Chapter 23 - Cenezoic Earth and Life History Flashcards
Define Family homindae
Primates, includes gorilla, pan, chimpanzee, bonobo, and HUMAN
Evolution of man, 3 main steps
1) Australopithecus afarensis lived 3.9-3 M.y ago -southern ape, looks like monkey -lucy was an Australopithecus afarensis 2) Homo erectus -means "upright man" -about 1.8M.y ago to 3)Homo sapiens -evolved from homo erectus -about 800k years ago
Migration of Family homindae
-Started in east Africa, 200k years ago
how did Family homindae migrate??
Ice age at the time, sea levels allowed them to walk
First species to walk upright?
Homo erectus
Sub species of humans?
Neanderthals
- sub species of humans, cave paintings in france
- interbreeding to form sub species
- different races are different types of species
Are humans getting smarter?
no
Conditions of a sun to support a planet to have life?
Age, mass, metal content, location, stability, multiplicity,
Condition of another planet to have life; suns age
can’t be younger than 3 b.y b/c creates time frame long enough for life to endure life
Condition of another planet to have life; sun’s mass
no larger than 1.5x sun’s mass
-larger stars burn out too quickly
Condition of another planet to have life; sun’s metal content
at least 50% of suns iron concent
-enough heavy metal for rocky planets to form
Condition of another planet to have life; sun’s location
Stable location between galaxy’s spiral arms
-less likely to pass through interstellar dust and star forming regions, causing climate change
Condition of another planet to have life; sun’s stability
Cannot be a variable star
-such stars are prone to flares ad changes in brightness
Condition of another planet to have life; sun’s multiplicity
Stars in multiple star system must be very close together or very far apart
-otherwise, stars gravity will interfere with the orbits of planets suitable for life
Where have we found water?
Encladus (moon of Saturn), Europa (moon of Jupiter), Mercury, mars
What is drakes equation??
Drakes equation estimates # of alien civilizations we could detect. Recent discoveries of numerous planets in milky way have raised our odds
How likely is extraterrestrial life?
Arthur c. Clark -> the fact that we have not yet find extraterrestrial life is the is the fact that our methods of detection is primitive.. Just because we havent found it means that our methods are just not right