Evolution - Speeds

A species of butterflies remains unchanged for millions of years, showing no significant evolutionary changes in the fossil record. What pattern of evolution is this?

Fossil evidence shows that a species of mollusks remained the same for millions of years, followed by a sudden change in shell shape over a relatively short time. What evolutionary pattern does this represent?

Over the course of millions of years, a species of reptiles gradually developed longer legs, with no sudden jumps in the fossil record. What type of evolutionary change is this?

Horses evolved from small, multi-toed ancestors to large, single-toed animals over millions of years with a slow and steady accumulation of changes. What pattern of evolution is this?

A species of fish found in a deep-sea trench has remained morphologically the same for over 50 million years. What type of evolutionary pattern is this?

A small population of birds on an isolated island experiences rapid evolutionary changes due to environmental shifts, followed by long periods of stability. What pattern does this describe?

The fossil record of trilobites shows that they remained unchanged for millions of years before disappearing. What pattern of evolution is this?

Fossils of certain marine invertebrates suggest that changes in shell size and shape occurred very gradually over millions of years. What does this represent?

A population of frogs remains unchanged for thousands of years but, after a major climate shift, evolves rapidly into multiple new species. What is this an example of?

Fossil evidence indicates that a species of insects has existed for 100 million years without significant structural changes. What does this suggest?