Extinction

Question 1

Current Mass Extinction

Answer 1

Humans are the primary cause of the current mass extinction, primarily due to habitat destruction, pollution, climate change, and overexploitation. Studying this extinction helps us understand its effects and develop strategies for conservation.

Question 2

Permian-Triassic Mass Extinction

Answer 2

Occurred ~250 million years ago, wiping out ~90% of species. Possible causes include a meteorite impact and massive volcanic eruptions. Key victims: trilobites. Survivors: therapsids and early reptiles, leading to mammals and dinosaurs

Question 3

Krakatau Eruption (August 26, 1883)

Answer 3

The eruption destroyed the island of Krakatau, causing massive environmental changes. Biologists study this event to understand ecological recovery and species recolonization after extreme disturbances

Question 4

Post-Permian-Triassic Survivors

Answer 4

Mammals and dinosaurs emerged as dominant land vertebrates after the Permian-Triassic extinction, remaining so for 150 million years

Question 5

Cynodonts

Answer 5

Mammal-like reptiles that lived during the Triassic period. Cynodonts are significant in understanding the evolution of mammals due to their advanced jaw structure and differentiated teeth

Question 6

Neocortex

Answer 6

A part of the mammalian brain associated with higher functions like sensory perception, cognition, and spatial reasoning. It provided evolutionary advantages, enabling complex behaviors and advanced problem-solving

Question 7

Monotremes

Answer 7

Egg-laying mammals, such as platypus and echidna. They retain reptilian traits, linking them to early mammal evolution. Their reproductive method and genetic analysis highlight the continuum from reptiles to mammals

Question 8

Platypus Characteristics

Answer 8

Unique monotreme with mammalian (fur, mammary glands) and reptilian traits (egg-laying). Male platypus have venomous spurs, reptile-like walking, and specialized snouts, showcasing evolutionary links to reptiles

Question 9

Cretaceous-Tertiary Mass Extinction

Answer 9

Occurred ~65 million years ago, resulting in a 75% species loss, including dinosaurs. A meteorite triggered global ecological collapse, paving the way for mammal and bird raditation

Question 10

K-T Meteorite Crater

Answer 10

Located in the Yucatan Peninsula, Mexico, the Chicxulub crater is estimated to be 110 miles wide, caused by a 6-mile-wide meteorite

Question 11

Post-K-T Ecological Disasters

Answer 11

The impact led to massive fires, acid rain, and global cooling, severely disrupting ecosystems and causing the extinction of many species, particularly primary producers

Question 12

Human Existence & K-T Impact

Answer 12

From a scientific perspective, human evolution is partly a result of the K-T meteorite impact, as it eliminated dinosaurs and allowed mammals to diversify

Question 13

Genyornis

Answer 13

A large, flightless bird in Australia, likely extinct due to human hunting ~40,000 years ago

Question 14

Mastodons & Giant Ground Sloths

Answer 14

These species went extinct in the New World ~11,000 years ago, likely due to human hunting and climate change

Question 15

Human-Caused Extinction

Answer 15

Humans cause species extinction through habitat destruction, overhunting, and introducing invasive species

Question 16

Deforestation by 2000

Answer 16

By 2000, 50% of the world’s tropical forests were logged or burned. This rapid loss threatens biodiversity and disrupts ecosystems

Question 17

Meteorite vs Human Extinction

Answer 17

Meteorite-induced extinctions are sudden and global, whereas human-caused extinctions are gradual and often localized, driven by habitat changes and resource exploitation

Question 18

K-T Extinction Evidence

Answer 18

Evidence for a meteorite impact causing the Cretaceous-Tertiary extinction includes iridium-rich layers, shocked quartz, and the Chicxulub crater