Ch11: Reproduction

Question 1

Difference between asexual and sexual reproduction?

Answer 1

ASEXUAL:
- only 1 parent
- offspring are genetically identical (placing them at risk of extinction in environmentally variable environments)
- suitable to CONSTANT environments
- Quicker population growth (less time/energy spent trying to find a mate)
- can have booms in population

SEXUAL:
- 2 parents
- offsprings genetically variable which allows for evolution + adaptation and selection
- Slower to reproduce; takes time to find a mate, and only HALF of population can reproduce

Question 2

What are the 5 types of asexual reproduction?

Answer 2

1) Fission (binary or multiple)

2) Fragmentation (echinoderms)

3) Vegetative Propagation

4) Parthenogenesis

5) Budding (fungi - single cell)

Question 3

What are the 2 kinds of sex assignments in sexual reproduction?

Answer 3

1) Dioecious: organism is either male or female reproductively

2) Monoecious: organism can reproduce (be a male OR a female) simultaneously or change sex at different points in life

Question 4

What are the 2 kinds of embryo development?

Answer 4

1) Oviparous: embryo develops and is laid externally (as an EGG)

2) Viviparous: develops internally (in parent)

Question 5

Where can embryo fertilisation happen?

Answer 5

Inside the organism OR outside (through water)

Question 6

Define fission, binary fission, and multiple fisson

Answer 6

Fission: separation of a parent organism into genetically identical daughter offspring (equal in size)

Binary Fission: a parent enlarges as the nucleus DOUBLES, and splits into genetically identical organisms (EQUAL in size)

Multiple Fission: a multinucleated organism forms cytoplasm around these nuclei and then split into equally genetically identical daughter cells (occurs under specific conditions)

Question 7

Define Budding:

Answer 7

form of asexual reproduction: an outgrowth on the parent organism that eventually splits off (NOT EQUAL in size)
- can occur in specified regions

Question 8

Define fragmentation

Answer 8

A part of the present organism is BROKEN off

This is then replenished/grown back and the fragment is able to develop into a mature, functional individual that is IDENTICAL in shape, and genetics

Can occur intentionally or unintentionally

Question 9

Define parthenogenesis

Answer 9

The development of a gamete to an identical individual

The gamete is either unfertilised (haploid) or unfertilised (diploid) (can determine sex)

Seen in sexually reproducing organisms: benefit from both reproductions under difference conditions

Question 10

Define vegetative propagation

Answer 10

Shoots + runners + suckers grow away from the parent plant, to find an environment appropriate (with resources)

Once it finds that environment: the stem fragments leave a portion to grow into a daughter plant: reduces competition + enables population persistence

Question 11

Define apomixis, what does it allow for?

Answer 11

The production of seeds without having pollination or fertilisation.

It allows for some plants (HYBRIDS) to overcome sterility

Question 12

What are artificial ways of making new plants

Answer 12

Grafting: attaching the top (scion) and bottom (rootstock of 2 plants together) to mix and produce desired traits

Cutting
Layering
Micropropagation

Question 13

Define fertilisation:

Answer 13

when 2 daughter cells fuse to form a diploid zygote

Question 13

What does alternation of generations mean?

Answer 13

organisms change between haploid and diploid stages

Question 14

Describe Plant reproduction

Answer 14

See Doc, 11a:
- Spores of plants undergo MITOSIS to produce multicellular haploids (GAMETOPHYTES)

• 2 Gametophytes pair = fertilise each other to form a DIPLOID ZYGOTE
• This zygote undergoes MITOSIS to form a multicellular diploid (SPOROPHYTE)
• The sporophyte undergoes MEIOSIS to form individual HAPLOIDS that spread out as SPORES

Question 15

Describe the fertilisation of fungi: and their sexes

Answer 15

See Doc, 11b:
Mate usually asexually of by clade: most are NOT male or female (any 2 sexually reproducing fungi can mate)

MATE:
- Fuse together to form 1 PLASMOGAMETE = cytoplasm of 2 haploid individuals fuse to form a DIKARYOTIC INDIVIDUAL (a cell that has two nuclei, one from each parent cell, and shares a single cytoplasm)

Then their nuclei fuse to form a DIPLOID;
KARYOGAMY = meiosis occurs + haploid spores are released to form mycelium + begin cycle again

Question 16

What are the benefits of monoecious reproduction?

Answer 16

• all members of a species can reproduce
• Genetic diversity can occur due to mixing of haploids

Question 17

Define angiosperms

Answer 17

Flowering parts of plants

Question 18

What are the male and female parts of a flowering plant?

Answer 18

See Doc, 11c:
Male: Pollen, Stamen, Filament

Female: Ovaries, Stigma, Style, Ovules (eggs)

Question 19

Difference between simultaneous Hermaphrodites and sequential hermaphrodites

Answer 19

Simultaneous: Produce both sperm + eggs at same time, male or female throughout their lives

Sequential: dictated by condition, social structure or age (if mates low = become missing sex)

Question 20

Benefits of dioecious reproduction

Answer 20

Guaranteed genetic variation + reduces risk of self-fertilisation

Question 21

What are the 2 different kinds of gamete investment (related to size) called?

Answer 21

1) Isogamy: gametes are equally involved in by both parents and the gametes = same size

2) Unequal gamete parental investment, meaning 1 produces a larger gamete, whilst 1 = less and therefore small gamete

usually males make = smaller gametes but more, whereas females = fewer but larger

Question 22

What are the parts of a flower

Answer 22

See Doc, 11d:
Sepals: encase + protect the plant (bottom of the flower)

Petals: protect the plant, bright to attract pollinators

Stamens: fertile flower organ, release spores that become sperm + eggs
- made of filament + anther (secrete pollen grains that develop into sperm)

Carpels: Consist of ovary, style + stigma:
- ovules = egg sacs (embryos)
- style = connects ovary + stigma
- Stigma = sticky + traps mobile sperm to reach stationary egg (ovules)

Question 23

What happens to fertilised ovules?

Answer 23

Pollintaor (sperm source) to ovules

Flowering plants: pollen is transferred from another (stamen) to stigma (by pollinators)

Then a pollen tube is formed (connect stigma to ovule) = sperm is released into ovule

Fertilisation occurs = flower develops into fruit + ovule becomes a seed

Question 24

What happens to unpollinated flowers?

Answer 24

Unpollinated flowers fail to become fruit and die