lecture 3 brief hist. life on earth

Question 1

what are the three domains of life

Answer 1

bacteria, eukaryotes and Archaea

Question 2

what are the six kingdoms

Answer 2

archaea, bacteria, protists, fungi, plantae, animalia

Question 3

wha are the four kingdoms from eukaryotes (domain)

Answer 3

protists, fungi, plantae, animalia

Question 4

what are archaea

Answer 4

prokaryotes that lack a peptidoglycan cell wall, e.g. extreme halophiles, thermophiles and methanogens

Question 5

what are bacteria

Answer 5

– prokaryotes with a peptidoglycan cell wall, e.g. cyanobacteria, soil bacteria, nitrogen-fixing bacteria and pathogenic bacteria

Question 6

what are protists

Answer 6

eukaryotic, primarily unicellular organisms, (algae are multicellular) They are
heterotrophic or photosynthetic organisms eg. amoebas and paramoecia.

Question 7

what are fungi

Answer 7

eukaryotic, mostly multicellular, (yeasts are single celled). They are heterotrophic,
usually nonmotile, with chitin cell walls – eg mushrooms.

Question 8

what are plantae

Answer 8

eukaryotic, multicellular, non-motile, usually terrestrial, photosynthetic organisms
such as trees, grasses, and mosses.

Question 9

animalia

Answer 9

• eukaryotic, multicellular, motile, heterotrophic organisms such as sponges, spiders, newts, penguins, and humans.

Question 10

what was the first form of life? when did it appear and when was it dominant

Answer 10

Prokaryotes were the first forms of life – they appeared 3.8 billion years ago. They were the
dominant form of life between 3.5 and 2 billion years ago

Question 11

when did cells with nuclei come about

Answer 11

1.7 billion years ago

Question 12

what happened with cyanobacteria around 3.5 billion years ago?

Answer 12

They are oxygen-generating algae.
These photosynthetic algae:
Raised atmospheric oxygen levels
(over >billion years!)
Enabled the ozone layer to form
Protected the Earth from U. V. rays

Question 13

what evolved 1.5 -2.1 billion years ago

Answer 13

eukaryotes

Question 14

what are eukaryotes

Answer 14

Eukaryotes are larger and more complex than prokaryotes. They have a nucleus, chloroplasts and mitochondria. It is thought that these evolved as a result of endosymbiotic relationships between bacteria

Question 15

what is the pathway of early eukaryotic evolution

Answer 15

Ancestral prokaryote
• Infoldings of plasma membrane
• Engulfing of aerobic heterotrophic prokaryote
• Engulfing of photosynthetic prokaryote
• Endosymbiotic relationships between bacteria

Question 16

how did evolution of multicellular eukaryotes occur?

Answer 16

y single-celled eukaryotes living in association
with each other. This lead to the development of specialised cells. Most organisms were aerobic,
and sexual reproduction was generally well developed, and this generated variation and lead to an
increase in the rate of evolution

Question 17

fusion of gametes lead to——which generates——-

Answer 17

genetic reecombination

variation, enabling evolution

Question 18

what eukaryotes evolved next 600 million years ago

Answer 18

jellyfish and worms

Question 19

what ocurred 570 million years ago

Answer 19

early cambrian period

Question 20

what occured 500 million years ago

Answer 20

land colonised by plants fungi and animals

Question 21

what did the movement from aquatic to terrestrial require

Answer 21

numerous adaptations

Question 22

when were most of the orders of modern mammals established?

Answer 22

50 to 60 million years ago

Question 23

when did human lineage diverge from other primates

Answer 23

5-6.5 million years ago

Question 24

what is a good example of adaptive radiation

Answer 24

A
good example of adaptive radiation is seen in Darwin’s finches (see below). The original ancestral
finch colonised the Galapagos Islands. In the absence of competition from other birds, the finches
evolved by natural selection (and adaptive radiation) to occupy various niches, according to the
available food supply.

Question 25

what is the genearal thing to be taken from this lecture

Answer 25

organisms react with the environment and they shape eand impact each other