Transcript Ontogeny Recapitulates Phylogeny

Ontogeny Recapitulates
Phylogeny
How We Classify and Why!
ONTOGENY

DEVELOMENT
VARIATION, CHANGE, SELECTION,
SURVIVAL AND REPRODUCTION


WHAT IS A SPECIES?
A SPECIES IS A GROUP OF ORGANISMS
THAT BREED TOGETHER UNDER
NATURAL CONDITIONS AND HAVE
VIABLE OFFSPRING. THEY ARE
ISOLATED IN SOME WAY FROM
OTHER SUCH GROUPS.
DIFFERENT SPECIES

THERE IS NO SUCH CATEGORY
CALLED SPECIE. THE WORD SPECIES
IS USED IN A SINGULAR FASHION, AS
WELL AS FOR MORE THAN ONE. –
ONE SPECIES, TWO SPECIES, ETC.

ALL MEMBERS OF A SPECIES FORM A
POPULATION. A POPULATION IS A
GROUP OF ORGANISMS
REPRESENTED BY A SINGLE SPECIES.
POPULATION

POPULATIONS OF DIFFERENT
ORGANISMS MAKE UP A COMMUNITY.
COMMUNITY





ORGANISMS IN NATURE HAVE A TOUGH
LIFE
THEY MUST FACE ENVIRONMENTAL
CHANGES
THEY MUST CONTEND WITH PREDATION
AND PARASITISM
THEY MUST UNDERGO CHANGE THROUGH MUTATIONS
THROUGH ALL OF THIS, THEY MUST
STRIVE TO SURVIVE AND REPRODUCE

YES, IT’S TRUE. THERE IS NO ONE
EXACTLY LIKE YOU. YOU ARE AN
INDIVIDUAL THAT IS UNLIKE ANY
OTHER INDIVIDUAL.

Dr. H.R.Hermann




SOME TYPES OF VARIATION
ANATOMICAL
PHYSIOLOGICAL
BEHAVIORAL
CHANGES ARE CONSTANTLY OCCURING IN THE PHYSICAL
WORLD













GLOBAL WARMING – OVER LONG PERIODS OF TIME, CHANGES SEA LEVEL
AS WELL AS CLIMATES
GLOBAL COOLING
CONTINENTAL DRIFT – SEPARATES SOME GROUPS OF ORGANISMS AND
BRINGS OTHERS TOGETHER
CHANGING WIND CURRENTS
CHANGING OCEAN CURRENTS
CHANGING CLIMATE – ALTERS COMMUNITIES
POLAR SHIFTS
VOLCANIC ACTIVITY – DESTROYS ENVIRONMENTS
EARTHQUAKES – QUICKLY CHANGES AN ENVIRONMENT
MOUNTAIN FORMATION – PROGRESSIVE, LONG-TERM CHANGES THAT
OFTEN RESULT FROM CONTINENTAL DRIFT
EROSION – NEW CHEMICALS ARE ADDED TO THE ENVIRONMENT
RAINFALL – PROVIDES WATER, FACILITATES LIFE, FACILITATES
DECOMPOSITION, CHANGES ENVIRONMENTS – HYDROGEN BONDING
BETWEEN WATER MOLECULES OFFERS CERTAIN FEATURES THAT ARE
USED BY ORGANISMS, E.G., SPIDERS, INSECTS, LIZARDS, ETC.
RIVERS, LAKES, PONDS, LAKES FORM AND DISAPPEAR
ENVIRONMENTAL CHANGES

THESE CHANGES IN OUR EARTH PUT
PRESSURES ON POPULATIONS OF
ORGANISMS, SUBJECTING THEM TO
STRESSES THAT WILL MAKE
POPULATIONS CHANGE.

ALONG WITH THESE CONSTANT
CHANGES, VARIATION WITHIN ALL
POPULATIONS TENDS TO CHANGE THE
POPULATIONS OVER TIME. FEATURES
POSSESSED BY CERTAIN INDIVIDUALS
WITHIN A POPULATION MAY HELP THEM
SURVIVE BETTER THAN OTHERS. THOSE
INDIVIDUALS THAT ARE BEST SUITED TO
THE CURRENT CONDITIONS ARE THE
ONES TO SURVIVE AND REPRODUCE.

THIS IS WHAT NATURAL SELECTION
IS ALL ABOUT – THE POSSESSION OF
CERTAIN TRAITS THAT HELP AN
INDIVIDUAL SURVIVE AND PASS ON
ITS GENES TO SUCCEEDING
GENERATIONS.




SUMMARY OF SOME IMPORTANT
FEATURES IN POPULATIONS
VARIATION – ALL POPULATIONS SHOW
VARIATION
CHANGE – CHANGES ARE CONSTANTLY
OCCURING. NOTHING IS STATIC.
SELECTION OF INDIVIDUALS THAT BEST
SUIT THE ENVIRONMENT – NATURAL
SELECTION – BIOLOGISTS SPEAK OF
MAXIMIZATION.






HISTORY OF PHILOSOPHY
BEFORE THE 1700S, BOTH SCIENCE AND PHILOSOPHY
WERE INFLUENCED BY RELIGIOUS BELIEFS.
DURING THE 1500S, PHILOSOPHERS BEGAN TO THINK ON
THEIR OWN AND BEGAN TO LOOK CRITICALLY AT THE
NATURAL WORLD.
IT WASN’T UNTIL THE 1800S THAT SCIENCE BEGAN TO TAKE
OFF AND MAKE IMPORTANT BREAK-THROUGH
DISCOVERIES.
BY THE MID 1800S EARLY 1900S, BIOLOGY HAD BECOME
INTERESTING TO NATURALISTS.
SINCE THAT TIME, BIOLOGISTS AND OTHER SCIENTISTS
HAVE BECOME SPECIALISTS

Dr. H. R. Hermann
Evolution, Genetics Embryo's and
our Common Ancestor's

http://www.youtube.com/watch?v=h3Lkac890c
0