U4T2 - SC1.2 Radiation extinction

What does 'mya' stand for in evolutionary timescales?

• million years ago

• million years after

• many years ago

• mammals years ago

Angiosperms are:

• Non-flowering plants

• Flowing plants that produce flowers and seeds enclosed within a fruit

• Marine animals

• Reptiles

Evolutionary radiation refers to the outward, spreading pattern of diversification from a single ancestral lineage, much like waves radiating from a source.

• True

• False

When is an extinction event considered a mass extinction?

• An extinction event is considered a mass extinction when more than 75% of species disappear from Earth, as identified by gaps in the global fossil record.

• An extinction event is considered a mass extinction when only mammals are affected.

• An extinction event is considered a mass extinction when a single species goes extinct.

• An extinction event is considered a mass extinction when there is a temporary drop in population numbers.

Using the graph below, determine which mass extinctions occurred in the Palaeozoic Era

• 444 million years ago – (End Ordovician ‘O’ period)

• 375–359 million years ago – (Late Devonian ‘D’ period)

• 251 million years ago – (End Permian ‘P’ period)

• 200 million years ago – (End Triassic ‘Tr’ period)

• 66 million years ago – (End Cretaceous ‘C’ period)

Using the graph below, determine when mass extinctions occurred in the Mesozoic Era

• 444 million years ago – (End Ordovician ‘O’ period)

• 375–359 million years ago – (Late Devonian ‘D’ period)

• 251 million years ago – (End Permian ‘P’ period)

• 200 million years ago – (End Triassic ‘Tr’ period)

• 66 million years ago – (End Cretaceous ‘C’ period)

Using the graph below, determine which period had the largest total extinction rate.

• 444 million years ago – (End Ordovician ‘O’ period)

• 375–359 million years ago – (Late Devonian ‘D’ period)

• 251 million years ago – (End Permian ‘P’ period)

• 200 million years ago – (End Triassic ‘Tr’ period)

• 66 million years ago – (End Cretaceous ‘C’ period)

What is the background extinction rate?

• Estimated at 2 extinctions per million species per year

• Based on IUCN Red List data

• Number of species extinctions in each group since 1500

• How much faster extinction is happening now compared to the background rate

What is the modern extinction rate based on?

• Estimated at 2 extinctions per million species per year

• Based on IUCN Red List data, focusing on species that are extinct or extinct in the wild since 1500

• Number of species extinctions in each group since 1500

• How much faster extinction is happening now compared to the background rate

What percentage of species was lost during the End Ordovician Extinction (~444 million years ago)?

• ~80%

• ~30%

• ~50%

• ~95%