Geological time + continental drift

What are the four major drivers of evolution?

The four major drivers of evolution are:

1. bolide impact/meteor

2. climate change

3. continental movement (which can be caused by plate tectonics / is associated with earthquakes

4. vulcanism (eruptions)

What are the four major CONSEQUENCES of these evolutionary drivers?

1. large scale migrations - species can be driven to migrate by evolutionary pressures

2. speciation - different species can form/branch off from existing species

3. mass extinctions - species can go extinct if they don’t evolve in time

4. adaptive radiations - rapid (VERY FAST) evolution of diverse species from a common ancestor

What is the geological timescale? Specifically, what is it defined by?

The geological timescale is defined by changes in FLORA (plant life) and FAUNA (animal life). These changes happen because of global events. One example of a global event changing life on earth is continental drift, or the movement of the tectonic plates.

What is the late Cambrian? Which era does it mark the beginning of?

• it is the beginning of the Palaeozoic era

• This is when we started seeing unicellular —> multicellular organisms. This was known as the Cambrian explosion, where MANY species appeared VERY SUDDENLY.

• Trilobites - an umbrella term for a bunch of arthropod species (ex. crustaceans) - came about in this period.

What are chordates? What geological timescale (period) did they first come about?

Chordates belong to the phylum Chordata, which include ALL vertebrates and some invertebrates. They are named chordates because they have a notochord, which is a developmental thing (serves as the scaffold for spine development in embryos).

The first chordate came about in the Cambrian.

What is the middle Ordovician period?

This is one of the COLDEST times in history, when ice was everywhere. This was also when the first vertebrates appeared, like jawless fish - the ancestors of the jawless fish include lampreys and hagfish.

What is the early Devonian period?

This was the age of fish (where bony fish appeared) and also the age of the first amphibians (tetrapods, or four-legged animals), and also where Pangea was beginning to form.