4 3 How Do Geological Processes and Climate

4 -3 How Do Geological Processes and Climate Change Affect Evolution? • Concept 4 -3 Tectonic plate movements, volcanic eruptions, earthquakes, and climate change have shifted wildlife habitats, wiped out large numbers of species, and created opportunities for the evolution of new species.

Geologic Processes Affect Natural Selection • The earth’s surface has changed dramatically over its long history due to the movement of _______ plates… tectonic • Series of gigantic solid plates broken apart by _______ rock flowing from the earth’s interior molten • For hundreds of millions of years, these plates have mantle drifted slowly on the planet’s _________

Movement of the Earth’s Continents over Millions of Years Fig. 4 -8, p. 89

Geologic Processes Affect Natural Selection • Tectonic plate drift has two important effects on evolution… • First…locations (________) of continents and latitudes oceans have shifted, exposing them to different climates ________ move • Second… species physically ______ with the continents and their populations must ______ adapt new environments…may eventually form new to ______ species through natural selection

Geologic Processes Affect Natural Selection • Plate movement may also alter populations through… shifts • Earthquakes …due to _____ which may cause fissures • Can _________ or isolate members of a separate population • Volcanic eruptions along the ________ of boundaries plates • can ______ or wipe out populations destroy

Climate Change and Catastrophes Affect Natural Selection • The earth’s changing climate has also affected populations • Sometimes it has cooled and covered much of the earth with ________ ice glacial • Other times it has warmed, melted the ice, and raised drastically ________ sea levels • Such cooling and heating periods have led to the advance and retreat of ice sheets at _____ higher northern latitudes over much of the ________ hemisphere

Changes in Ice Coverage in the Northern Hemisphere During the last 18, 000 Years Fig. 4 -9, p. 89

asteroid • Catastrophic events, such as _________ impact, have also affected populations and natural selection… • Species may have been wiped out locations • Or may have caused shifts in the _________ of ecosystems creating opportunities for the evolution ________ of new species

Science Focus: Earth Is Just Right for Life to Thrive • Temperature range: most life on earth requires a freezing temp. range between the ________ and boiling _______ points of water moderate • Orbit size: ________ temperature (Venus is too hot and Mars is too cold) • Liquid water: necessary for life (Venus has water _____ and Mars has _____) vapor ice fast • Rotation speed: _______ enough to prevent the sun from overheating earth’s surface gravitational • Size: enough ________ mass to keep our atmosphere from flying off into space

4 -4 How Do Speciation, Extinction, and Human Activities Affect Biodiversity? • Concept 4 -4 A As environmental conditions change, the balance between formation of new species and extinction of existing species determines the earth’s biodiversity. • Concept 4 -4 B Human activities can decrease biodiversity by causing the extinction of many species and by destroying or degrading habitats needed for the development of new species.

How Do New Species Evolve? Under certain situations, natural selection can lead to an entirely new species splits • Speciation: one species ______ into two or more species • For sexually reproducing organisms, a new species has formed when one population has evolved to the point no longer where it can _________ breed and produce fertile offspring with a previous population

How Do New Species Evolve? The most common way that speciation occurs is when a barrier migration prevents the ________ or distant ________ genes flow of _______ between two or more populations Occurs in Two Phases physical • Geographic isolation: happens first; ________ isolation of populations for a long period • Reproductive isolation: ________ and natural mutations selection in geographically isolated populations lead to inability to produce viable offspring when members of two different populations mate

Adapted to cold through heavier fur, short ears, short legs, and short nose. White fur matches snow for camouflage. Arctic Fox Northern population Early fox population Different environmental conditions lead to different selective pressures and evolution into two different species. Spreads northward and southward and separates Gray Fox Southern population Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Fig. 4 -10, p. 91

• For species that reproduce _______, slowly speciation is hard to document and study • Humans sometimes control the process with artificial _________ selection • Humans select desirable traits (in wheat, fruit, dogs, etc. ) and use ________ breeding or selective crossbreeding to generate populations with the desired traits

Desired trait (color) Cross breeding Pear Apple Offspring Best result Cross breeding New offspring Desired result Fig. 4 -C, p. 92

Science Focus: Changing the Genetic Traits of Populations • Genetic engineering can be used to ______ speed up our ability to manipulate genes • Alteration of an organism’s genetic material by adding, deleting, or changing segments of its DNA • Consider • • Ethics Morals Privacy issues Harmful effects Human growth hormone gene

Extinction is Forever • Another process affecting the number and types of species on earth is extinction • Biological extinction…a process in which an entire species ________ to exist ceases • Local extinction…a species becomes extinct over a large area, but not _________ globally • Endemic species …found only in one area • Exist on islands other unique areas • Particularly vulnerable to extinction because they are migrate unlikely to ______ or adapt in the face of rapidly changing environmental conditions

Golden Toad of Costa Rica, Extinct Lived in Costa Rica’s protected ____ high altitude preserve, but may have become extinct when its habitat dried up Fig. 4 -11, p. 92

Extinction is Forever • Background extinction: typical ____ rate of low extinction • Natural process rise • Mass extinction: significant ______ in extinction rates above the background level • often catastrophic, widespread, global events • 25 to 95% of all species are wiped out world wide in a few million years or less 3 5 • At least ______, probably ______ mass extinctions

Review Questions • How has plate tectonic movement affected populations over time? Populations have been exposed to different climates Volcanoes/earthquakes • What is the difference between geographic and reproductive isolation? Physical isolation Mutations that lead to an inability to produce viable offspring

Review Questions • What is the difference between artificial selection and genetic engineering? Altering DNA to change traits Selecting/breeding desirable traits “slow” • Why are endemic species vulnerable to extinction? They live in remote locations and may have difficulty migrating or adapting to environmental changes