Species Variation Over Time

QUESTION????? HOW HAVE TELEPHONES CHANGED OVER TIME?

What is Evolution? Evolution in biology, refers to the process through which species change over time. The change results from a change in genetic material of an organism and is passed on from one generation to the next.

Jean Baptiste de Lamarck Lamarck was the 1 st scientist to propose a model of how life evolves. Through the use of fossils, he became convinced that an organism can acquire a new trait during its lifetime and pass it on to its offspring. Ex: Giraffes long necks

Lamarck’s Giraffes

Charles Darwin Lamarck was unable to come up with evidence to support his idea. Charles Darwin spent 5 years traveling across the coast of South America, studying rock formations and fossils.

Darwin’s Travels

Charles Darwin Darwin visited the Galapagos Islands, a chain of volcanic islands 600 miles off the coast of South America. He found that plants and animals on the islands differed from those on the mainland as well as those on other islands.

Darwin’s Tortoises He noticed tortoises with short necks lived in damp areas with abundant plants while those with long necks lived in dryer areas with cacti.

Darwin’s Finches

Darwin is most noted for his observations of a bird called a finch. Darwin noticed that among the different islands, there was a variety of beak shapes and sizes.

Darwin’s Finches Some finches had heavy short beaks for pecking trees or seeds, while others had small think beaks for capturing insects.

Natural Selection Darwin proposed a process called “natural selection”. Natural selection states that members of a species that are best suited to their environment survive and reproduce at a higher rate than other members of the species.

Species Variation There are four things that mainly contribute to variation among species. 1. Genetics 2. Geographic isolation 3. Interspecies Interactions 4. Climate

Species Variation The more variation you have in a species, the better the survival rate. ???????????????????????????????????????? WHY DO YOU THINK MORE VARIATION PROMOTES BETTER SURVIVAL RATE IN A PARTICULAR SPECIES?

SPECIES VARIATION Variation comes from the gene pool. In order for new traits to develop, you must have time! It takes 100’s of years for new traits to evolve, they don’t occur automatically.

New traits develop in a species because a different set of characteristics becomes more of an advantage in a particular climate setting.

Sometimes genetic material changes and this causes a new variation in a species. A change in genetic material is called a “mutation” Genetic variations are passed on to future generations.

Mutations can be: 1.Harmful: Ex- a color change may prevent an animal from being camouflaged. 2.Neutral: Eye color, fur length, ear size (these don’t affect survival) 3.Helpful: being small or large, faster runners, color that blends in with surrounds, claws for burroughing

Sometimes a mutation occurs that makes an individual better able to survive than other members of the group. This is called an adaptation. EXAMPLE: a slight change in the shape of a tail fin may increase a fish’s chance of survival by helping it swim faster.

Geographic Isolation The term “geographic isolation” means separated by land forms or water.

How Can Species Become Isolated? 1.Natural disasters: flooding, volcanic eruptions, fire 2.Human influence: building strip malls might prevent animals from migrating 3.Continental drift 4.island 5.Movement from one area to another

How can species become isolated? 4.Movement from one area to another 5.Island 6.Under water 7.Mountains create a barrier

Species isolation The changes that occur in an isolated population may be referred to as “separation”. If species become isolated from other group members, new traits may evolve that help the species survive in its particular location.

Species interaction occurs within different species.

1.Predator – Prey (hawk and mouse_ 2.Parasitism: One species helped, the other is harmed (tapeworm and human) 3.Mutualism: Both Benefit (termite and protozan) 4.Commensalism: One helped the other harmed (barnacle on whale)

Changes don’t occur because they are wanted or needed, but because they become more advantageous for survival.

Climate change leads to a loss of species Our planet is warming faster than at any time in the past 10,000 years. With these changes, species have to adapt to new climate patterns (variations in rainfall; longer, warmer summers etc). Global warming resulting from human emissions of greenhouse gases. The consequences include habitat loss; shifts in climatic conditions and in habitats that surpass migrational capabilities; altered competitive relationships.

Changes already underway Evidence suggests that the warming of the past century already has resulted in marked ecological changes, including changes in growing seasons, species ranges, and patterns of seasonal breeding. Global warming has the potential to cause extinctions in a majority of the world's especially valuable ecosystems.

Growing need for adaptations The fate of many species in a rapidly warming world will likely depend on their ability to migrate away from increasingly less favorable climatic conditions to new areas that meet their physical, biological, and climatic needs. Depending on a species responses to the warming, especially their ability to migrate to new sites, habitat change in many ecoregions has the potential to result in catastrophic species loss. \

Global warming is likely to have a winnowing effect on ecosystems, filtering out species that are not highly mobile and favouring a less diverse, more "weedy" vegetation and ecosystems that are dominated by pioneer species, invasive species.

Scientists have estimated that most species on this planet (including plants) will have to "move" faster than 1,000 metres per year if they are to keep within the climate zone which they need for survival. Many species will not be able to redistribute themselves fast enough to keep up with the coming changes. These species, as far as we know given present knowledge, may well become extinct.