Module 5.1

Question 1

purpose of reproduction

Answer 1

continuity of species

Question 2

Asexual reproduction

Answer 2

offspring are identical to single parent

Question 3

Sexual reproduction

Answer 3

Union of gametes from two parents to form unique offspring

all organisms apart from bacteria and archaea have sexual reproduction

Question 4

Binary fission

Answer 4

individual parent cell splits into 2

occurs in protists

Question 5

Budding

Answer 5

new individual develops from some point on parent organism

occurs in:
animals
- jellyfish, anemone, coral, hydra
- sponges
- platyhelminths (flatworms
- tunicates
fungi
- yeast
protists

Question 6

fragmentation/ regeneration

Answer 6

parent body fragments or splits and these parts develop into a fully grown identical individual

the fragments regenerate through mitosis and differentiation

Occurs in:
- sponges
- cnidarians
- platyhelminths
- Annelids
- echinoderms

Question 7

longitudinal fission

Answer 7

Entire adult body splits lengthwise

occurs in sea anemones

Question 8

Transverse fission

Answer 8

Planarians reproduce by ripping themselves into a head and tail piece that form new worms

Question 9

Diploid cells

Answer 9

has two sets of chromosomes

Question 10

Haploid cells

Answer 10

has 1 set of chromosomes

Question 11

Parthenogenesis

Answer 11

development of unfertilised eggs into adults

occurs only in females

developed offspring may be haploid or diploid

resulting offspring may be identical to mother or mot, depends on diploidy and mechanism

may happen in changing conditions (lack of available mates)

may be part of normal life cycle

Question 12

Sporulation

Answer 12

spores are tiny reproductive cells that are produced in great numbers by sporangia

spores are dispersed and travel great distance by wind

occurs in:
- fungi (moulds, mushrooms)
- Plants (ferns, mosses)

Question 13

Asexual reproduction in fungi

Answer 13

changes arise in the genome due to sexual reproduction -> if well adapted to genome, it wants to conserve it

Question 14

Sexual reproduction in fungi

Answer 14

if there is a change in environment new genetic material may have an advantage

Question 15

reproduction in plants

Answer 15

all groups in kingdom plantae reproduce sexually, some can reproduce asexually

plants have a lifecycle that alternates between haploid and diploid

Question 15

Groups of plants

Answer 15

Mosses and liverworts
ferns
gymnosperms (non-flowering plants)
Angiosperms (flowering plants)

Question 16

Vegetative propagation

Answer 16

parts of parents detach and grow into new individuals

beneficial instable environments

includes:
- cuttings
- Stem modifications
- leaf modifications

is possible by meristem tissue
- commonly found in stems, leaves, tips of roots
- contains undifferentiated cells

Question 17

Stem modifications

Answer 17

Stem modifications
- stolons -> long stems that grow along the surface (e.g., grasses)
- tubers -> swollen underground stems that store nutrients and can grow more plants e.g., potato
- rhizomes -> modified stems that typically grow horizontally underground -> roots and shoots grow at nodes in intervals of the rhizome and develop into new plants e.g., lilies, bamboo
- suckers -> new shoots arise from roots or underground stems, often after fires e.g., apples, blackberries
- artificial

Question 18

cuttings

Answer 18

cuttings
- from stems, leaves, roots, petals (rare)
- artificial

Question 19

leaf modifications

Answer 19

bulbs
- modified stem (a basal disc) that has fleshy leaves extending from it
- food storage for developing plants
- contains several buds of meristem tissue near the node where leaves are produced e.g., onions, garlic

natural

Question 20

external fertilisation

Answer 20

occurs outside female body -> generally in water
- gametes exposed to many hazards

occurs mostly in marine invertebrates, fish and amphibians

Question 21

Internal fertilisation

Answer 21

Sperm are deposited directly in (or onto) the female opening, using a penis or cloaca

fewer egg cells produced and kept protected inside the female body

fewer offspring are produced and kept protected inside the female body

occurs in:
- flat + round worms
- molluscs
- birds and mammals
- reptiles

animals can colonise land as they are not dependant on water for reproduction

Question 22

Sexual reproduction in flowering plants

Answer 22

male gamete = pollen
female gamete = ovum inside the ovary

Question 23

Pollination

Answer 23

A haploid male pollen grain lands on a female stigma

pollen grain grows tube that penetrates the stigma and carries sperm cells down to ovule

Question 24

Seeds and fruits

Answer 24

fertilised ovule develops, protected within ovary

ovule containing embryo is termed a seed and the surrounding ovary grows to become a fruit

Question 25

Internal vs external fertilisation

Answer 25

Advantages internal:
- reduces reliance on water for reproduction
- greater chance of offspring survival

Advantages external:
- many offspring can be produced
- wide dispersal of young
- is faster
- requires less energy

Disadvantages internal:
- fewer offspring produced
- requires more energy
- is slower

Disadvantages external:
- ‘hit and miss’ strategy with many wasted gametes
- often little to no parental care so few survive.