Growth, Development and Reproduction | Jamb(UTME) Agriculture

Growth, Development, and Reproduction

1. Growth refers to the increase in size and mass of an organism.
2. Development involves the progression from a simple to a more complex state.
3. Reproduction is the biological process by which new organisms are produced.
4. Sexual reproduction involves the combination of gametes from two parents.
5. Asexual reproduction involves a single organism producing offspring without the involvement of gametes.
6. Growth is influenced by environmental factors like temperature, light, and nutrients.
7. Development is often guided by genetic instructions encoded in DNA.
8. Reproductive cycles are regulated by hormonal signals in animals and plants.
9. The cell cycle is critical for growth and development, including mitosis and meiosis.
10. In plants, growth occurs in meristems, regions of active cell division.
11. In animals, growth often involves an increase in cell number and size.
12. The differentiation process results in specialized cells, tissues, and organs.
13. The development of an organism follows a pattern known as ontogeny.
14. Growth involves both internal (genetic) and external (environmental) factors.
15. Morphogenesis is the process by which cells, tissues, and organs take shape.
16. In plants, the growth pattern can be affected by the availability of water and light.
17. Plant hormones like auxins and gibberellins control growth and development.
18. Animals also exhibit growth patterns that follow their genetic programming.
19. The stages of growth and development include embryonic, juvenile, adult, and senescence stages.
20. Reproductive organs in both plants and animals mature through a process called maturation.
21. In sexual reproduction, meiosis produces gametes that carry half the genetic information.
22. The formation of gametes involves both genetic recombination and cell division.
23. In asexual reproduction, offspring are genetically identical to the parent.
24. Organisms exhibit a range of reproductive strategies, from live birth to egg-laying.
25. Some organisms can switch between sexual and asexual reproduction depending on environmental conditions.
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Gametogenesis

26. Gametogenesis is the process by which gametes (sperm and eggs) are produced.
27. In males, spermatogenesis occurs in the testes, producing sperm cells.
28. In females, oogenesis takes place in the ovaries, producing egg cells.
29. Both spermatogenesis and oogenesis involve meiosis to reduce chromosome number.
30. Spermatogenesis begins with a diploid spermatogonium undergoing mitosis.
31. Oogenesis begins with a diploid oogonium, which undergoes meiosis to form eggs.
32. The process of spermatogenesis produces four functional sperm from one precursor cell.
33. Oogenesis produces one functional egg and three non-functional polar bodies.
34. Meiosis I in oogenesis is completed only after fertilization in some species.
35. Spermatogenesis results in the continuous production of sperm throughout the male's life.
36. In females, oogenesis is a cyclical process that occurs in monthly intervals.
37. The formation of sperm involves cellular differentiation, including the development of a flagellum.
38. The egg cell is larger than the sperm and contains the nutrients required for early development.
39. Sperm cells are motile, while eggs are immobile, relying on sperm for movement.
40. The genetic diversity of gametes is due to processes such as crossing over and independent assortment during meiosis.
41. The maturation of gametes is regulated by hormones like FSH and LH in both males and females.
42. Spermatogenesis involves the formation of a haploid nucleus and a tail for movement.
43. Oogenesis involves unequal cytokinesis, resulting in a large egg and smaller polar bodies.
44. Spermatogenesis results in the formation of sperm capable of fertilizing the egg.
45. The process of gametogenesis is essential for maintaining genetic diversity in sexually reproducing populations.
46. In humans, spermatogenesis starts at puberty and continues throughout life.
47. In females, oogenesis begins during fetal development and pauses at birth, resuming at puberty.
48. Both male and female gametogenesis are regulated by the hypothalamic-pituitary-gonadal axis.
49. Environmental factors like temperature and toxins can influence gametogenesis.
50. Certain genetic mutations can affect gametogenesis, leading to infertility.
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Pollination

