The History of Life

These flashcards cover key concepts, events, and definitions outlined in the lecture notes on the history of life.

What time period is marked by the Cambrian explosion?

541-530 million years ago, marked by rapid diversification and emergence of most modern animal phyla.

What are stromatolites?

Layered rocks that form when prokaryotes bind thin films of sediment together.

Around what time did the first eukaryotes appear?

Approximately 1.8 billion years ago.

What significant event is referred to as the 'oxygen revolution'?

The period when oxygen produced by photosynthesis began to saturate water and fill the atmosphere.

What is endosymbiotic theory?

The evolutionary theory that eukaryotic cells originated from prokaryotic cells engulfing one another.

Which organelle is the site of aerobic respiration?

Mitochondria.

Which organelle is responsible for photosynthesis?

Chloroplasts.

What major evolutionary event occurred around 3.7 billion years ago?

Origin of life with the earliest direct evidence, which are stromatolites.

What are the defining features of eukaryotic cells?

Eukaryotic cells have a membrane-bound nucleus and organelles.

What is a Niche in ecological terms?

The specific environmental and ecological conditions available for life to use.

When did multicellular organisms first appear?

Around 1.2 billion years ago.

What do we call the event when dinosaurs and many other species became extinct at the end of the Cretaceous period?

The mass extinction event at the end of the Cretaceous.

What organisms dominated the landscape during the Mesozoic era?

Dinosaurs and gymnosperms.

When did flowering plants (angiosperms) first appear?

During the Cretaceous period.

What are the two main groups of prokaryotic organisms?

Bacteria and Archaea.

What evidence supports the endosymbiotic origin of mitochondria and chloroplasts?

1. Similarity of inner membranes to prokaryotes, 2. Similar enzymes and transport systems, 3. Replication by a splitting process, 4. Circular DNA structure.

When did the first multicellular eukaryotes appear in the fossil record?

Approximately 600 million years ago.