Other Minds - Chapter 1

Question 1

What is an arthropod?

What are the 4 main arthropod groups?

Answer 1

• an invertebrate with paired joint appendages, an exoskeleton and a segmented body

1) insects
2) myriapods (eg. centipedes and milipedes)
3) arachnids (eg. spiders, mites and scorpions)
4) crustaceans (slater, prawns, crabs)

Question 2

Invertebrate definition

What might they have instead?

Answer 2

animal that DOES NOT have a backbone

• instead may have exoskeleton protects like armour

Question 3

Vertebrate definition + where it comes from

5 examples of vertebrates

Answer 3

animal with a spinal cord surrounded by cartilage or bone

(word comes from ‘vertebrae’ - bones that make up the spine)

• birds, fish, amphibians, reptiles, mammals

Question 4

Palenteology

Answer 4

branch of science concerned with fossil animals and plants

Question 5

Era

Answer 5

Press the pale button to message the centre

Precambrian (era of early life)
Paleozoic (ancient life)
Mesozoic (age of reptiles and gymnosperms)
Cenozoic (age of mammals and angiosperms)

Question 6

Period

Answer 6

Camels often sit down carefully, perhaps their joints creak

Cambrian
Ordovician
Silurian
Devonian
Carboniferous
Permian
Triassic
Jurassic
Cretaceous

Question 7

Epochs of the Cenozoic era (now)

Answer 7

Put eggs on my plate, please honey

Paleocene
Eocene
Oligocene
Miocene
Pliocene
Pleistocene (ICE AGE!!)
Holocene

Question 8

Order of three main PERIODS mentioned in the book?

Answer 8

ediacaran —> cambrian –> ordovician ……

Question 9

Explain the positioning of the Cambrian period?
How long did it last?
What was life like before the Cambrian period and during?

Answer 9

The Cambrian period was the first geological time period of the Paleozoic era. It was preceded by the Ediacaran period and it was followed by the Ordovician period.

The Cambrian era lasted 55.6 million years.

Precambrian = majority of living organisms were small, simple and unicellular
Millions of years immediately preceding Cambrian = multicellular, complex organisms gradually becoming more common
During Cambrian = Cambrian explosion (rapid diversification of life forms)

Question 10

What animal fossil suggests fish evolved into four legged animals?

Answer 10

Tiktaalik fossils
aquatic animals during Devonion period - scales and gills - flattened head of crocodile - unusual fins (which may have developed into 4 limbs).
Close relative of the ancestors of tetrapods (4 legged land vertebrates)

Question 11

4 examples of well known cephalopods

Answer 11

• cuttlefish
• squid
• octopus
• nautiluses

Question 12

How many years ago was earth formed?

When did life first form on earth?

Answer 12

5.45 billion

Around 3.8 billion years ago. (So 2 billion years after earth formed)

Question 13

What did fossils NOT have before the Cambrian era and what does this suggest?

What did fossils HAVE during the Cambrian era and what does this suggest?

Answer 13

• eyes, claws, spikes, shells: suggests there was no predation and organisms lived alone
• eyes, claws, antennae: suggests organisms started interacting with each other

Question 14

What was the name of the asteroid that hit earth, when did it hit?

Answer 14

• chicxulub crater

- 66 mya (dinosaurs became extinct 65 mya)

Question 15

4 points of signalling and communication & how this led to multicellular organisms? (about recepting etc)

Answer 15

• One part must be receptive and the other active, establish connection between the two.
• Possibility for coordination between
  cells emerges when the same chemicals are sensed and produced (social behaviour)
• Signaling and communication – cells making chemicals to be perceived and responded to
• multicellular organisms: cells means to sense external environment become means to sense what another cell is doing inside the same organism

Question 16

Talk about E. coli sensing

Answer 16

• Can sense/smell, reacts by moving towards or away from concentrations of chemicals.
• Because bacterium is so small the sensors alone can give no indication of the direction that the bad or good chemical is coming from. Instead the bacterium focuses on whether the concentration of the chemical is increasing or decreasing.
• One mechanism registers the conditions right now, another records conditions a few moments ago.
• run: straight line. tumble: changed direction quickly
• input system and output (flagella) system

Question 17

Quorum sensing

Answer 17

the ability to detect and to respond to cell population density by gene regulation.

Question 18

How did multicellular organisms most likely arise?

Answer 18

• not the meeting of two lone cells

RATHER

• two cells which did not separate properly during cell division

Question 19

sponge –> comb jelly –> multicellular

Explain

Answer 19

• ball of cells on seabed began feeding by filtering water through channels in their bodies: sponge evolved
• ball of cells evolved into comb jellies (ctenophores) that lived suspended in water
• if a new multicellular organism is to arise the cell must be able to signal and communicate (importance of sensing, communication, social evolution)

Question 20

What sometimes forms a brain?

Answer 20

a mass of cells concentrated together

LINK - gut is a brain (mass of unicellular bacteria and microbes oooh)