECTION - INDIVIDUALS
BETTER ADAPTED TO THE
ENVIRONMENT ARE ABLE TO
SURVIVE & REPRODUCE.

A.K.A. “SURVIVAL OF THE FITTEST”
NEW VOCABULARY


POPULATION – GROUP OF
INDIVIDUALS OF SAME SPECIES
THAT INTERBREED
GENE POOL – COMMON GROUP OF
ALL GENES PRESENT IN A
POPULATION
Variation in Populations
2 processes can
lead to this:
Mutations change in DNA
sequence
Gene Shuffling –
from sexual
reproduction

Nonrandom mating: inbreeding and
assortive mating (both shift
frequencies of different genotypes)

Natural Selection:
differential
success in
reproduction;
only form of
microevolution
that adapts a
population to its
environment
Evolution of Populations
Occurs when there
is a change in
the types of
genes in a gene
pool
How natural selection works
Resistance to antibacterial soap
Generation 1: 1.00 not resistant
0.00 resistant
How natural selection works
Resistance to antibacterial soap
Generation 1: 1.00 not resistant
0.00 resistant
How natural selection works
Resistance to antibacterial soap
Generation 1: 1.00 not resistant
0.00 resistant
Generation 2: 0.96 not resistant
0.04 resistant
mutation!
How natural selection works
Resistance to antibacterial soap
Generation 1: 1.00 not resistant
0.00 resistant
Generation 2: 0.96 not resistant
0.04 resistant
Generation 3: 0.76 not resistant
0.24 resistant
How natural selection works
Resistance to antibacterial soap
Generation 1: 1.00 not resistant
0.00 resistant
Generation 2: 0.96 not resistant
0.04 resistant
Generation 3: 0.76 not resistant
0.24 resistant
Generation 4: 0.12 not resistant
0.88 resistant
Conditions needed for Genetic
Equilibrium
SPECIATION



THE FORMATION OF NEW SPECIES
AS NEW SPECIES EVOVLVE,
POPULATIONS BECOME
REPRODUCTIVELY ISOLATED
REPRODUCTIVE ISOLATION –
MEMEBERS OF 2 POPULATIONS
CANNOT INTERBREED & PRODUCE
FERTILE OFFSPRING.
3 ISOLATING MECHANISMS……..



BEHAVIORAL ISOLATION- CAPABLE OF
BREEDING BUT HAVE DIFFERENCES IN
COURTSHIP RITUALS (EX.
MEADOWLARKS)
GEOGRAPHICAL ISOLATION –
SEPARATED BY GEOGRAPHIC BARRIERS
LIKE RIVERS, MOUNTAINS, OR BODIES
OF WATER (EX. SQUIRREL)
TEMPORAL ISOLATION – 2 OR MORE
SPECIES REPRODUCE AT DIFFERENT
TIMES.
Tigon
Result of male tiger
and female lion
mating in captivity.
Offspring are infertile.
Separated both
geographically and
ecologically.
Liger
Result of male lion and female
tiger mating in captivity.
Offspring are infertile.
SPECIATION IN DARWIN’S
FINCHES

SPECIAITON IN THE GALAPAGOS
FINCHES OCCURRED BY:
- FOUNDING OF A NEW POPULATION,
- GEOGRAPHIC ISOLATION which led to - REPRODUCTIVE ISOLATION and
CHANGES IN THE NEW POPULATION’S
GENE POOL due to COMPETITION.
Big Question!!!
How did life arise on the big blue planet??
 Scientists attempt to answer this
question scientifically.
Big Bang Theory
 A cosmic explosion that hurled matter and in all
directions created the universe 10-20 billion years
ago
 Evidence
 it explains why distant galaxies are traveling
away from us at great speeds
 Cosmic radiation from the explosion can be
observed
 The Big Bang theory probably will never be
proven; consequentially, leaving a number of tough,
unanswered questions.
What was early earth like?
Earth was Hot!!
Little or no oxygen
Gasses in atmosphere:
Hydrogen cyanide (poison to you!)
Hydrogen sulfide
Carbon dioxide
Carbon monoxide
Nitrogen
So how did the earth
get oxygen?
 Some of that oxygen was generated by
photosynthetic cyanobacteria
 Some came from the chemical
separation of water molecules into
oxygen and hydrogen.
 Oxygen drove some life
forms to extinction
 Others evolved ways of
using oxygen for respiration
How did life begin?
Miller and Urey’s
Experiment
 Passed sparks
through a mixture of
hydrogen methane
ammonia and water
 This produced
amino acids – the
building blocks of life
Miller’s
experiment
suggests that
lightning could
have produced
amino acids