51. Pollination is the transfer of pollen from the male to the female part of a flower.
52. It is essential for the fertilization of most flowering plants.
53. Pollination can occur via biotic agents like bees, butterflies, and birds.
54. Abiotic pollination involves non-living factors like wind and water.
55. Cross-pollination occurs when pollen is transferred between flowers of different plants.
56. Self-pollination occurs when pollen is transferred within the same flower or plant.
57. Pollinators are attracted to flowers by color, scent, and nectar.
58. Some plants have mechanisms that prevent self-pollination to encourage genetic diversity.
59. The stigma of the female flower is the receptor for pollen during pollination.
60. Insects, especially bees, play a critical role in the pollination of many crops.
61. Wind-pollinated plants often produce large quantities of pollen to increase the likelihood of pollination.
62. Pollination is the first step toward fertilization in flowering plants.
63. In some plants, pollination is facilitated by the use of specialized structures like anthers or stigmas.
64. Flowers that are pollinated by birds tend to be brightly colored and produce copious amounts of nectar.
65. Pollination can occur both within the same plant or between different plants, increasing genetic diversity.
66. Pollinators may inadvertently transfer pollen from one flower to another while foraging for food.
67. The pollen tube grows after successful pollination to reach the ovule for fertilization.
68. Pollination may require specific environmental conditions, such as the presence of specific pollinators or weather patterns.
69. Some plants have developed unique pollination strategies to attract specific pollinators, such as orchids mimicking the appearance of female insects.
70. The timing of pollination can be crucial, with some flowers opening only at specific times of the day to attract certain pollinators.
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Fertilization

71. Fertilization is the process where male and female gametes fuse to form a zygote.
72. In animals, fertilization can occur either internally or externally.
73. External fertilization happens in water, where gametes meet outside the body.
74. Internal fertilization takes place inside the female’s reproductive tract.
75. During fertilization, the sperm cell fuses with the egg cell to form a diploid zygote.
76. The sperm penetrates the egg through the zona pellucida, a protective layer around the egg.
77. Fertilization activates the egg, triggering the beginning of embryonic development.
78. The fusion of sperm and egg restores the diploid number of chromosomes in the zygote.
79. Fertilization is followed by a series of divisions called cleavage, where the zygote divides into many smaller cells.
80. The cortical reaction prevents polyspermy, ensuring only one sperm fertilizes the egg.
81. Sperm motility is essential for the fertilization process, allowing sperm to travel toward the egg.
82. The egg’s cytoplasm contains molecules that contribute to the development of the embryo post-fertilization.
83. In some species, fertilization is facilitated by sperm competition, where multiple sperm compete to fertilize the egg.
84. Fertilization is a critical process for sexual reproduction, ensuring genetic diversity.
85. Successful fertilization results in the formation of a zygote, which undergoes further development.
86. In plants, fertilization occurs after successful pollination, with the pollen grain germinating to form the pollen tube.
87. Fertilization in plants involves the fusion of male and female gametes within the ovule.
88. After fertilization, the fertilized ovule develops into a seed.
89. In plants, fertilization is sometimes followed by double fertilization, where one sperm fertilizes the egg and another sperm fuses with two polar nuclei.
90. The resulting endosperm in plants provides nutrients for the developing embryo.
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Embryo Formation and Development

91. Embryo formation begins immediately after fertilization with the zygote undergoing cleavage.
92. In animals, the embryo develops from the blastula stage to the gastrula stage.
93. The gastrula forms three germ layers: ectoderm, mesoderm, and endoderm, which give rise to all tissues and organs.
94. In plants, embryo development occurs inside the seed after fertilization.
95. The embryo’s development is regulated by gene expression and signaling molecules.
96. In humans, the embryonic stage lasts from fertilization to the eighth week of development.
97. The development of an embryo involves differentiation, where cells become specialized for specific functions.
98. In plants, the embryo develops into the mature plant structure after germination.
99. The protection and nourishment of the embryo are critical for successful development, provided by the placenta in mammals or endosperm in plants.
100. The successful development of an embryo leads to the formation of a new organism capable of independent life.

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