Lecture 18: Animal Reproduction

Question 1

Describe mitosis, what are the steps?

Answer 1

cell division where each cell produces two identical daughter cells and each daughter cell has the same number of chromosomes as the parent cell

1. 1 copy of DNA per chromosome
2. replication: 2 copies of DNA per chromosome
3. cell division: chromosomes split = 1 copy of DNA per chromosome and 1 chromosome per daughter cell
4. product: 2 identical daughter cells

Question 2

Describe meiosis - include steps

Answer 2

cell division where each cell produces FOUR unique daughter cells that each have HALF the number of chromosomes as the parent cell

1. 1 copy of DNA per chromosomes
2. Replication: 2 copies DNA per chromosomes
3. cell division 1: homologous pairs split
4. cell division 2: replicated chromosomes split
5. products: 4 genetically unique daughter cells with half the chromosomes of parent cell

Question 3

Describe haploid cells. Which cells are these?

Answer 3

1 copy of each chromosome per cell (n)

reproductive cells aka GAMETES (egg and sperm)

Question 4

Describe diploid cells, which cells are these?

Answer 4

2 copies of each chromosome per cell (2n)

somatic cells aka body cells that aren’t reproductive cells

Question 5

Describe a typical sexual life cycle in animals - identify the main stages and processes

Answer 5

Diploid stage –> meiosis –> haploid stage –> fertilization –> diploid stage

1. females produce non-motile haploid (gametes) eggs by the process of MEIOSIS
2. Males produce swimming haploid (gametes) sperm by the process of MEIOSIS
3. Haploid gametes fuse by FERTILIZATION to form a diploid zygote
4. diploid zygote divides by MITOSIS to produce a new multicellular individual

Question 6

T or F: mitosis produces two identical daughter cells with the same number of chromosomes as the parent cell therefore, the daughter cells are genetic clones

Answer 6

true

Question 7

Describe and give examples of budding. State which kind of reproduction this is & give an example of animals

Answer 7

a form of asexual reproduction that occurs when new individuals grow as offshoots (buds) from the parent’s body and detach when they are self-sufficient

ex. cnidaria, porifera, and platyhelminthes
- hydra

Question 8

Describe and give examples of fragmentation. State which kind of reproduction this is & give an example of animals

Answer 8

a form of asexual reproduction where one individual breaks into two or more parts and each part grows into a new individual

ex. some echinodermata, porifera, cnidaria, and annelida
- specific: coral

Question 9

Describe and give examples of parthenogenesis. State which kind of reproduction this is & give an example of animals

Answer 9

a form of asexual reproduction that produces a diploid offspring from eggs that are not fertilized by sperm

ex. insects like aphids
some reptiles like anaconda
fish - sharks

Question 10

Advantages and disadvantages of sexual reproduction

Answer 10

Advantages:

disadvantages:

• complications finding a mate (time, energy)
• energetically costly - courtship and competition
• dangerous - risk of disease, predation, and injury

Question 11

Advantages and disadvantages of asexual reproduction

Answer 11

advantages:

• the parent passes on 100% of its genetic material (offspring = genetically identical clones)
• reproduction can occur sooner, more frequently, and with lower costs & complications

disadvantages:
- diversity is limited –> makes populations vulnerable to disease
- inability to adapt

Question 12

define gonochoristic animals and give examples

Answer 12

sexual organisms that have one sexual organ on one individual
ex. humans

Question 13

define hermaphroditic animals and give examples

Answer 13

both sexual organs on a single individual - can be simultaneous or sequential

Question 14

describe the two kinds of hermaphroditic animals and provide examples

Answer 14

1. simultaneous hermaphrodites: have both female and male reproductive structures (ex. earthworms)
2. sequential hermaphrodites change sex during their lifetime (ex. parrot fish)

Question 15

describe external fertilization

Answer 15

female releases eggs into the aquatic or moist terrestrial habitat and males release sperm onto them

Question 16

describe internal fertilization

Answer 16

sperm deposited inside female reproductive tract and egg is fertilized inside female’s body

Question 17

describe and give examples of oviparous

Answer 17

species in which offspring develop in eggs (outside of their mother)

• nourished by egg yolk and hatch externally

Question 18

describe and give examples of viviparous

Answer 18

species in which offspring develop inside of their mother, not within an egg

• nourished by placenta and live birth

Question 19

describe and give examples of ovoviviparous

Answer 19

species in which offspring develop inside of an egg inside of their mother until they are ready to hatch

• nourished by yolk and live birth

Question 20

T or F: meiosis only occurs in the reproductive organs of sexually reproducing animals? why/why not?

Answer 20

TRUE because meiosis produces haploid cells/gametes which are the reproductive cells in animals

Question 21

Which cell division process would a diploid cell use to produce haploid cells?

Answer 21

MEIOSIS

Question 22

Which cell division process would a diploid cell use to produce haploid cells?

Answer 22

MEIOSIS

Question 23

Haploid cells undergo which process to produce new diploid cells?

Answer 23

FERTILIZATION

Question 24

Define fertilization

Answer 24

the process in a sexual lifecycle that occurs when the male gamete (sperm) fuses with the female gamete (egg) to produce a diploid zygote

Question 25

Are zygotes diploid or haploid? why?

Answer 25

Diploid because they are the product of two haploid cells fusing and the product of the process fertilization

Question 26

Are zygotes diploid or haploid? why?

Answer 26

Diploid because they are the product of two haploid cells fusing and the product of the process fertilization

Question 27

Describe sexual reproduction

Answer 27

occurs through internal fertilization to produce a genetically unique individual the individual is genetically unique because half the chromosomes come from the mom and half from the dad

Question 28

What cell division process is involved in budding and fragmentation?

Answer 28

MITOSIS because it produces genetically identical clones

Question 29

T or F: many species that mostly use asexual reproduction will have sex and produce genetically unique offspring at some stage in their life cycle

Answer 29

True. example aphids reproduce by parthenogenesis all summer, but reproduce sexually in the fall when environmental conditions start changing

Question 30

Define broadcast fertilization and provide an example

Answer 30

release masses of eggs and sperm into the water sos the sperm swim to eggs ex. sea urchins

Question 31

what is a major advantage of internal fertilization over external fertilization?

Answer 31

There is a higher chance of successful reproduction when its directly inside the female

Question 32

T or F: all three types of offspring development are represented by species of fish in the group referred to as sharks

Answer 32

True

Question 33

T or F: all three types of offspring development are represented by species of fish in the group referred to as sharks

Answer 33

True

Question 34

Which of the offspring development types can be associated with external fertilization?

Answer 34

oviparity if embryos develop inside mothers body, then fertilization must be internal