chapter 9 - reproduction Flashcards

unit 2 aos 2

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1
Q

genetic diversity of a population

A

the amount of genetic variation

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2
Q

gene pool

A

the sum of all the different genes and alleles that are present in a population and species
-influenced and maintained by a number of naturally occurring mechanisms

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3
Q

why is genetic diversity important?

A

-protects longevity of species by guarding against disadvantageous environmental changes
-larger the gene pool, greater the resilience to environmental change
-populations with more alleles are more likely to have alleles that are already adapted to new environment

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4
Q

sexual reproduction

A

-involves fusion of two haploid gametes to form a single, genetically unique, diploid zygote

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5
Q

oviparity

A

-eggs are released into the external environment, where the embryo develops
-occurs in frogs, snakes, lizards, hens, ducks etc

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6
Q

viviparity

A

-embryo develops inside mother’s body and is born after a period of gestation
-occurs in humans, bears, giraffes, cattle, salamanders etc

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7
Q

reproduction of angiosperms (pollination)

A

-pollen is collected by stigma of flower and fuses with ovule
-embryo that develops will become a seed
-occurs in plants

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8
Q

advantages of sexual reproduction

A

-increases genetic diversity by allowing for recombinant offspring
-improving genetic resistance by promoting presence of different alleles
-combining genetic material reduces chances of offspring inheriting genetic disorder

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9
Q

disadvantages of sexual reproduction

A

-cost of male progeny
-time, energy, and resources required to attract and find a mate
-risk of stds
-risk of losing offspring to outside influences

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10
Q

asexual reproduction

A

-offspring/daughter cells are clones of each other and of parent

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11
Q

types of asexual reproduction

A

-binary fission
-budding
-fragmentation
-vegetative propagation
-sporogenesis
-parthenogenesis

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12
Q

binary fission

A

-one organism divides into two identical organisms
-occurs in simple prokaryotic organisms

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13
Q

budding

A

-involves formation of a bud, which forms due to increased cell growth, then breaks away from main organism, where it can develop into separate organism
-occurs in yeast, sponges, jellyfish, coral, worms

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14
Q

fragmentation

A

-involves parent organism breaking into separate fragments, each of which is capable into developing in separate organism
-occurs in simple eukaryotes (worms? and starfish) and many plant species

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15
Q

vegetative propagation

A

-allows a plant to reproduce without seeds
-part of plant breaks away from original plant, then independently grows into new plant

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16
Q

sporogenesis

A

-involves formation of spores (found on surface on organisms), which are dispersed into the surroundings where they grow into larger organisms
-occurs in many plants, fungi, algae, moulds

17
Q

parthenogenesis

A

-an embryo can develop from a female gamete alone
-results in eggs produced via mitosis and develop into organism identical to female parent
-rare and occurs in less than 0.1% of all vertebrate species

18
Q

advantages of asexual reproduction

A

-populations grow faster than sexually reproducing ones
-offspring identical to parent - important as organism’s phenotype is fine-tuned to survive environment
-doesn’t require mate
-requires little parental investment

19
Q

disadvantages of asexual reproduction

A

-genetic diversity is low, populations may suffer from rapid environmental change

20
Q

reproductive cloning in animals

A

-somatic cell transfer
-embryo splitting

21
Q

somatic cell transfer (scnt)

A

-involves donated egg cells and donated somatic cell
-offspring is genetically identical to donated somatic cell

22
Q

steps of scnt

A
  1. enucleation - removal/destruction of nucleus from donated egg cell to produce an enucleated egg cell
  2. extraction - donated somatic cell’s nucleus is extracted
  3. insertion - somatic cell’s nucleus is inserted into enucleated egg cell
  4. development - cell begins to divide and develop into an embryo, which is implanted into a surrogate mother
23
Q

applications of scnt

A

-has been used to clone living and recently deceased animals
-dolly the sheep in 1997

24
Q

complications of scnt

A

-animal suffering
-human cloning - illegal in many countries
-premature aging

25
Q

embryo splitting

A

-embryos are split artificially for agricultural applications
-embryos are implanted into surrogate mothers where embryo development is completed - clone is genetically identical to original embryo
-ideal splitting is between 6-8 cells

26
Q

applications of embryo splitting

A

-in agriculture, is conducted with ivf to fertilise offspring with desirable traits

27
Q

complications of embryo splitting

A

-alteration of embryos
-decreased genetic diversity
-research animals

28
Q

reproductive cloning in plants

A

-plant tissue culturing
-plant cutting
-plant grafting

29
Q

plant tissue culturing (micropropagation)

A

-plant cells are grown on a nutrient culture medium, aspects of environment are controlled (lab)
-as it develops a callus begins to form
-callus then can be separated into several cultures and stimulated to grow into clones of original plant

30
Q

applications of plant tissue culturing

A

-produce plants all year round in disease-free environment
-clones for agricultural research, clone rare plants

31
Q

plant cuttings

A

-obtained by cutting off fragment of plant
-fragment is placed in soil/water and will grow under right conditions, producing clone of original plant

32
Q

plant grafting

A

-involves attaching stem of one plant (scion) to stem of another plant with an already developed root system (rootstock)
-eventually, these 2 sections will grow and fuse together, producing clone of plant that scion was taking

33
Q

applications of cutting and grafting

A

-relatively old cloning techniques
-allow for rapid growth of desired plant, however grafting often helps provide plants with cold tolerance, resistance to disease, and increased productivity

34
Q

biological implications of plant cloning

A

-unrestrained cloning could lead to reduction in genetic diversity
-cloned population is more susceptible to disease, pests, and environmental changes