Warm up • Modern technology could be used to clone animals (like you favorite dog). Cloned animals would resemble the original pets because: • How is the process of gene therapy used to treat cystic fibrosis? • Describe the procedure represented in the diagram below using these terms? • Restriction enzyme • Recombinant DNA • Plasmid • Vector
The Theory of Evolution How did all of life on Earth come from a few cells? Simpson natural selection
Theory of Evolution • Charles Darwin is credited with the development of the theory of evolution, but there were many people that contributed ideas upon which he built his own.
Theory of Evolution • Darwin also developed his ideas based on his travels as the ship naturalist on the H.M.S. Beagle. • Of particular interest to Darwin were the animals of the Galapagos Islands.
Theory of Evolution • In 1859, Darwin and Alfred Wallace jointly proposed that new species could develop by a process of natural selection. • The theory can be described as a process:
Hutton and Lyell • Hutton- Earth has to be much more than a few thousand years • GEOLOGIC FORCES- forces that shape the world ( rocks, mountains, valleys) • Lyell • Processes that shaped the Earth millions of years earlier continue in present • Fossils of marine animals above sea level • Influence?: If the Earth could change over time, might life change as well?
Thomas Malthus • Essay on the Principal of Population- Malthus predicts that the human population will grow faster than the space and food supplies needed to sustain it • What factor/factors determine which ones survive and reproduce, and which do not?
Lamarck's Theory • Living things have changed over time • 1809- hypothesis (1st to develop) • Tendency toward perfection- continually changing and acquiring features that help them live more successfully in their environments • Use and disuse- organisms could alter the size or shape of particular organs by using their bodies in new ways • Inheritance of acquire traits- pass on traits to offspring • Evaluation of hypothesis • Did not know how traits are inherited • Did not know that behavior has no effect on heritance
Natural Selection Natural Selection • Variation of traits within the population leads to different phenotypes. • Some variations are better suited to the current conditions of the environment.
Natural Selection • Overproduction in populations leads to competition for limited resources (food, for example).
Natural Selection • Natural selection favors the best suited phenotype at the time. • This does not necessarily mean that those struggling die, but will be in a poorer condition
Natural Selection • The survival (or better success) of the best adapted individuals leads to higher reproductive success. • The variations will be passed on to the offspring • Over time, if the environment does not change, those favorable variations will be seen more frequently in the population because nature has “selected” that trait.
Fill It In … Steps of Natural Selection: 1. 2. 3. 4.
Inherited Variation and Artificial Selection • Inherited variation- differences that are passed from parents to offspring • Larger fruits on plants; some cows give more milk • Artificial selection- selection by humans for breeding of useful traits from the natural variation among different organisms • Animal breeders used heritable variation to improve livestock and crops
Evolution Through Natural Selection • The struggle for existence • More offspring are produced that can survive to maturity • Individuals compete for food, living space, and other necessities • Some variations increase the change of survival and REPRODUCE
Natural Selection • Central to the theory of natural selection is the idea of adaptations. • An adaptation is any heritable trait that suits an organism to its natural function in the environment (its niche).
There are 3 basic types of adaptations: • Examples of structural adaptations are defensive structures, camouflage, and mimicry. • Typically, mimicry occurs when harmless species (mountain king snake) resembles a harmful species (coral snake) using coloration.
There are 3 basic types of adaptations: • Examples of behavioraladaptations are herding, schooling, and growling.
There are 3 basic types of adaptations: • Examples of physiological adaptations are enzymes, oxygen-binding of hemoglobin, and sight
Decent with Modification • Principle that each living species descended with changes, from other species over time • Look different from ancestors • Implies that all living organisms are related to one another • Common descent- principle that all species were derived from common ancestors • “Tree of life” links all living things
Fill It In … A body-builder’s large muscles would NOT be an adaptation because …
Check Yourself! • Who is credited with developing the theory of natural selection? • List the four steps in the process of natural selection. • What is an adaptation?
Check Yourself! • Who is credited with developing the theory of natural selection? CHARLES DARWIN • List the four steps in the process of natural selection. • What is an adaptation?
Check Yourself! • Who is credited with developing the theory of natural selection? CHARLES DARWIN • List the four steps in the process of natural selection. VARIATION, OVERPRODUCTION, BEST SUITED IS FAVORED, & SURVIVAL OF BEST ADAPTED • What is an adaptation?
Check Yourself! • Who is credited with developing the theory of natural selection? CHARLES DARWIN • List the four steps in the process of natural selection. VARIATION, OVERPRODUCTION, BEST SUITED IS FAVORED, & SURVIVAL OF BEST ADAPTED • What is an adaptation? ANY HERITABLE TRAIT SUITS AN ORGANISM TO ITS NATURAL FUNCTION IN THE ENVIRONMENT