There is no 'Great Plan" out there toconform with the evolutionary theory,just organisms struggling to pass theirgenes on to the next generation. That'sit."

Evolution

History of Evolution

Important Players

James Hutton Published studies in 1785 Geologist Theory of Uniformity- the earth was

created by the same forces that are in existence today (plate tectonics)

Before Hutton, world was thought to be 6000 years old and formed by catastrophic events, not geological ones

His research supported that the Earth to be millions of years old

Thomas Malthus Worked with human population

studies Observed that plants and

animals reproduce at a greater rate than their ability for survival, creating competition within a species

Important to Wallace and Darwin’s theory

Jean-Baptiste Lamarck

1809- 1st to develop a scientific theory of evolution known as Theory of inheritance of acquired characteristics:

Organisms developed new organs or modified old ones to meet environmental challenges

Working toward perfection- more complex, more perfectSelective use or disuse would alter the size or shape of organs or structures passed to offspring

Examples Larmarck Observed Long Neck giraffes - short neck

giraffes that strained to reach higher branches would grow longer necks

Fiddler crabs large claw (male) -developed one larger front claw because it used to claw often to attract mates and ward off predators

Lamarck’s Theory Proven to be False

Change DNA by usage of the structures (BOGUS! Mendel was not yet born so little was known about genetics). Think of body building and passing that on to your offspring

No extinction of species, just changed into other organisms

Lower order organisms were spontaneously created to fill the void (nothing was due to chance).

Alfred Wallace 1850’s Naturalist Developed a theory similar to

Darwin’s His essay to Darwin motivated

Darwin to publish the book, On the Origin of Species.

Charles Darwin

1830’s Known as the “Father of Evolution” Naturalist on the HMS Beagle (shipping

vessel) collecting specimens of flora and fauna and created detailed written observations

Inspired by the biological diversity of the Galapagos Islands

Voyage of the Beagle 5 year voyage began in 1831 Only 5 weeks spent on the

Galapagos Islands Found endemic species Saw variations of organisms on the

different islands (thought that this could be modification due to environment)

Evolution Terms Evolution – descent with modification /

changes over time

Adaptation – inherited characteristic that may increase organisms chance of survival

Speciation – formation of new species

Species – group of similar organisms that can breed in nature and reproduce fertile offspring.

Evolution Terms

Homologous Structures – similar structures found in different organisms that serve different functions

Analogous Structures – structures that are different in form but have the same function.

Evidence of Evolution Biochemistry – DNA and amino acids Embryological Development Fossil Record Morphology – form and structure of

organisms without consideration of function

Vestigial Organs - structure that no longer serves a useful function in an organism (ex. Human appendix)

Fossils Age of fossils can be determined by:

1. analyzing its position in the sedimentary layers

2. Radioactive dating

Archaeopteryx – earliest bird (had reptilian and bird –like characteristics

Vestigial Organ

4 Mechanisms for Change Natural Selection Mutation Migration Genetic Drift

Why are brown beetles more prevalent in a

population?

Each of the 4 mechanisms will change the gene pool frequency

Natural Selection Process in which organisms with

favorable traits (traits well suited for their environment) are more likely to survive and reproduceSurvival of the Fittest or the “Sexiest”

Imagine that green beetles are easier for birds to spot (and hence, eat). Brown beetles are a little more likely to survive to produce offspring. They pass their genes for brown coloration on to their offspring. So in the next generation, brown beetles are more common than in the previous generation.

Mutation change in DNA sequence that

causes a variation in the offspring A mutation could cause parents with

genes for bright green coloration to have offspring with a gene for brown coloration. This would make the genes for brown beetles more frequent in the population.

Migration Some individuals from a population

of brown beetles might have joined a population of green beetles. That would make the genes for brown beetles more frequent in the green beetle population.

Genetic Drift “Pure chance” Imagine that in one generation, two

brown beetles happened to have four offspring survive to reproduce.

Several green beetles were killed when someone stepped on them and had no offspring.

Patterns of Evolution Founder Effect Speciation Punctuated equilibrium Adaptive/Divergent Radiation Convergent evolution Coevolution

Founder Effect Organisms become separated or

isolated and the gene frequency changes

Founding organisms arrived on different islands of the Galapagos and due to the different availability of food slowly changed the gene pool of the population.

Speciation Reproductive isolation causes new

species to form Types of Isolation:

Behavioral Geographic Temporal

Punctuated Equilibrium Pattern of evolution in which long

stable periods are interrupted by brief periods of more rapid change

Hardy-Weinburg Theory No movement in or out of the

population No mutations No natural selection forces

Evolution Terms Adaptive/Divergent

Radiation – process that causes a single species to evolve into new forms and eventually new species

Homologous Structures

Evolution Terms Convergent

Radiation process by which unrelated organisms come to resemble one another because of similar environment

Analogous structures Cactus and spurge are another example

of convergent evolution.

Coevolution Two species that evolve in

harmony with one another because of the close interaction they have with each other