3. One True Tree of Life

Question 1

What is an evolutionary tree?

Answer 1

part of the tree of life, a graphical representation of evolution (like a family tree)

Question 2

What do the lines in an evolutionary tree represent?

Answer 2

living species as the branches and a common ancestor as the trunk

extinct species make up the connection between the living species and common ancestors

Question 3

Did humans evolve from chimpanzees?

Answer 3

no, we just share a common ancestor

Question 4

What is a common phrase said to right a misconception about evolutionary trees?

Answer 4

“evolution is like a bush, not a ladder”

Question 5

How does Darwin’s theory relate to the Tree of Life?

Answer 5

living species are descended from extinct ancestral forms (can tell through bones)
- called descent with modification by Darwin
- he thought that life was really old - 3.7 billion years we know now

Question 6

What is the “One True Tree of Life”?

Answer 6

the one correct way in which all living and extinct species are linked (not arbitrary, there is only one way)

we don’t know this yet, but there are many good working hypotheses (is the science of taxonomy)

Question 7

What does each element of a tree represent in evolution?

Answer 7

roots = common ancestor

green leaves = living species

wood = extinct forms

branches = descent

Question 8

What are some positives of using a tree as a metaphor for evolution?

Answer 8

branching indicates descent, an easily visualized representation

Question 9

What are some negatives of using a tree as a metaphor for evolution?

Answer 9

roots grow too (not accounted for in the metaphor), only one arrangement of all of the leaves

Question 10

What would be a better metaphor for evolution?

Answer 10

a mobile

Question 11

What different species groups are humans a part of?

Answer 11

great apes, primates, mammals, vertebrates, animals, species on earth

Question 12

What percentage of time have humans been around for the duration of life on earth?

Answer 12

0.025%

Question 13

How does an ecologist (someone concerned with evolution) view humanity?

Answer 13

humbly, humans are very new and only 1 of millions of species

Question 14

What is the most dominant species on earth today?

Answer 14

humans, despite being new

Question 15

Why is the “march of progress” an inaccurate representation of evolution?

Answer 15

implies there was a ladder toward humans

leaves out a lot of evolution

depicts a white man as the end of the evolution

Question 16

Is there progress in evolution?

Answer 16

only in the narrow sense of creating adaptations within species

Darwin didn’t use the term evolution because it implies progress → used “descent”

Question 17

Is there progress between species?

Answer 17

Natural selection acts on individuals within populations – differential reproductive success

No way of ranking two species

Higher vs. lower vertebrates: NO

Ladder-like thinking: NO

NS (nervous system?) operates within populations: YES

Question 18

How do we rank individuals of species in western society?

Answer 18

our rankings are positively related to: evolutionary relatedness to us, self-aware/bright social species, pets, cute animals

negatively related to: dangerous animals, ugly animals, seemingly abiotic organisms

Question 19

How are species ranked in Indigenous culture?

Answer 19

no rankings, humans are often referred to as the younger brothers of creation, we are meant to learn from our elders (older species), even abiotic organisms have spirits