Module 2B

Question 1

The amazon molly

Answer 1

• first vertebrate to which unisexuality was recognised
• all are females
• produced from hybridization of sailfin and shortfin molly (DNA derived from mother)

Question 2

Hybridization

Answer 2

cross breeding between species

Question 3

How does Parthenogenesis occur in amazon mollies?

Answer 3

female receives sperm transfer from a male ailfin or shortfin molly
- not sexual reproduction because the sperm does not fertilize the eggs, only serves to activate diploid eggs to develop offsprings of female that are clones (sperm dies)
- distributional range is limited to where there is sailfin or shortfin mollies

Question 4

Are parthenogenetic diploid species homozygous or heterozygous?

Answer 4

• all females are homozygous and so are their offspring
• genetic variation can still occur by mutation

Question 5

Apromixis

Answer 5

• asexual reproduction without fertilization (in plants)
  Ex. dandelions (seeds reproduce without pollination

Question 6

Sexual reproduction

Answer 6

• production of new individual by joining of gamete to form a zygote by fertilization (plants and animals)

Question 7

sexual reproduction for plants:

Answer 7

• self fertilization and cross fertilization by pollination
• pollen gets carried by wind or birds to fertilize eggs

Question 8

sexual reproduction for animals:

Answer 8

by cross-fertilization (mating with another individual)
- external fertilization: releases egg and sperm into environment at the same time
- internal fertilization: egg and sperm come together within one individual

Question 9

Hermaphroditic

Answer 9

Individual contains both male and female sex organs
Ex. flatworms (mainly cross-fertilization but rarely self fertilization)

Question 10

Sequential hermaphroditism

Answer 10

A process in an individual changing sex’s later sometime from being born and beginning life as one sex

Question 11

How does sequential hermaphroditism work in clown fish?

Answer 11

• Individuals begin life as males and then later change to become females
• single mating pair consists of large dominant female and small male and smaller non-breeders
• loss of dominant female provides stimulus for male partner sex change to female and non-breeder into a breeding male

Question 12

Sexual reproduction for bacteria, protists, and fungi

Answer 12

production of new individuals by exchanging genetic material from two individuals of different mating types (conjugation)
- no separate sexes with “male” or “female” reproductive structures
- different mating types (+/-)

Question 13

Conjugation

Answer 13

two organisms fuse along a common surface and exchange genetic material (bridge-like connection or direct contact)
- no increase of number of individuals

Question 14

Disadvantages and advantages of asexual reproduction:

Answer 14

Advantages:
- large number of offspring (produce rapidly)
- only one individual required

Disadvantages:
- little or no genetic variation

Question 14

Disadvantages and advantages of sexual reproduction:

Answer 14

Advantages:
- increased genetic variation
- enhances reproductive success in changing environments

Disadvantages:
- locate a mate

Question 14

Why are viruses not living organisms?

Answer 14

• do not contain all 4 biomolecules
• does not have a cellular structure (basis for life)
• unable to replicate outside of a living system (no reproduction)
• not capable of independent metabolism

Question 15

Viruses

Answer 15

Infect cells of living organisms (cause disease)
- smaller than bacterium
- consists of genetic material (nucleic acids, DNA)
- contained within a capsid

Question 15

Viroids

Answer 15

Infectious particle of plants
- does not have cellular structure
- depends on enzymes of a plant for replication
- lack proteins
- consists of RNA but do not code for any proteins

Question 16

Prions

Answer 16

non-living entities
- more simple and are bits of protein
- no DNA or RNA
- no celular structure
- cause of BSE (mad cow disease)

Question 17

What is the “matrix of life”?

Answer 17

H20: 60% body mass of animals and more than 95% of some plants
- suspends red blood cells to carry oxygen to cells (animals)
- for electrolyte and nutrients needed by cells
- carries metabolic waste from cells
- maintains osmotic regulation in cells
- transport of molecules in/out of cells

Question 18

Hypertonic vs Hypotonic:

Answer 18

Hypertonic: greater concentration of salt (water moves towards it)
Hypotonic: lower concentration of salt

Question 19

Counter-current exchange

Answer 19

heat moves from warmer to colder temperature
- minimizes water loss
- used by camels by it’s nasal turbinates highly folded

Question 20

How do camels adapt?

Answer 20

• pads on feet for walking on hot soft sand and toes spread for better grip
• long legs for carrying load on back and body father from the ground
• hard fat layer of skin and leathery patches on knees protects from heat when sitting
• long thick eye lids with double eyelashes to prevent from sand
• thick split lips to eat thorny desert plants
• hump stores area for fat supply to avoid dehydration (convert fat into water)

Question 21

How do camels regulate their body temperature?

Answer 21

• as temperature increases the camel raises its body temperature to prevent sweating (water loss)
• warmer temperature than environment as heat flows from higher to lower
• declines during night so there’s no excessive cooling and the thick fur insulates body

Question 22

How many weeks can camels go without drinking water?

Answer 22

2 weeks - obtain enough to maintain body temperature - rehydrate very quickly

Question 23

What happens to the camels body temperature when it is dehydrated?

Answer 23

reduced capability of maintaining homeostasis

Question 24

Diffusion

Answer 24

movements of particles going from high to low