Chordates Part II Flashcards Preview

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Flashcards in Chordates Part II Deck (881)
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1

aquatic mammals minimum body size

much larger than terrestrial
set by thermoregulatory demands of aquatic environment

2

larger mass animal bones

allometric growth
larger bones to support the weight, larger diameter, more robust

3

SA:V changes

as size increase, SA:V decreases
1unit cube = 6:1
2unit cube = 12:8 (1.5)
smaller ratio = lower rate of heat loss

4

sphere SA:V

SA = 4πr^2
V = (4/3)πr^3
smaller SA:V than cube of equal volume
minimize ratio for given volume

5

SA:V changes with shape

slender objects higher SA:V
ectotherms- lower MR, small, long, slender

6

consequences of size and shape variation

allometric relationships
eggs per female increase with body weight
influences survivorship and reproduction

7

evo devo

evolution and development

8

gene duplication

single genes
segment of chromosome
whole chromosome
whole genome

9

pseudogene

DNA sequences similar to normal genes but non-functional; as defunct relatives of functional genes

10

sub-functionalization

pairs of genes that originate from duplication, or paralogs, take on separate functions; ancestral gene-2 functions, new gene- 1 function

11

duplication events result in

pseudogenation
sub-functionalization
neo-functionalization

12

neofunctionalization

one gene copy, or paralog, takes on a totally new function after a gene duplication event; adaptive mutation process; one of the gene copies must mutate to develop a new function

13

functional divergence

genes, after gene duplication, shift in function from an ancestral function

14

gene duplications =

bursts of diversification

15

gene duplication, vertebrate evolution

3 episode widespread gene(ome) duplication
origin of verts, gnathostomes, teleosts

16

HOX clusters

4 in vertebrates
7-8 in teleost

17

snake venom toxins

co-opted from pancreatic origin
expanded by gene duplication
evolved under positive selection- neo-functionalization

18

Coqui development

no tadpole stage
rearrangment of development program
tail resorbed before hatching
adult characters (limbs) develop directly

19

frog with no direct development

tail growth before limb growth- gas exchange surface

20

classic neo-Darwinian 3-stage view of origin of species

mutation- new variant
selection- altered frequency/fixation ('new population')
reproductive isolation- new species

21

altered 4-stage evolved view of origin of species

mutation-- new gene
re-programming- new ontogeny/individual
selection-- new population
reproductive isolation-- new species

22

re-programming

developmental/embryonic/ontogenic reprogramming or repatterning

23

mechanisms of developmental reprogramming

changes in developmental programs at various stages of life
heterotopy
heterochrony
heterometry
heterotypy

24

heterotopy

∆ location of gene expression

25

heterochrony

∆ timing of ≥2 processes relative to each other
- onset, offset, rate of process
- must be allometric

26

heterometry

∆ amount of gene product

27

heterotypy

∆ kind of gene product

28

transformation grid

1 species = reference
reference points relocated in derived species to reconstruct transformed grid

29

heterochronic change

∆ rate of development to maturity
∆ time to maturity
∆ time of onset of development
alone or combined, same or different times

30

classic neotony

axolotl- retains larval features (gills, fins)