Reproduction

Question 1

Define asexual reproduction

Answer 1

A mode of reproduction where an organism can replicate itself without another organism

Question 2

Define sexual reproduction

Answer 2

A mode of reproduction involving the fusion on haploid gamete with another haploid gamete to produce a diploid zygote

Question 3

When did sexual reproduction evolve and why?

Answer 3

1.2 billion years ago meiotic sex evolved
Organisms were reproducing asexually for around 3 billion years

Sexual reproduction evolved because it increases genetic diversity so organisms are better able to adapt to changing environments

Question 4

Why do organisms reproduce?

Answer 4

To pass on their genetic material to the next generation otherwise their species would die out

Question 5

Which domains and kingdoms is asexual reproduction found in?

Answer 5

ALL domains and ALL six kingdoms of life

Question 6

what are six different types of asexual reproduction?

Answer 6

• Fission
• Budding
• Fragmentation
• Vegetative propagation
• Spore formation
• Parthenogenesis

Question 7

What kingdoms of life is sexual reproduction found in?

Answer 7

Found only in four eukaryotic kingdoms of life:

• Protista
• Fungi
• Plantae
• Animalia

Question 8

Define dioecious?

Answer 8

Individual has only male or female reproduction system.

Two individuals from different sex - male and female - and only have reproductive organs of one sex

Question 9

Define Monecious/Hermaphrodites

Answer 9

Individual that has both male and female reproductive systems

Hermaphrodites have the reproductive organs of both sexes - could either reproduce as a male or a female
Term monecious is more commonly used for plants whereas hermaphrodites is more commonly used for animals

Question 10

What is the difference between external and internal fertilizations?

Answer 10

In some species, the male and female gamete come together inside the organism (internal fertilizations) and in other species this occurs externally

Question 11

What is the difference between oviparous and viviparous species?

Answer 11

Oviparous - lay eggs
embryos develop externally
nutrients for development are in the egg
shell protects the embryo and impedes water loss

Viviparous - embryo develops internally - give birth to live young
Nutrients from mother
Mother’s body protects the embryo

Question 12

What are the differences between sexual and asexual reproduction?

Answer 12

• Asexual reproductions requires only one parent organism WHEREAS sexual reproduction requires two parent organisms
• In asexual reproduction the offspring are genetically identical to the parent therefore diseases are passed on and adapting to new conditions (evolution) is slow . WHEREAS sexual reproduction produces genetic variation in offspring therefore the species is more able to adapt to different environments or a population may be more resistant to disease.
• Asexual reproduction is time and energy efficient (don’t need to find a mate) WHEREAS sexual reproduction requires more time and energy (need to find a mate).
• In asexual reproduction the population can increase rapidly when conditions are good HOWEVER sexual reproduction is generally much slower more time/energy is required and only half of the population can reproduce

Question 13

Describe fission and what domains and kingdoms of life is it found in?

Answer 13

Fission is found in ALL domains and ALL kingdoms of life. Occurs in multicellular and unicellular organisms.

A parent cell or organism divides itself into equal parts.

1) Binary fission: Fission results in two cell or organisms
2) Multiple fission: Fission results in more than two cells (common in Protista)

Question 14

Describe budding and what domains and kingdoms of life is it found in?

Answer 14

Budding is found in ALL domains and ALL kingdoms of life. Occurs in unicellular and multicellular organisms.

A parents cell or organism divides itself into two UNEQUAL parts. A small bud (outgrowth) forms on the parent cell or organism and breaks off to form a new daughter cell or organism.

Budding can occur from anywhere in the organism or cell - but a lot of them having budding sites where it occurs more often

Question 15

Describe fragmentation and what kingdoms of life is it found in?

Answer 15

Fragmentation is found in all eukaryotic kingdoms of life. Occurs in multicellular organisms.
Not found in bacteria and archaea - because it is about multicellular organisms

Fragments of an organism can break off and then become into a new organism.

Question 16

Describe vegetative propagation and what kingdoms of life is it found in? What are some strategies of vegetative propagation?

