Mod 5: Critical Q1 Flashcards
How does reproduction ensure the continuity of a species
1
Q
What is the significance of reproduction?
A
To allow the survival of a species from one generation to the next
2
Q
What are the 2 types of reproduction?
A
- Asexual
- Sexual
3
Q
What is asexual reproduction?
A
- Production of identical offspring from just one parent
- Produces new offspring by mitosis
- Offspring = clones -> Genetically identical
4
Q
What are the characteristics of asexual reproduction?
A
- Occurs in unicellular organisms, fungi, plants + animals
- Another individual is not required
- Large numbers of individuals being produced relative quickly
- Advantageous in unchanging environments
- Lack of genetic variation
5
Q
What are the methods of asexual reproduction?
A
- Fission-splitting
- Budding
- Fragmentation of body parts
- Spore formation
- Vegetative reproduction in plants
- Parthenogenesis in female animals
6
Q
What is sexual reproduction?
A
- Involves mixing genetic info from 2 parents
- Union of male and female gametes (Sperm + Egg) to form unique individual
- Gametes formed by meiosis
- Reproductive system of complex multicellular organisms (Flowering plants + mammals) feature specialisation structures -> haploid gametes are produced
7
Q
What are the characteristics of sexual reproduction?
A
- Random assortment of chromosomes
- Fusion of haploid gametes -> Produce diploid zygote
- Genetic contribution of 2 parents
8
Q
What are the disadvantages of sexual reproduction?
A
- Need to fine mate
- Requires more energy
- Be limited to certain times of the year (seasonal dependence)
9
Q
What is external fertilisation?
A
When a male’s sperm fertilise a female egg outside the female’s body
10
Q
What are the characteristics of external fertilisation?
A
- Common in aquatic animals + amphibians
- Eggs and developing young don’t need to be carried inside a parent
- Thousands of eggs can be fertilised at a time
- Developing young exposed to environment
11
Q
What are the advantages of external fertilisation?
A
- Lots of offsprings can be produced
- Parents don’t need to physically meet
12
Q
What are the disadvantages of external fertilisation?
A
- Chances of fertilisation are low -> sex cells destroyed by environmental factors
- Wasted resources
- No guarantee offspring will survive
13
Q
What is internal fertilisation?
A
A male deposits sperm directly into female’s reproductive tract
14
Q
What are the characteristics of internal fertilisation?
A
- In terrestrial animals
- Mammals -> Fertilisation occurs in fallopian tubes - zygote grows and divides as it’s swept towards uterus
- Ensures gametes and developing young are protected from changes in external environment, don’t dehydrate, & provided with nutrition + suitable environment
15
Q
What are the advantages of internal fertilisation?
A
- Offspring have higher chances of survival
- Conserve resources
- Can choose their mate
16
Q
What are the disadvantages of internal fertilisation?
A
- Only produce a few offspring at once
- Parents must physically meet
17
Q
What is reproduction in plants?
A
Asexual reproduction:
- Runners
- Bulbs
- Cuttings
Sexual reproduction:
- Pollination
18
Q
What is reproduction in fungi?
A
Asexual reproduction:
- Budding + spores
- Reproduce asexually when conditions are good
Sexual reproduction:
- Spores combine to form new fungi
When conditions are bad
19
Q
What is reproduction in bacteria?
A
Binary fission:
- Cell replicates its DNA -> Cell grows to about twice its original size -> Cytoplasm divides, new membrane forms
20
Q
What is reproduction in protists?
A
- Eukaryotic, single-celled organisms
- Asexual reproduction: Binary fission + Budding
21
Q
What are non-vascular, seedless plants
A
- Bryophytes (e.g, mosses and liverworts)
- Reproduce sexually, but do not use seeds to reproduce?
22
Q
What are vascular, seedless plants?
A
- Pteridophytes (e.g, ferns and horsetails)
23
Q
What are vascular, seed plants?
