Multicellularity and Sex

Question 1

multicellularity

Answer 1

usually means different cell types that interact with each other to build organism structure

Question 2

sex

Answer 2

involves change in ploidy during life cycle

Question 3

which clades are multicellular

Answer 3

fungi, animals, red algae, land plants, brown algae

Question 4

is multicellularity an inevitable evolutionary transition?

Answer 4

nah bro

Question 5

earliest multicellular organism date

Answer 5

580 mya (prob animal)

Question 6

costs and benefits to multicellularity

Answer 6

costs- energy and physiological probs (like diffusion across many cell layers)

Benefits- persistence and dominance in habitat
-structural complexity enables multiple solutions to complex problems

Question 7

what was the atmospheric requirement for multicellularity?

Answer 7

oxygen

Question 8

plant cell adhesion

Answer 8

plasmodesmatas

Question 9

animal cell adhesion and communication

Answer 9

cell junctions

Question 10

chem signaling and electrical signaling

Answer 10

usually one cell will secrete a hormone that’ll bind to receptors on another cell

electric potentials (e.g. mimosa plant)

Question 11

is sex an old or a new eukaryotic trait?

Answer 11

Sex was in the early eukaryotes

Question 12

do prokaryotes have sex?

Answer 12

nah bro

Question 13

2 processes in sex

Answer 13

meiosis and fertilization

Question 14

4 steps differing meiosis from mitosis

Answer 14

1. pairing of homologous chroms.
2. recombo of non-sis chromatids
3. suppression of sister-chromatid separation during first division
4. no chrom. replication during 2nd meiotic division

Question 15

anisogamous species

Answer 15

• gametes aren’t identical
• some have flagellated gametes
• include oogamous ones
• plants, animals, and many protists

Question 16

oogamous

Answer 16

sperm producer is male and egg producer is female

Question 17

isogamous

Answer 17

morphologically identical gametes (lots of protists and fungi)

Question 18

chromosomal sex determination

Answer 18

1. Sex chromosomes: homogametic (xx) and heterogametic (xy)

2. Ploidy level: haplodiploid where diploid=f and haploid=m

Question 19

environmental sex determinations

Answer 19

1. temp during development

2. population-density chems during dvlpmnt

Question 20

Dioeciou/Gonochoristic

Answer 20

one sex only throughout life–> male of female

Question 21

Hermaphrodite/ Monoecious

Answer 21

both sexes at once –> in plants–> depends on how flowers are made

Question 22

sequential hermaphrodite

Answer 22

both sexes at dif times in life

Question 23

example of haplodiploidy

Answer 23

bees

Question 24

can something be oogamous and hermaphroditic at the same time?

Answer 24

yeah bro

Question 25

parrotfish

Answer 25

protogynous

• start female (usually)
• terminal phase males develop from females
• turn red

Question 26

clownfish

Answer 26

• protandrous
• start male
• big dom male becomes female
• she only mates with 2nd biggest

Question 27

pros and cons of hermaphrodite

Answer 27

pros: ease of finding sex partner, whether yourself or someone els

cons: offspring’s alleles only come from you
- loss of heterozygosity
- more deleterious recessive alleles

Question 28

how do hermaphrodites avoid self-fertilization?

Answer 28

earthworms only exchange sperm with other individuals

plants often have self-recognition proteins that prevent self-gametes from growing

Question 29

Can eukaryotes reproduce asexually

Answer 29

yep

Question 30

describe the ploidy changes in asexual reproduction

Answer 30

there aren’t any

Question 31

parthenogenesis (animal)/ apomixis (plants)

Answer 31

usually female ofspring are formed from egg of mother –> genetic clones

-dandelions, nematodes, amphibians, sharks, etc…

Question 32

vegetative reproduction

Answer 32

body pieces of parent become free liing

• clones
• ex: medusae from hydrozoan animals and alot of plants

Question 33

marbled crayfish (p. virginalis)

Answer 33

triploid females make female young parthenogenetically

-only decapod crustacean that can do that

Question 34

Dominant stages are haploid

Answer 34

haplontic life cycle with zygotic meiosis

Question 35

dominant stages are diploid

Answer 35

diplontic life cycle with gametic meiosis

Question 36

alternation of haploid and diploid life stages

Answer 36

• alternation of generations

- diplohaplontic life cycle with sporic meiosis