1)Differentiate between continuous and discontinuous growth.
2)Describe epigeal and hypogeal Germination.
3)Give 5 adaptations of the following plants to their environment;
a)Hydrophytes
b)Xerophytes
4)Name 2 diseases caused by parasitic worms and for each mention the;
a)Causative agent
b)Mode of transmission
c)life cycle of parasite
d)Effects of the parasite on the host.
e)Adaptive characteristics of the parasite.
5)What are the 4 assumptions made when using captured recapture method for population estimation.
1) Continuous growth refers to a type of growth where there is a gradual and steady increase over time without any distinct stages or interruptions. It can be observed in organisms that continually grow and develop throughout their lifespan, such as humans. Discontinuous growth, on the other hand, refers to a type of growth where there are distinct stages or periods of growth interspersed with periods of little to no growth. This can be observed in organisms that undergo periodic growth spurts, such as insects.
2) Epigeal germination refers to the type of germination in which the cotyledons (embryonic leaves) of a seed emerge above the soil surface. This type of germination is common in dicotyledonous plants. Hypogeal germination, on the other hand, refers to the type of germination in which the cotyledons remain below the soil surface. This type of germination is common in monocotyledonous plants.
3)
a) Hydrophytes are plants that are adapted to live in aquatic environments. Some adaptations of hydrophytes include:
- Reduced or absent waxy cuticle to enhance gas exchange in water
- Floating leaves or air-filled stems for buoyancy
- Reduced root systems or roots specialized for anchoring rather than absorption
- Specialized tissues for storing gases for respiration
- Ability to perform photosynthesis in low light conditions
b) Xerophytes are plants that are adapted to live in arid or dry environments. Some adaptations of xerophytes include:
- Thick waxy cuticle to reduce water loss through evaporation
- Reduced leaf surface area or modified leaves (e.g. needle-like leaves) to minimize transpiration
- Extensive root systems to maximize water absorption
- Ability to enter dormancy during periods of drought
- CAM or C4 photosynthesis to optimize carbon fixation while minimizing water loss.
4)
a) Schistosomiasis (also known as bilharzia):
- Causative agent: Parasitic trematode worms of the genus Schistosoma
- Mode of transmission: Contact with contaminated freshwater bodies, often through swimming or wading
- Life cycle of parasite: Eggs are released in the feces or urine of infected humans and contaminate freshwater bodies where they hatch and infect the intermediate host, snails. The larval form (cercariae) are released from the snails and penetrate the skin of humans, developing into adult worms within blood vessels.
- Effects of the parasite on the host: The adult worms can cause chronic inflammation and damage to various organs, depending on the species. Symptoms can include abdominal pain, diarrhea, blood in urine, and liver damage.
- Adaptive characteristics of the parasite: The parasite has a complex life cycle that involves multiple hosts, which allows it to survive and reproduce in different environments.
b) Ascariasis:
- Causative agent: Parasitic roundworms of the genus Ascaris
- Mode of transmission: Ingestion of food or water contaminated with Ascaris eggs
- Life cycle of parasite: Eggs ingested by humans hatch in the intestines, and the larvae migrate through the bloodstream to the lungs. From the lungs, they are coughed up and swallowed, returning to the intestines to mature into adult worms.
- Effects of the parasite on the host: Heavy infestations can cause abdominal pain, diarrhea, and malnutrition. In severe cases, the worms can cause intestinal blockage or migrate to other organs, potentially leading to more serious complications.
- Adaptive characteristics of the parasite: The parasite produces a large number of eggs that are passed in human feces, increasing the chances of transmission. The eggs are resistant to environmental conditions and can survive for long periods outside the host.