A
- Non-flowering plants (Gymnosperms -> Cycads, conifers)
- Flowering plants (Angiosperms -> Grasses and wattle trees)
24
Q
What are the male reproductive parts of a flower?
A
- Stamen -> Includes the filament and anther
- Filament -> A stalk that supports anther
- Anther -> Fluffy structure that produce pollen
25
What is the female reproductive structure of a flower?
- Pistil -> Made up of the stigma, style, ovary
- Stigma -> A sticky structure where pollen gets stuck onto
- Style -> Stalk that supports stigma
- Ovary -> Where fertilisation occurs and seeds are formed within it.
26
How does reproduction occur in non-flowering plants?
Female cone:
- Grows in upper branches -> Ovule in each scale can be fertilised by wind-blown pollen
Male cone:
- Grow in lower branches -> Release pollen
27
What is a gametophyte?
- A haploid (1n) plant structure
- Produces haploid gamete that fuse to form a diploid zygote (by sexual reproduction)
28
What is a sporophyte?
- A diploid (2n) plant structure
- Can produce haploid spores by meiosis -> Spores disperse and grow by mitosis into the gametophyte
29
What are the features of fertilisation?
- Release egg from ovary (ovulation)
- Egg travels through fallopian tube (oviduct)
- Male releases semen (containing sperm) during sex
- Zygote forms strong outer membrane to stop more sperm entering
30
What is implantation?
Attachment of fertilised egg to uterine lining
31
What is the uterus?
Where pregnancy takes place
32
What is the amniotic sac?
Bag containing fluid which helps keep embryo at optimal temperature and provides cushioning
33
What is the placenta?
Provides nutrients and remove wastes
34
What is the umbilical cord?
Connects offspring to placenta
35
What are hormones?
Chemical messengers produced by body which travel in blood to other cells where they have a specific effect
36
What is oestrogen?
A hormone produced by either a mature follicle or the corpus luteum.
37
What is the role of oestrogen?
- Stimulates progesterone -> Cause endometrium (uterine lining) to thicken
- Aids blood flow to offspring
- Aids organ development
38
What is progesterone?
A hormone produced in women by the corpus luteum
39
What is the role of progesterone?
- Stimulate thickening of uterus lining
- Aids placenta function and relaxes uterus
- Helps mother’s immune system tolerate infant
- Maintains embryo in first 12 weeks of pregnancy
40
What is the follicular phase?
First half of the ovarian cycle when one follicle matures. Oestrogen levels rise
41
What is the luteal phase?
Second half of the ovarian cycle when the corpus luteum produces oestrogen and progesterone
42
What is relaxin?
A hormone that loosens uterine muscles during pregnancy
43
What is oxytocin?
A hormone that:
- Stimulates production of milk
- Trigger uterine contractions
- Trigger and maintain labour
44
What is spermatogenesis?
Sperm production by meiotic division of spermatogonia in the seminiferous tubules of the testes.
45
What oocurs in spermatogenesis?
- Occur throughout an adult male’s life
- Production occurs in response to the steroid hormone testosterone
- The epididymis is where the sperm matures and develop motility
46
What is oogenesis?
The process in which mature ova are produced in the ovary
47
What occurs during oogenesis?
- Females are born with their full complement of eggs
- Initially begins in embryo but is suspended during phosphatase of meiosis I until puberty
- At puberty, meiosis resume development but is suspended again in metaphase of meiosis II
- Meiosis II only completed when egg is fertilised
48
What is menstruation?
The process in which the endometrium (uterus lining) disintegrates, resulting in menstrual bleeding out of the vagina
49
What occurs during menstruation?
- FSH hormone stimulate development of ovarian follicles -> Release oestrogen
- Oestrogen levels increase -> Stimulate surge in LH hormone which triggers ovulation
50
What happens when fertilisation DOES NOT occur during menstruation?
Corpus luteum breaks down, progesterone secretion declines and uterine lining sheds
51
What happens when fertilisation DOES occur during menstruation?
High progesterone levels maintain thickening uterine lining
