evolution evolution – change in a kind of organism over time

EVOLUTIONEVOLUTION

Evolution Evolution – – ChangeChange in in

a kind of organisma kind of organism over over timetime

EVIDENCE OF EVOLUTIONEVIDENCE OF EVOLUTION

EVIDENCE FROM FOSSILSEVIDENCE FROM FOSSILS

Fossils are traces of once living Fossils are traces of once living organisms found most commonly in organisms found most commonly in sedimentary rock.sedimentary rock.

Sometimes the fossil can be from hard Sometimes the fossil can be from hard parts of an organism including shells, parts of an organism including shells, bones, teeth and woody stems.bones, teeth and woody stems.

Fossils can be trapped in hardened Fossils can be trapped in hardened resin (like insects) or frozen in Arctic resin (like insects) or frozen in Arctic ice (like a woolly mammoth) with skin, ice (like a woolly mammoth) with skin, bones and muscle perfectly preserved.bones and muscle perfectly preserved.

EVIDENCE FROM FOSSILS EVIDENCE FROM FOSSILS (continued)(continued)

Fossils are not always body parts: Fossils are not always body parts: Example – Imprint – a film of carbon Example – Imprint – a film of carbon

remains after all other parts have remains after all other parts have decayed.decayed.

Mold – when an impression of the Mold – when an impression of the shape or track of an organism has shape or track of an organism has survived.survived.

Cast – forms when sediments fill in Cast – forms when sediments fill in the cavity left by a mold fossil.the cavity left by a mold fossil.

EVIDENCE FROM LIVING EVIDENCE FROM LIVING ORGANISMSORGANISMS

Common ancestry – deer and elk – both are Common ancestry – deer and elk – both are possibly from a now extinct Irish Elkpossibly from a now extinct Irish Elk

Homologous structures – parts that have Homologous structures – parts that have similar structures but different functionssimilar structures but different functions

Vestigial Organs – seemingly functionless Vestigial Organs – seemingly functionless parts.parts.

Examples: – tailbone and appendix in Examples: – tailbone and appendix in humanshumans

some species of snakes have tiny pelvic some species of snakes have tiny pelvic bones (Anaconda in S America)bones (Anaconda in S America)

small limb bones (boa and python)small limb bones (boa and python) some cave dwelling salamanders have eyes some cave dwelling salamanders have eyes

even though members of the same species even though members of the same species are blind.are blind.

EVIDENCE OF EVOLUTION FROM EVIDENCE OF EVOLUTION FROM LIVING ORGANISMS (continued)LIVING ORGANISMS (continued)

Embryological Development – Embryological Development – Embryos of certain species Embryos of certain species develop almost identically.develop almost identically.

DNA analysisDNA analysis Biochemistry – example – the Biochemistry – example – the

metabolism of different metabolism of different organisms is based on the same organisms is based on the same complex biochemical complex biochemical compounds.compounds.


GeographyGeography *Geographic isolation of a species occurs when a *Geographic isolation of a species occurs when a

physical barrier, such as a mountain range, stops physical barrier, such as a mountain range, stops members of two populations of a species from members of two populations of a species from coming into contact with each other. coming into contact with each other.

*Interbreeding between the two populations is not *Interbreeding between the two populations is not possible. possible.

*Different environmental factors may favor one *Different environmental factors may favor one adaptation over the other in the two groups. In time adaptation over the other in the two groups. In time the populations may become different enough that the populations may become different enough that they can no longer interbreed. (Reproductive they can no longer interbreed. (Reproductive isolation has taken place.)isolation has taken place.)

Antibiotic and Pesticide resistance – explain Antibiotic and Pesticide resistance – explain


Viral evolution – explainViral evolution – explain Over the years, breeders have Over the years, breeders have

used artifical selection (selective used artifical selection (selective breeding) to produce plants and breeding) to produce plants and animals that are much more animals that are much more suited to human needs. These suited to human needs. These animals are often dramatically animals are often dramatically different in appearance from different in appearance from their original parent stock.their original parent stock.

MASS EXTINCTIONMASS EXTINCTION

Mass Extinction is the sudden Mass Extinction is the sudden disappearance of many species. disappearance of many species.

It is often followed by the rapid It is often followed by the rapid evolution of many new species known evolution of many new species known as adaptive radiation. as adaptive radiation.

They fill in the “niche” left by the They fill in the “niche” left by the mass extinctionmass extinction

Example – large mammals filled in the Example – large mammals filled in the “niche” left by the extinction of “niche” left by the extinction of dinosaursdinosaurs

MASS EXTINCTION TIME LINE MASS EXTINCTION TIME LINE “THE BIG 5”“THE BIG 5”

Five main extinction events have been Five main extinction events have been recognized, these are known as the recognized, these are known as the BIG 5.BIG 5.

Number 1Number 1 The late Ordovician event 438 million years ago, The late Ordovician event 438 million years ago,

when 100 families went extinct when 100 families went extinct Caused by a drop in sea levels as glaciers formed, Caused by a drop in sea levels as glaciers formed,

then by rising sea levels as glaciers melted. then by rising sea levels as glaciers melted. (The toll: 25 percent of marine families and 60 (The toll: 25 percent of marine families and 60

percent of marine genera.)percent of marine genera.)

