Cosmic History

Question 1

physical evolution

Answer 1

expansion of the cosmos suggests that the universe is about 13.8 billion years old and that its early state was extremely dense, hot and rapidly expanding = big bang

strongly supported by many other observations

• cosmic microwave background
• the abundance of simple elements
• the age of the oldest stars
• the spatial distribution of galaxies

gravity formed clumps of dust which became stars and planets

Question 2

biochemical evolution

Answer 2

conditions on some planets are such that complex molecules can form

this molecule splits into two smaller parts, each of which complements itself back to the original molecule = DNA

natural selection
- random mutations that occur during the replication
- selective survival of the
offspring that are best adapted to their environment

Question 3

cultural evolution

Answer 3

humans have the unique capacity to use sophisticated language to exchange ideas between each other and adapt their behaviour according to these learned ideas

memes

he reason that humans evolved from hunters and gatherers to highly complex modern societies, without much significant genetic change