(a) Explain briefly the following types of fertilization in animals; (i) external fertilization (ii) internal fertilization
(b) Name two groups of animal each that exhibit the types of fertilization in (a)
(c)(i) If the placenta in a pregnant woman is detached from the uterine wall, give three effect this will have on the foetus
(ii) Name three other features in the uterus of a pregnant woman that are useful for the development of the foetus
(d) Explain briefly how the activities of organisms bring bout dynamic equilibrium in the habitat.
(e) State four problems that organisms in the intertidal zone of a marine habitat could encounter.
(f) Explain briefly the reasons that the following factors are necessary for germination; (i) moisture (ii) viable seeds
(g) Explain briefly the reason light energy is considered a limiting factor in the production of foods by autotrophs.
(a)
(i) External fertilization is the type of fertilization where the eggs are fertilized by sperm outside the female's body. This is common in aquatic animals like fish, amphibians, and some invertebrates.
(ii) Internal fertilization is the type of fertilization where the sperm fertilizes the eggs inside the female's body. This is common in mammals, reptiles, birds, and some insects.
(b)
Two groups of animals that exhibit external fertilization are fish and amphibians. Two groups of animals that exhibit internal fertilization are mammals and reptiles.
(c)
(i) If the placenta detaches from the uterine wall, this can have three effects on the fetus:
- Reduced oxygen and nutrient supply to the fetus, which can lead to growth restriction and developmental problems.
- Increased risk of bleeding for the mother, which can be life-threatening.
- Increased risk of premature birth, as the detachment of the placenta can trigger labor.
(ii) Three other features in the uterus of a pregnant woman that are useful for the development of the fetus include:
- The amniotic fluid, which provides a protective environment for the fetus and helps regulate temperature.
- The umbilical cord, which provides the fetus with oxygen and nutrients from the mother.
- The uterus itself, which expands to accommodate the growing fetus and helps protect it from physical trauma.
(d)
Dynamic equilibrium in a habitat refers to a state of balance between the living and non-living elements of an ecosystem. Organisms play a crucial role in maintaining this balance by carrying out activities such as photosynthesis, respiration, predation, and decomposition. These activities help regulate the levels of carbon dioxide, oxygen, and other important substances in the environment.
(e)
Four problems that organisms in the intertidal zone of a marine habitat could encounter are:
- Exposure to changes in temperature and salinity as the tides come in and go out.
- Exposure to extreme conditions such as drying out at low tide and being underwater at high tide.
- Competition for limited resources such as food and space.
- Threats from predators such as birds and sea stars.
(f)
(i) Moisture is necessary for germination because seeds need water to begin the process of germination. Water activates the enzymes in the seed and starts the metabolic processes that lead to growth.
(ii) Viable seeds are necessary for germination because only seeds that are capable of growing into a plant will germinate. Seeds that are not viable, for example due to disease or damage, will not germinate.
(g)
Light energy is considered a limiting factor in the production of food by autotrophs because it is an essential component of photosynthesis. Autotrophs, like plants
(a)
(i) External fertilization is the type of fertilization where the eggs are fertilized by sperm outside the female's body. This is common in aquatic animals like fish, amphibians, and some invertebrates.
(ii) Internal fertilization is the type of fertilization where the sperm fertilizes the eggs inside the female's body. This is common in mammals, reptiles, birds, and some insects.
(b)
Two groups of animals that exhibit external fertilization are fish and amphibians. Two groups of animals that exhibit internal fertilization are mammals and reptiles.
(c)
(i) If the placenta detaches from the uterine wall, this can have three effects on the fetus:
- Reduced oxygen and nutrient supply to the fetus, which can lead to growth restriction and developmental problems.
- Increased risk of bleeding for the mother, which can be life-threatening.
- Increased risk of premature birth, as the detachment of the placenta can trigger labor.
(ii) Three other features in the uterus of a pregnant woman that are useful for the development of the fetus include:
- The amniotic fluid, which provides a protective environment for the fetus and helps regulate temperature.
- The umbilical cord, which provides the fetus with oxygen and nutrients from the mother.
- The uterus itself, which expands to accommodate the growing fetus and helps protect it from physical trauma.
(d)
Dynamic equilibrium in a habitat refers to a state of balance between the living and non-living elements of an ecosystem. Organisms play a crucial role in maintaining this balance by carrying out activities such as photosynthesis, respiration, predation, and decomposition. These activities help regulate the levels of carbon dioxide, oxygen, and other important substances in the environment.
(e)
Four problems that organisms in the intertidal zone of a marine habitat could encounter are:
- Exposure to changes in temperature and salinity as the tides come in and go out.
- Exposure to extreme conditions such as drying out at low tide and being underwater at high tide.
- Competition for limited resources such as food and space.
- Threats from predators such as birds and sea stars.
(f)
(i) Moisture is necessary for germination because seeds need water to begin the process of germination. Water activates the enzymes in the seed and starts the metabolic processes that lead to growth.
(ii) Viable seeds are necessary for germination because only seeds that are capable of growing into a plant will germinate. Seeds that are not viable, for example due to disease or damage, will not germinate.
(g)
Light energy is considered a limiting factor in the production of food by autotrophs because it is an essential component of photosynthesis. Autotrophs, like plants