Lecture 11 - Macroevolution Flashcards Preview

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Flashcards in Lecture 11 - Macroevolution Deck (35):
1

What is irreducible complexity?

-a system composed of several parts that all contribute to a function
-removal of any part causes the system to cease functioning

2

What is the rebuttal to irreducible complexity?

-pieces of complex systems often have functions of their own
-"making a simpler mouse trap"

3

What is an example of a rebuttal against reducible complexity argument?

-bacterial flagellum (basal body)
-made of parts that could serve other functions
-can function if parts are missing

4

What is another example against reducible complexity?

-eyes

5

What does "the evolution of new species is rarely if ever observed" mean as a critique of evolution?

-we never see it happen

6

What are 2 major rebuttals against the claim that new species are never observed?

1. too little of time to observe origin of new species (<0.0066% of biological history)
2. we HAVE observed origin of new species
(in lab, polyploidization, naturally without polyploidization)

7

What is punctuated equilibrium?

-periods of evolutionary stasis interspersed by major change
-(nothing, then sudden change)

8

punctuated equilibrium is not explained by ___________

Darwinian Theory

9

What did Darwin's theory believe in instead of punctuated equilibrium?

gradualism

10

What are 3 rebuttals to punctuated equilibrium?

1. punctuations that appear abrupt in fossil record may take tens of thousands of years
2. periods of apparent stasis may fail to give a true impression of biochemical changes not detectable in fossil record
3. slight genetic changes may result in phenotypic changes

11

Sometimes changes at a single ______ can cause _______

gene, speciation

12

In many cases, what is the origin of large phenotypic changes?

evolution of genes controlling development (evo-devo)

13

What is heterochrony?

changes in rate and timing

14

What does heterchrony include?

-changes in relative growth rates of different body parts (allometry)
-changes in timing of reproductive vs. somatic development

15

What does relatively rapid reproductive growth result in?

paedomorphosis

16

What is paedomorphosis?

sexually mature adults with juvenile morphology

17

What is allometry?

changes in relative growth rates of different body parts

18

Changes is allometric growth lead to differences between what 2 species?

human and chimp adult skulls

19

What is an example of a paedomorphic pet? What are its qualities?

-dogs
-relative to ancestral wolves domesticated dogs have:
1. softer fur
2. larger head/eyes
3.droopier ears
4. more submissive behavior
5. shorter muzzle

20

Alteration in ______ controlling the placement and organization of _____ _______ cause major _______ change

genes, body parts, evolutionary

21

what are homeotic genes?

genes that control body plans

22

How do homeotic genes work?

They control the developmental fate of groups of cells

23

What are Hox genes? What do they provide?

-products of one class of homeotic genes
-positional information in animal embryos

24

What is an example of Hox genes controlling evolution?

-fish fins to tetrapod limbs
-suppresses leg formation in insects but not crustaceans

25

What are 5 hallmarks of macroevolution?

1. evolution is not goal oriented
2. evolution is not a ladder from simple to complex
3. novel features often arise through intermediate stages (each serving a function)
4. evolution recycles features and put them to new uses
5. evolution leaves baggage behind

26

What does it mean that evolution is not goal oriented?

-mutations are random
-selection "chooses" mutations that increase reproduction/survival
-evolution gropes blindly in many directions at once

27

What was the old view of evolution? Ladder or tree?

ladder from one-hole to two-holes

28

What was one of the first organisms that was discovered having a complex digestive system?

ctenphora

29

All organisms evolved from a ______ _________

common ancestor

30

What is an example of novel features arising through intermediate stages?

partial wings (they can be adaptive)

31

What is an exaptation?

many characters evolved for purposes other than those for which they are currently used

32

What are 3 examples of exaptation?

1. feathers evolved for insulation, co-opted for flight
2. protein used for cell adhesion in multicellular organisms first evolved in singled celled choanocytes
3. ancient angae had genes for survival on land before they left for water and colonized land

33

What are 3 examples of human evolutionary baggage?

1. appendix
2. trachea
3. blind spot

34

What are the 3 major criticisms of macroevolution?

1. irreducible complexity
2. no observations of speciation
3. punctuated equilibrium inconsistent with Darwin

35

What are the 2 roles of "evo-devo" in driving large changes?

1. changes in rate and timing
2. changes in spatial pattern