Answer 16

Found in one eukaryote kingdom of life (Plantae)
Occurs in multicellular organisms

A new plant grows from a fragment of the parent plant

Different strategies:

• Runners
• Bulbs
• Tubers
• Suckers/ basal shoots/ root sprouts

Question 17

Describe spore formation and what kingdoms of life is it found in? What are some benefits?

Answer 17

Found in 3 eukaryote kingdoms: Protista, Fungi, Plantae
Occurs in unicellular and multicellular organisms

A parent plant forms hundreds or reproductive units, called spores, which may be stored in a case until they are released.

Benefits -

• Spores allow dispersal away from parent organism so it can colonize new locations
• Spores can grow into a new individual without requiring fertilization
• Many organisms that reproduce via asexual spores can also reproduce sexually

Question 18

Describe Parthenogenesis and what kingdoms of life is it found in?

Answer 18

Found in kingdom Animalia, only found in animals.
Occurs in multicellular organisms

An unfertilized egg develops into an individual. Usually in meiosis in a female, one egg is produced and the other 3 cells that were produced get reabsorbed into the female so that most the material goes into the egg
In parthenogenesis one of the small eggs that were going to get reabsorbed, ends up fertilizing the egg
Still a diploid organism but it is fertilized by the mother.

Most organisms that reproduce by parthenogenesis can also reproduce sexually.

Question 19

Describe what the alternation of generation is and what organisms is it found in?

Answer 19

Found in many multicellular protists, all land plants, and some fungi.

Organisms spend durations of their lifetime in the haploid and diploid stage.

Both haploid and diploid forms are multicellular (Animals don’t fit with this because are haploid form is unicellular)

The diploid form gives rise to spores
Th haploid form gives rise to gametes

Gametes can only produce the next generation or a new organism if their fuse with another gamete whereas spores do not need to fuse with another spore

Question 20

List and describe the three stages of sexual reproduction in fungi.

Answer 20

Different groups of fungi reproduce in different ways.
Most spend the majority of their time in the haploid state.

Three stages:
- Plasmogamy
Mating types fuse by plasmogamy - cytoplasm between the cells have fused but the nuclei haven’t fused - it is called a dikaryotic organism - nuclei has not fused but the cytoplasm has - mushroom
- Karyogamy
Karyogamy is the final step in the process of fusing together two haploid eukaryotic cells, and refers specifically to the fusion of the two nuclei
- Meiosis

Dikaryotic phase - cells contain two distinct nuclei

Question 21

Describe the process of reproduction in angiosperms

Answer 21

The male gamete is pollen

Pollen grain needs to land on the stigma to fertilize the ovules - for that to happen pollen needs to be transferred this can happen via abiotic or biotic factors

Question 22

What are some biotic and abiotic factors that aid pollination?

Answer 22

Abiotic - wind/rain/water (plant releases male gametes which is moved by water to the female parts)

Biotic -
Orchid attracts it pollinators by scent - mimics the scent of a female bees - tricking the bees
Flowers are well adapted to their pollinators to ensure they can attract them and hopefully that pollinator will go and visit the same species of plant so that pollination can occur

Question 23

Describe the difference between internal and external sexual reproduction in animals.

Answer 23

External fertilizations occurs in aquatic animals only WHEREAS internal fertilizations occurs in aquatic and terrestrial animals.

External fertilization is useful for sessile organisms WHEREAS internal fertilization occurs in generally motile organisms because they must find a partner.

External fertilization requires behaviors/adaptions to ensure gametes meet WHEREAS internal fertilization requires many behavior/adaptations to choose a partner and compete with rivals

For internal fertilization, organisms can be selective over who fertilizes the egg WHEREAS in external fertilization there is limited control over whose gametes fertilize the egg

Question 24

What does it mean to be ovoviviparous?

Answer 24

Some animals are ovoviviparous which is where fertilized eggs remain in the mother’s body until they hatch, but are not attached to the mother by a placenta.