Evolution Change Over Time Definition change of species

Evolution Change Over Time……. Definition: change of species over time

Evidence of Evolution Key Concept Darwin Argued That Living Things Have Been Evolving On Earth For Millions of Years. Evidence For This Process Could Be Found In: The Fossil Record The Geographical Distribution of Living Species Homologous Structures of Living Organisms Similarities In Early Development DNA Comparisons –similarities in nucleotide sequences

What is a fossil? The preserved or mineralized remains (bone, tooth, or shell) or burrow, or traces (footprints, imprint) of an organism that lived long ago. Ammonite fossil (shell) Dinosaur fossil - (bone)

Fossils are very old Trilobite fossils 445 million years ago Beetle fossil 50 million years old Stingray fossil 95 million year old Bird egg fossil 1 million years old

Fossil Record Earth is Billions of Years Old Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time Gradualism: hypothesis that evolution occurs at a slow, constant rate

How do fossils form? Most fossils are laid down in sedimentary rock (particles carried by streams and rivers that eventually settle to the bottom in layers) Many fossils are found in the Grand Canyon

The oldest particles, and therefore the oldest fossils will be at the bottom, with new layers being added on top. The deeper down you go, the simpler the life forms are. This leads some to believe that life began as simple prokaryotic cells and gradually became more complex because…

Fossil record of the modern horse Today 55 million years ago

Voyage of the Beagle Charles Darwin Born Feb. 12, 1809 Joined Crew of HMS Beagle, 1831 Naturalist 5 Year Voyage around world Avid Collector of Flora & Fauna Astounded By Variety of Life

HMS Beagle The purpose of the trip was to draw accurate maps of the region. Darwin was to collect specimens and document the plant and animal life.

The Galapagos Islands Small Group of Islands 1000 km West of South America Very Different Climates Animals On Islands Unique Tortoises Iguanas Finches

Darwin’s Observations Patterns of Diversity were shown Unique Adaptations in organisms Species Not Evenly Distributed Australia, Kangaroos, but No Rabbits S. America, Llamas

Adaptation Process by which a species becomes better suited to its environment Organisms well suited to their environment reproduce at a greater rate than those less suited to the same environment Ex: Camouflage

Darwin’s Theory of Evolution • The unequal ability of individuals to survive and reproduce leads to a gradual change in a population, with favorable characteristics accumulating over generations (natural selection) • New species evolve

Geographic Distribution of Living Species Different Animals On Different Continents But Similar Adaptations To Shared Environments

Darwin’s Theory of Natural Selection 1. 2. 3. 4. 5. There is variation within any species All organisms tend to over-reproduce There is a struggle for survival The fittest survive The environment determines who is the fittest

1. Variation exists within every population Ladybugs have different spots

Zebras all have different stripes

2. All species tend to produce more offspring than they can SUPPORT Turtle eggs Insect eggs Baby mice Frog eggs

3. There is a Struggle for Survival 1. To eat 2. To drink 3. Territory 4. To mate

4. The fittest will survive

4. The fittest will survive Healthy or sick horse?

5. Nature (the environment) will determine which organism is the fittest to Survive long neck giraffes survive over short neck giraffes

Evidence of Natural Selection in our lifetime The Peppered Moth in England Before the industrial revolution After the industrial revolution

Natural Selection Driving force for evolution During the struggle for resources, strongest survive & reproduce Idea that at least some of the differences between individuals, which impact their survival and fertility, are inheritable

Natural Selection Organisms with traits well suited to their environments survive and reproduce at a GREATER rate than less well-adapted organisms in the same environment Causes changes in the frequency of certain alleles in a population

When do new species form? Subspecies diverge Because of natural selection Members of the same species become adapted to a new environment Speciation: process by which new species form http: //www. youtube. com/watch? v=YCo. Ei. LOV 8 jc

Theory of Evolution Today Supporting Evidence

Homologous Structures

Homologous Body Structures Scientists Noticed Animals With Backbones (Vertebrates) Had Similar Bone Structure May Differ In Form or Function Same Structure Example: Limb Bones Develop In Similar Patterns Arms, Wings, Legs, Flippers

Homologous Body Structures That Have Different Mature Forms But Develop From The Same Embryonic Tissues Strong Evidence That All Four-Limbed Animals With Backbones Descended, With Modification, From A Common Ancestor Nucleotide sequences show many similarities Help Scientist Group Animals

Homologous Body Structures

Analogous Body Structures Body structures that have the same function Example: All of the structures below are used for flight

Evidence for Evolution - Comparative Embryology Similarities In Embryonic Development

Some animals appear to have structures that no longer serve a function – (called vestigial structures) Vestigial leg bones in a python Structures that are just there because of the evolution of other structures

Vestigial wings in a flightless bird Ex a penguin and an ostrich

Human appendix is vestigial The human appendix has no function in humans but is very important in horses and other animals

Human tailbone is a vestigial vertebrate tail Human tail bone consists of fused vertebrae that no longer function as a tail

Evolutionary Time Scales Macroevolution: Long time scale events that create and destroy species.

Evolutionary Time Scales Microevolution: Short time scale events (generationto-generation) that change the genotypes and phenotypes of populations