- Slides: 30
CHARLES DARWIN Catastrophism Uniformitarianism
INTRODUCTION � Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809– 1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. � Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. � It is a key mechanism of evolution.
CHARLES DARWIN � Charles Robert Darwin [12 February 1809 – 19 April 1882] was an English naturalist, geologist and biologist , best known for his contributions to the science of evolution. � His proposition that all species of life have descended over time from common ancestors is now widely accepted, and considered a foundational concept in science. � In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection,
VARIATIONS � In every species there is variation. This variability occurs even between related individuals. � Siblings vary in color, height, weight and other characteristics. Other characteristics rarely vary, such as number of limbs or eyes. The observer must be careful when making generalizations about a population. � Some populations show more variation than others, particularly in geographically isolated areas such as Australia, the Galapagos, Madagascar and so forth. � Organisms in these areas may be related to those in other parts of the world.
INHERITED TRAITS � Each species has traits determined by inheritance. � Inherited traits passed from parents to offspring determine the characteristics of the offspring. � Inherited traits that improve the odds of survival are more likely to be passed on to subsequent generations. � For example, if an organism inherits the genes for a larger skeletal mass but lack of nutrition prevents the individual from growing to that size, and if the individual survives and reproduces, the genes for the larger skeleton will be passed on.
COMPETITION � Offspring Compete : - Most species produce more offspring each year than the environment can support. � This high birth rate results in competition among the members of the species for the limited natural resources available. � The struggle for resources determines the mortality rate within a species. � Only the surviving individuals breed and pass on their genes to the next generation.
SURVIVAL OF THE FITTEST � Some individuals survive the struggle for resources. These individuals reproduce, adding their genes to the succeeding generations. � The traits that helped these organisms to survive will be passed on to their offspring. This process is known as “natural selection. ” � Conditions in the environment result in the survival of individuals with specific traits which are passed through heredity to the next generation. Today we refer to this process as “survival of the fittest. ”
Catastrophism Speculating that each boundary between strata represents a catastrophe
Catastrophism Its about change over time
Descent with modification by natural selection -adaptations of organisms and the unity and diversity of life
Natural Selection Individuals with favourable inherited traits are more likely to survive and reproduce
The Origin of Species
COPERNICAN REVOLUTION 1. Why does the sun exhibit daily motion across the sky each day? 2. Why do the Sun and planets appear to move eastward along the Zodiac? 3. How can planetary brightness variations be explained? 4. Why are Mercury and Venus never seen opposite of the Sun in the sky? 5. Why do some planets have retrograde motion that causes them to appear to go backwards?
Copernican Model Ø Heliocentric Universe Ø De Revolutionibus Orbiun Celestium (On the Revolutions of the Heavenly Spheres) Ø Idea was opposed by the Catholic Church
Copernican Model Copernicus has no clue what stars actually are or how far they are away
�Earth’s rotation caused daily motion from east to west. �Mercury and Venus were inferior planets, which explained why they are always seen near the Sun. �Sun’s annual motion along the ecliptic (Zodiac) was caused by Earth’s orbital motion (this one was difficult to accept. ) �Retrograde motion was a natural phenomenon of one planet passing another planet as they orbited the Sun.
FREUDIAN REVOLUTION � Freud: We have a tri-partite (three-part) self �Id – That most infantile and demanding part of the self that is insatiable; ruled by the “Pleasure Principle” that aims to find pleasure and avoid pain �Ego – The part of the self that battles against the Id and Superego with reason, logic, and rationale; ruled by the “Reality Principle”: You can’t always get what you want; helps the Id make it until urges/desires can be satisfied �Superego – Unreasonably abuses you for shirking your responsibilities and not living up to your potential; contains rules concerning what constitutes good or appropriate behavior as well as standards concerning what constitutes bad, immoral, or embarrassing behavior
Freud’s Theories Note that the Id exists exclusively in the unconscious. The Ego and Superego battle to keep the Id in check. Likewise, the Ego battles with reason against the unreasonable demands of both the Id and the Superego.
Freud’s Theories Top of the iceberg: Conscious mind (smallest part – say, 10%). We can access this, we are aware of this part of “us. ” We understand it logically.
Freud’s Theories Middle of iceberg: Preconscious (medium size, about 10 -15%). Ordinary memory. You don’t keep a lot of information in your conscious mind all the time – why? If you need to know something (where you parked your car, your sister’s birthday, your 7 th grade Stardust Dance, etc. ) you can bring it “up”) to your Conscious mind.
Freud’s Theories Bottom of iceberg: Unconscious (huge – dwarfs the other two, 75 -80% of our mind). “Underwater” The unconscious: Plays a very large role in how we function as human beings. Most of the work among the Id, Ego, and Superego happens here.