Ms. Muneer

Many scientists before Darwin proposed theories of evolution However, they could not offer explanation for how living things change

Published Principles of Geology in 1830 Earth has been changed by the same process in the past as can be observed occurring in the present Geological change is slow and gradual rather than sudden and catastrophic Natural laws and processes are constant and eternal, and they operated with the same kind of intensity in the past as they do in the present

Proposed that species could change over time and that these changes could lead to new organisms Pigs extra toes… picture

proposed that life changed over time and that all life might have evolved from a single original source

First scientist to offer a possible mechanism for the evolution of species Unlike the previous scientists, Lamarck did not believed that single species could give rise to additional species Argued that each species gradually became more complex and that new very simple species were continually being created by spontaneous generation Spontaneous generation – idea that living organisms arise from non-living matter Proposed two distinct principles

Use and disuse “use it or lose it” Used structures became larger and stronger Structures not used became weaker and smaller

Exercise will cause it to increase Reduced muscle mass in astronauts

Inheritance of acquired characteristics Acquired traits – changes in an individual resulting from interactions with the environment Individuals could pass down their acquired characteristics to their offspring

Today we know that Lamarck’s was flawed Ex – your vision does not improve the more you use your eyes It is possible to stretch your neck slightly, but it will not alter you DNA and your children will not be born with longer necks

All species evolve over time A species evolves in response to its environment and becomes better adapted to that environment Changes are passed on from generation to generation

Charles Darwin

Returned to England in 1836 after a 5 year trip In 1837 – started to write his first notebook Some of the most compelling evidence for evolution comes from biogoegraphy – observed geographic patterns of distribution of species Notes loss of fear

Realized that patterns he had observed regarding the distribution of species, both living and extinct, were evidence that species might have evolved Hypothesized that remote oceanic islands became populated by species that arrived by water or air After the species became established, many evolved into new species over time

Observations from the Galapagos Islands Darwin’s hypotheses regarding remote islands Many species of plants, birds insects, and, in some cases reptiles Only these kinds of organisms are able to reach remote islands by crossing large expanses of open ocean No native amphibians and very few land mammals Amphibians and most mammals are unable to cross open ocean and will not be found in remote islands Many unique species found nowhere else on Earth Over time, ancestral species have evolved into new geographically isolated species Unique species most closely resemble species on the nearest continental land mass Unique species are descendents of ancestral species from the nearest continental land masses and will exhibit some similarities

Please DO NOT TOUCH When observing: Think about similarities in their bone structures What similarities do you see in the bone structures? How may these species be related? Do the similar bone structures have the same functions? Do the similar bone structures have the different functions?

A structure with a common evolutionary origin that may serve different functions in modern species Adapted to serve different functions in different species

He had no understanding of chromosomes and genes He knew that many traits were inherited from generation to generation Was also aware that artificial breeding of animals and plants could, over many generations, produce dramatic results

Features that perform similar functions Not similar in origin or anatomical structure

Features that no longer serve he function they do in similar species Rudimentary and/or non-functioning Homologous to a fully function structure in closely related species

Evolution Debate