5) The assumptions made when using the capture-recapture method for population estimation are:
a) The population is closed: There should be no immigration, emigration, birth, or death within the population during the study period.
b) Marked individuals are randomly distributed: The marked individuals must mix randomly with the rest of the population and have the same probability of being captured as unmarked individuals.
c) Marks do not affect the success of capture or survival: The marking method should not affect the probability of capturing or recapturing individuals, and marks do not affect the survival or behavior of the individuals.
d) The population has not changed between capture events: The population size remains relatively stable between capture events, and there are no significant changes in the population size due to factors such as births, deaths, immigration, or emigration.
Note: The assumptions may vary depending on the specific application and study design.
1) Continuous growth refers to a pattern of growth where there is a consistent increase in size or number over time without any noticeable breaks or periods of stasis. This type of growth can be seen in organisms like plants, which continuously add new cells and tissues throughout their lifespan.
Discontinuous growth, on the other hand, is characterized by periods of rapid growth followed by periods of little to no growth. This type of growth can be seen in organisms like humans, where there is a period of rapid growth during childhood and adolescence, followed by a period of slower growth during adulthood.
2) Epigeal germination is a type of seed germination where the cotyledons (seed leaves) emerge above the soil surface. This is commonly seen in dicot plants. The cotyledons become photosynthetic and perform the function of leaves.
Hypogeal germination, on the other hand, is a type of seed germination where the cotyledons remain below the soil surface. The shoot emerges from the soil, while the cotyledons stay within the seed. This is commonly seen in monocot plants.
3) a) Hydrophytes are plants that are adapted to growth in aquatic or waterlogged environments. Some adaptations of hydrophytes include:
- Presence of air spaces in their stems and leaves to provide buoyancy.
- Reduced or no cuticle on the leaves to facilitate gas exchange.
- Extensive root systems to anchor the plants in waterlogged soils.
- Thin, flexible stems to avoid breaking in water currents.
- Floating leaves or submerged leaves with specialized structures to optimize gas exchange.
b) Xerophytes are plants that are adapted to growth in dry or arid environments. Some adaptations of xerophytes include:
- Thick, waxy cuticle on leaves to reduce water loss via transpiration.
- Reduced leaf surface area to lower water loss.
- Hairs or spines on leaves to trap moisture from the air.
- Extensive root systems to access water deep within the soil.
- Succulent stems or leaves to store water.
4) Two diseases caused by parasitic worms are:
a) Schistosomiasis:
- Causative agent: Schistosoma spp. (a type of trematode worm)
- Mode of transmission: Contact with water contaminated with parasite-infected snails.
- Life cycle of parasite: The parasite undergoes a complex life cycle involving freshwater snails as intermediate hosts. The primary infection occurs when humans come into contact with contaminated water.
- Effects on the host: Schistosomiasis can cause a range of symptoms, including fever, abdominal pain, bloody urine or stool, liver enlargement, and in severe cases, it can lead to organ damage and death.
- Adaptive characteristics of the parasite: The parasite has evolved to infect snails as intermediate hosts, allowing it to continue its life cycle and infect humans.
b) Ascariasis:
- Causative agent: Ascaris lumbricoides (a type of roundworm)
- Mode of transmission: Ingestion of food or water contaminated with feces containing parasite eggs.
- Life cycle of parasite: The eggs are ingested, and once inside the human host, they hatch in the intestines. The larvae then migrate through various organs before returning to the intestines to mature into adult worms.
- Effects on the host: Ascariasis can cause abdominal pain, diarrhea, vomiting, malnutrition, and in severe cases, intestinal blockage.
- Adaptive characteristics of the parasite: The parasite produces a large number of eggs to ensure its survival and transmission, and it can withstand harsh environments outside the host, allowing it to persist in contaminated soil.
5) When using the capture-recapture method for population estimation, the following assumptions are made:
- Marked individuals have an equal chance of being recaptured as unmarked individuals.
- Marked individuals do not lose their marks or acquire new marks between initial capture and recapture.
- The population is closed or well-mixed, meaning there are no births, deaths, immigration, or emigration during the period of study.
- The sampling process does not significantly harm or alter the behavior of the individuals being studied.