IPA kelas 9 Bab 1 kurikulum merdeka semester 1 pertumbuhan dan perkembangan

Summary

This video provides an in-depth overview of growth and development in both humans and animals, focusing on stages from infancy to adulthood. It explains the differences between growth and development, highlighting physical and cognitive changes throughout life. The video also covers reproductive systems and embryonic development, explaining oviparous, ovoviviparous, and viviparous reproduction. In addition, it details metamorphosis in animals, plant growth phases, and key factors influencing growth and development, such as genetics, hormones, and environmental factors. This educational summary is aimed at 9th-grade students studying science based on the independent curriculum.

Takeaways

• 😀 Growth is a measurable process (e.g., height and weight), while development refers to the increase in abilities over time, such as language skills.
• 😀 The human life cycle begins with a baby, progresses to childhood, adolescence, adulthood, and ends in the aging process.
• 😀 Human growth and development start at conception, with the zygote undergoing mitosis to form a fetus.
• 😀 Babies grow rapidly in their first 1 to 2 years, gaining weight and developing motor skills like rolling over, crawling, walking, and speaking.
• 😀 The childhood phase, starting at age 2, is characterized by increased curiosity, language development, and coordination.
• 😀 Adolescence, which starts from age 9 to 15, marks the onset of puberty, with changes like menstruation in females and sperm production in males.
• 😀 Adulthood begins after adolescence, with secondary sexual characteristics stabilizing and aging signs like gray hair and reduced muscle mass occurring around 30.
• 😀 In animals, growth and development can differ: oviparous animals lay eggs, ovoviviparous animals develop embryos inside eggs until they hatch, and viviparous animals develop embryos inside the mother's body.
• 😀 Metamorphosis is observed in some animals, where the young phase looks different from the adult phase, such as in amphibians, insects, and certain crustaceans.
• 😀 Plants grow and develop through primary growth (vertical growth from apical meristems) and secondary growth (wider growth from lateral meristems).
• 😀 Factors influencing growth and development in plants include internal factors like genetics and hormones, and external factors like sunlight, water, soil, and temperature.

Q & A

What is the difference between growth and development in humans?

Growth refers to measurable changes like height and weight, while development is the progression of abilities, such as a baby learning to speak over time.

What are the main stages of the human life cycle?

The human life cycle includes the baby stage, childhood, adolescence (puberty), adulthood, and old age. Each stage is marked by distinct physical and emotional changes.

What are the key developments in a baby during the first two years?

During the first two years, babies experience rapid physical growth, with significant increases in weight and the development of motor skills like rolling over, crawling, walking, and speaking.

At what age does puberty typically begin, and what are the key hormones involved?

Puberty typically begins between the ages of 9 and 15. In women, hormones like estrogen and progesterone trigger sexual development, while in men, testosterone plays a key role in the development of secondary sexual characteristics.

What physical changes occur during adulthood?

In adulthood, growth stops, and signs of aging begin to appear, such as gray hair, reduced muscle mass, and, for women, the cessation of menstruation (menopause).

How does sexual reproduction in animals differ across species?

In animals, sexual reproduction involves the meeting of egg and sperm. Some species are oviparous (egg-laying), others are ovoviviparous (developing embryos inside eggs within the mother), and some are viviparous (giving birth to live young).

What is the function of the amniotic egg in oviparous animals?

The amniotic egg protects and nourishes the developing embryo. It has a shell for protection, albumin for gas exchange, yolk for food supply, amniotic fluid for cushioning, and allantois for waste storage.

What is the key difference between complete and incomplete metamorphosis in insects?

In complete metamorphosis, insects undergo four distinct stages: egg, larva, pupa, and adult. In incomplete metamorphosis, insects only go through three stages: egg, nymph (which resembles the adult), and adult.

What are the stages of metamorphosis in amphibians?

Amphibians undergo a perfect metamorphosis with stages including egg, tadpole, tadpole with tail, legged perch, young frog, and adult frog.

How do plants grow from seeds?

Plants start from seeds, which contain an embryo. Once the seed is in favorable conditions, it germinates. The embryo grows using food reserves in the cotyledons and begins developing roots, stems, and leaves.

What are the two types of growth in plants?

Plants exhibit primary growth (increase in height) through apical meristems, and secondary growth (increase in diameter) through lateral meristems.

What factors influence the growth and development of plants?

Growth and development in plants are influenced by both internal factors, like genetics and hormones (e.g., auxins, gibberellins), and external factors such as sunlight, water, temperature, and soil conditions.