EVOLUTION AND NATURAL SELECTION Why are the plants and animals of today different from the past? Why are there so many different types of plants and animals?

Evolution Means “change over time” This process refers to why the plants and animals of today are different than the ones from the past. The difference came from in a change in the genetic material (DNA) of an organism and is passed from one generation to the next.

Early Ideas of Evolution Jean Baptiste de Lamark 1st to propose that the fossil records showed that species had changed over time. His idea of evolution was based on the idea that an individual could acquire new traits during their lifetime and pass those traits to their offspring.

Later Ideas of Evolution Charles Darwin British naturalist who traveled the world aboard the H.M.S. Beagle studying rocks, fossils, plants, and animals. Species evolve through the process of natural selection. Darwin’s observations and conclusions are now part of the modern Theory of Evolution Published his ideas in the book “On the Origin of Species”

Darwin’s Observations His most famous observations came from the Galapagos Islands. Each species seemed to be adapted to its specific environment.

Darwin’s Observations Tortoises with short necks lived in damp areas with food on the ground Tortoises with longer necks lived in dry areas with cacti

Darwin’s Observations The finches of the islands had a variety of beak shapes and sizes Each beak was specific to the type of food the finch ate, which depended on the food available to them on their section of the islands.

Natural Selection Members of a species that are best suited for their environment survive and reproduce at a higher rate than other members of the species. Often called “Survival of the Fittest”

Lamarck vs. Darwin

Let’s watch Brain Pop!!! Darwin as an older man.

Four parts of Natural Selection Overproduction When a plant or animal reproduces it usually makes more offspring than an environment can support. Selection

Four parts of Natural Selection Variation Within a species there are natural differences, or variations, in traits. These variations are caused my mutations in the genetic material (DNA) These variations are inherited by offspring from their parent(s).

Four parts of Natural Selection Adaptation Sometimes a mutation is beneficial (helps the organism survive better)

Four parts of Natural Selection Individuals with beneficial adaptations are more likely to survive long enough to reproduce and pass on those traits. Over time, the species changes as the trait becomes more common with each passing generation.

Speciation The evolution of a new species from an existing species. Occurs when the organism’s environment changes. Can be caused by Isolation Members of a species get separated and cannot reproduce with one another Each population develops unique genetic differences.

Quick Check The process that refers to a species changing over time is called ____. overpopulation natural Selection evolution speciation

Quick Check 2. Which describes Lamarck’s explanation for changes in the fossil record? Species best suited to their environments survive better than other. Variation within a species can be passed on to offspring. Acquired traits are passed on from one generation to the next. Individual giraffes adapted to their environment.

Quick Check 3. The process of ___ states that a species that is best suited to their environment will survive longer and reproduce at a higher rate than other members. overpopulation natural Selection evolution speciation

Quick Check 4. Variations or natural differences within a species is caused by ____ in the genetic material. mutations selections evolutions speciation

Quick Check 5. ____ occurs when a species is separated and each groups develops unique genetic differences. Overpopulation Natural Selection Evolution speciation