EESC Geo Process in Bio Evolution

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Evolution Basics: What is biologic evolution?

The change in inherited traits in species over many generations

Evolution Basics: Why is variation important in evolution?

Variation allows organisms to adapt to changing environments

Evolution Basics: What causes genetic variation?

Mutations in DNA

Evolution Basics: What can cause mutations?

Cosmic rays, chemicals, and DNA changes

Natural Selection: What does “mutations favored by the environment” mean?

Helpful traits increase survival and reproduction

Natural Selection: How does natural selection change species over time?

Favorable traits become more common each generation

Natural Selection: Example of species with a common ancestor?

Whales and hippopotamuses

Geologic Processes & Evolution: How can continental drift affect evolution?

Continents move into different climates, changing which traits are favored

Geologic Processes & Evolution: What happens if climate change is too drastic?

Species may become extinct

Ice Ages: What is an ice age?

A long period of colder climate with expanding ice sheets

Ice Ages: When did the last major ice age occur?

About 115,000–12,000 years ago

Ice Ages: Where did Neanderthals live?

Europe and Asia

Ice Ages: Where did humans first evolve?

Africa

Ice Ages: Why may humans have survived glaciation better than Neanderthals?

Humans adapted tools and spread technology faster

Magnetic Reversals: What is a magnetic reversal?

Earth’s magnetic poles switch north and south

Magnetic Reversals: What happens before a magnetic reversal?

Earth’s magnetic field weakens or disappears temporarily

Magnetic Reversals: Why can magnetic reversals affect evolution?

Without a magnetic field, more cosmic rays damage DNA

Magnetic Reversals: What organisms may have gone extinct from magnetic field loss?

Radiolaria and some large mammals

Mass Extinction: What happened at the end of the Cretaceous Period?

About 3/4 of plants and animals became extinct

Mass Extinction: What unusual element was found at the extinction boundary?

Iridium

Mass Extinction: Why was iridium important evidence?

It suggested a meteorite impact

Mass Extinction: How did the meteorite affect life on Earth?

Dust blocked sunlight, causing plants and animals to die

Mass Extinction: What is the Chicxulub crater?

A large impact crater in Mexico linked to dinosaur extinction

Meteorite Evidence: What evidence supported the meteorite impact theory?

Osmium isotopes that are cause by meteor impacts not volcanoes , tsunami deposits, tektites, shocked quartz, and the Chicxulub crater