Evolution

A change over a period of time Evolution A change over a period of time

Environment and Evolution Changes need to be long-term : species do not evolve because of a change in seasons

Changes can include: Climate change Change in temperature Change in water availability Change in food availability Introduction of a new species (new food, new predator) Species may be moved to a new location (accidently taken to an island for example

Environmental change DOES NOT CAUSE evolution to occur Environmental change DOES NOT CAUSE evolution to occur. A temperature or a climate change does not itself force a species to change its Genetics If this were the case, the all species would be able to adapt to the new environment and extinction would be a very rare event

Environmental Change A change in the environment can affect an organisms ability to survive Environmental changes can lead to selection

What is extinction? Extinctions occur when the last individual of a species dies out. Functional Extinctions occur when individuals remain but the odds of sustainable reproduction are low i.e. the species is effectively extinct even though individuals remain.

Modern Causes of Extinctions Major current causes of extinctions include: Habitat Loss: fragmentation, degradation, and outright destruction of ecosystems that support native ecosystems (leading cause). Invasive Species: the introduction or overpopulation of species that over-consume natural resources and are uncontrolled by predators (second leading cause). Over-harvesting: the removal of species at rates that exceed reproduction Pollution: introduction of harmful agents that reduce the effectiveness of a species’ adaptations

Bill Nye (worksheet) http://www.dailymotion.com/video/x3jyuu0

Evidence of evolution Video (8 minutes) https://www.youtube.com/watch?v=lIEoO5KdPvg

The passenger pigeon The last passenger pigeon in Wisconsin was shot at Babcock, in September, 1899. This is reportedly the last passenger pigeon shot in the wild. The last Passenger Pigeon, named Martha, died alone at the Cincinnati Zoo at about 1:00 pm on September 1, 1914. Within a few decades, the once most-numerous bird on Earth would be forever gone. Even when Martha was still alive, the species was already functionally extinct – it would never return to a sustainable population.

Last of these birds died in 1987 Dusky Seaside Sparrow Last of these birds died in 1987 Sparrows lost their homes as marshes were destroyed

When do extinctions occur? Extinctions occur when the environment of a species changes faster than the species can adapt. In other words, a species’ adaptations are no longer sufficient in allowing that species to acquire and compete for resources. Extinctions can be local, widespread, or global. For example, the timber wolf was until recently extinct in Wisconsin but not in Minnesota Wild elk and woodland caribou are now extinct in Wisconsin but may be found on game farms.

Mass Extinctions Cretaceous-Tertiary Extinction (65 mya). End Triassic Extinction (200). Permian Triassic Extinction (250). Late Devonian Extinction (364). Ordovician-Silurian Extinction (440). Holocene Extinction (0 mya) (#= millions of years ago) Source: http://www.uwec.edu/jolhm/EH4/Extinction/Extinction.ppt

DINOSAURS WHERE DID THEY GO?

Dinosaurs What do we know about them? Dinosaurs lived on earth more than 215 million years ago They lived in most parts of the world They ruled the earth for nearly 150 million years Dinosaurs have been extinct for 65 million years Extinct – something that once alive but no longer exist anywhere on the earth

How Do We Know About Dinosaurs? Paleontologist – scientist who studies fossils Fossil – what is left of a plant or animal that lived long ago Dinosaur – animal that lived millions of years ago Dinosaurs were not lizards or reptiles but many did lay eggs. Some had skin like crocodiles while others skin was much smoother.

What Have Scientist Learned From Dinosaur Fossils? There were different types of dinosaurs: Some were small Like a chicken Some were tall 3 story building Some were plant-eaters Flat teeth Some were meat-eaters Sharp teeth

Scientist have different theories on why dinosaurs are extinct. A theory is an idea based on scientific evidence.

The herbivores, or plant eating dinosaurs starved without any food. Some scientists believe dinosaur extinction happened because an asteroid hit the earth, causing most plants to die. The herbivores, or plant eating dinosaurs starved without any food.

Another theory of extinction is that asteroids caused massive fires that killed most plant life and the dinosaurs.

Other scientists believe something drastic happened to make earth’s global temperatures very cold. With temperatures so cold, dinosaurs either froze to death, or all plant life died. Herbivores then had nothing to eat.

Another theory of extinction is that many volcanic eruptions occurred.

Some scientists believe all the dinosaurs died from disease.

How is this relevant now? Current Stats 90% of all large fish have disappeared in the last 50 years due to over-fishing. The Audubon Society reports that 30% of North American songbird species are in significant decline. One in eight plant species are in danger of extinction within the next 30 years (ICUN Red List) The current rate of extinction is 1500 times greater than the normal, sustainable extinction rate. “Half of bird and mammal species will be gone in 200 to 300 years” One species is going extinct every 20 minutes.

Endangered Threatened Definitions Endangered A species of plant or animal that is in immediate danger of becoming extinct and needs protection to survive. Threatened A species is likely to become endangered if it is not protected

What about Endangered Species? To Be Continued!

Resurrection extinct animals https://www.youtube.com/watch?v=68QhIQLeVUA