THE BIG 5 (CONTINUED)THE BIG 5 (CONTINUED) NUMBER 2NUMBER 2 Late Devonian 360 million years ago, when 30% Late Devonian 360 million years ago, when 30%

of families went extinct of families went extinct Cause unknownCause unknown (Killed 22 percent of marine families and 57 (Killed 22 percent of marine families and 57

percent of marine genera.) percent of marine genera.)

THE BIG 5 (CONTINUED)THE BIG 5 (CONTINUED) NUMBER 3NUMBER 3 End Permian-Triassic extinction - 245 million End Permian-Triassic extinction - 245 million

years ago, the biggest extinction of all time when years ago, the biggest extinction of all time when over 50% of all families were lost.over 50% of all families were lost.

There are many ideas as to what caused the There are many ideas as to what caused the extinctionextinction

The Permian-Triassic catastrophe was Earths The Permian-Triassic catastrophe was Earths worst mass extinction, killing 95 percent of all worst mass extinction, killing 95 percent of all species.species.

(53 percent of marine families, 84 percent of (53 percent of marine families, 84 percent of marine genera and an estimated 70 percent of marine genera and an estimated 70 percent of land species such as plants, insects and land species such as plants, insects and vertebrate animals. )vertebrate animals. )

THE BIG 5 (CONTINUED)THE BIG 5 (CONTINUED) NUMBER 4NUMBER 4 Late Triassic 199 million to 214 million years ago Late Triassic 199 million to 214 million years ago

35% of families died out35% of families died out most likely caused by massive floods of lava most likely caused by massive floods of lava

erupting from the central Atlantic magmatic erupting from the central Atlantic magmatic province -- an event that triggered the opening of province -- an event that triggered the opening of the Atlantic Ocean. the Atlantic Ocean.

The volcanism may have led to deadly global The volcanism may have led to deadly global warming. Rocks from the eruptions now are found warming. Rocks from the eruptions now are found in the eastern United States, eastern Brazil, North in the eastern United States, eastern Brazil, North Africa and Spain. Africa and Spain.

(The death toll: 22 percent of marine families, 52 (The death toll: 22 percent of marine families, 52 percent of marine genera. Vertebrate deaths are percent of marine genera. Vertebrate deaths are unclear.)unclear.)

THE BIG 5 (CONTINUED)THE BIG 5 (CONTINUED) NUMBER 5NUMBER 5 The Cretaceous Tertiary (K-T) 65 Million years The Cretaceous Tertiary (K-T) 65 Million years

ago, which ended the reign of the dinosaurs ago, which ended the reign of the dinosaurs probably caused or aggravated by impact of several-mile-probably caused or aggravated by impact of several-mile-

wide asteroid that created the Chicxulub crater now hidden wide asteroid that created the Chicxulub crater now hidden on the Yucatan Peninsula and beneath the Gulf of Mexico. on the Yucatan Peninsula and beneath the Gulf of Mexico.

Some argue for other causes, including gradual climate Some argue for other causes, including gradual climate change or flood-like volcanic eruptions of basalt lava from change or flood-like volcanic eruptions of basalt lava from India’s Deccan Traps. India’s Deccan Traps.

Others believe that diseases brought from dinosaurs as Others believe that diseases brought from dinosaurs as they migrated across the land bridges that were present they migrated across the land bridges that were present contributed to the destruction. contributed to the destruction.

(The extinction killed 16 percent of marine families, 47 (The extinction killed 16 percent of marine families, 47 percent of marine genera (the classification above species) percent of marine genera (the classification above species) and 18 percent of land vertebrate families, including the and 18 percent of land vertebrate families, including the dinosaurs.) dinosaurs.)

CLADOGRAMSCLADOGRAMS

A A CLADOGRAMCLADOGRAM IS USED IN CLADISTIC IS USED IN CLADISTIC TAXONOMYTAXONOMY

SHOWS RELATIONSHIPS OF ORGANISMS SHOWS RELATIONSHIPS OF ORGANISMS BASED ON BASED ON SHARED CHARACTERISTICSSHARED CHARACTERISTICS

USED TO ESTABLISH EVOLUTIONARY USED TO ESTABLISH EVOLUTIONARY RELATIONSHIPS RELATIONSHIPS

TO INTERPRET A CLADOGRAM, BEGIN AT TO INTERPRET A CLADOGRAM, BEGIN AT THE BOTTOM AND MOVE UPTHE BOTTOM AND MOVE UP

CladogramCladogram Diagram showing how organisms Diagram showing how organisms

are related based on are related based on shared, shared, derived characteristicsderived characteristics such as such as feathers, hair, or scalesfeathers, hair, or scales

Primate Primate CladograCladogra

mm

Dating of FossilsDating of Fossils

Relative Dating – A method of Relative Dating – A method of determining the age of a fossil by determining the age of a fossil by comparing them to other fossils in comparing them to other fossils in different layers of rock.different layers of rock.

Radioactive Dating – a method of Radioactive Dating – a method of determining the age of an object by determining the age of an object by measuring the amount of a specific measuring the amount of a specific radioactive isotope it contains.radioactive isotope it contains.

BIOLOGICAL EVOLUTIONBIOLOGICAL EVOLUTION

Biological evolution is a change in Biological evolution is a change in the allele frequency of a species or a the allele frequency of a species or a population over time.population over time.