GENERAL BIOLOGY QUARTER 4

Introduction Reproduction is an essential process for the survival and continuation of life. Both plants and animals have developed unique reproductive systems to ensure the production of offspring. While there are similarities between the reproductive systems of plants and animals, there are also significant differences.

Plant Reproductive System

Plants have a diverse range of reproductive strategies, but most commonly, they reproduce through sexual reproduction. The plant reproductive system consists of the following components:

1. Flowers

• Flowers are the reproductive structures of plants.

• They contain male and female reproductive organs.

2. Male Reproductive Organs

• The male reproductive organs in plants are called stamens.

• Each stamen consists of a filament and an anther.

• The anther produces pollen grains, which contain the male gametes.

3. Female Reproductive Organs

• The female reproductive organs in plants are called pistils or carpels.

• Each pistil consists of an ovary, a style, and a stigma.

• The ovary contains ovules, which are the female gametes.

4. Pollination

• Pollination is the transfer of pollen from the anther to the stigma.

• It can occur through various means, such as wind, water, or animal pollinators.

5. Fertilization

• After pollination, the pollen grain germinates on the stigma and grows a pollen tube down the style to reach the ovary.

• The male gametes then fertilize the ovules, resulting in the formation of seeds.

6. Seed Dispersal

• Once the seeds are formed, they need to be dispersed to new locations for germination.

• This can be done through wind, water, animals, or other mechanisms.

Animal Reproductive System

Animals have diverse reproductive strategies, ranging from external fertilization to internal fertilization. The animal reproductive system consists of the following components:

1. Gonads

• The gonads in animals are the primary reproductive organs.

• In males, the gonads are the testes, which produce sperm.

• In females, the gonads are the ovaries, which produce eggs.

2. Gametes

• Animals produce specialized reproductive cells called gametes.

• In males, the gametes are sperm, while in females, the gametes are eggs.

3. Fertilization

• Fertilization in animals can occur internally or externally.

• Internal fertilization occurs when the sperm fertilizes the egg inside the female's body.

• External fertilization occurs when sperm and eggs are released into the environment, and fertilization happens outside the body.

4. Development

• After fertilization, the zygote develops into an embryo.

• The embryo undergoes further development, either inside the female's body (viviparity) or outside the female's body (oviparity).

5. Parental Care

• Some animals provide parental care to their offspring, ensuring their survival and growth.

• This can include protecting the eggs or young, providing food, or teaching them essential skills.

Key Comparisons Between Plant and Animal Reproduction

Lesson 2: Plant and Animal Reproduction Process

Plant Reproduction

Plants can reproduce both sexually and asexually.

Sexual Reproduction in Plants

1. Pollination – Transfer of pollen from the anther to the stigma.

2. Fertilization – The pollen tube delivers sperm cells to the ovule, forming an embryo.

3. Seed Formation – The fertilized ovule develops into a seed.

Asexual Reproduction in Plants

• Vegetative Propagation – New plants develop from stems, roots, or leaves.

• Budding – A small outgrowth forms a new individual.

• Fragmentation – The parent plant breaks into fragments that grow into new plants.

Animal Reproduction

Sexual Reproduction in Animals

1. Mating – Brings male and female reproductive organs together.

2. Fertilization – Sperm fuses with an egg to form a zygote.

3. Embryonic Development – The zygote divides and grows into an embryo.

4. Live Birth or Egg Laying – Mammals give birth, while reptiles, birds, and some fish lay eggs.

Asexual Reproduction in Animals

• Budding – Seen in jellyfish and corals.

• Parthenogenesis – Unfertilized eggs develop into embryos (e.g., in certain reptiles and insects).

Lesson 3: Plant and Animal Development

Plant Development

1. Seed Development – The seed contains an embryo, a food source, and a protective seed coat.

2. Germination – The embryo grows when conditions are favorable.

3. Growth – Growth occurs at root and shoot tips (meristems).

Animal Development

1. Fertilization – Sperm fuses with an egg to form a zygote.

2. Embryonic Development – The embryo develops germ layers:

   • Ectoderm – Skin, nervous system.

   • Mesoderm – Muscles, bones, circulatory system.

   • Endoderm – Digestive and respiratory systems.

3. Post-Embryonic Development – Includes metamorphosis in some species (e.g., caterpillar to butterfly).

Comparison Between Plant and Animal Development

By understanding the similarities and differences in plant and animal development, we gain a deeper appreciation for the complexity and diversity of life on Earth.

Lesson 4: Plant and Animal Digestive System and Nutrition

Both plants and animals require nutrients to survive and grow. However, their digestive systems and methods of obtaining nutrients differ significantly.

Introduction

Plants have a unique way of obtaining nutrients through photosynthesis. They use their leaves to capture sunlight and convert it into energy.

Plant Digestive System and Nutrition

1. Photosynthesis

   • Plants use chlorophyll, a pigment found in their leaves, to capture sunlight.

   • Through photosynthesis, plants convert carbon dioxide and water into glucose (a type of sugar) and oxygen.

   • Glucose is used as an energy source for the plant.

2. Roots

   • Plants have roots that absorb water and minerals from the soil.

   • Essential minerals such as nitrogen, phosphorus, and potassium support plant growth and development.

3. Stomata

   • Plants have tiny openings called stomata on their leaves.

   • Stomata allow for the exchange of gases such as carbon dioxide and oxygen with the environment.

4. Transportation

   • Plants have a vascular system that transports water, nutrients, and sugars throughout the plant.

   • Xylem vessels transport water and minerals from the roots to the leaves.

   • Phloem vessels transport sugars from the leaves to other parts of the plant.

Animal Digestive System and Nutrition

Animals have a more complex digestive system compared to plants. They consume food and break it down into smaller molecules that can be absorbed and used by their bodies.

1. Ingestion

   • Animals consume food through their mouths.

   • Different animals have different feeding habits:

     • Herbivores (plant-eaters)

     • Carnivores (meat-eaters)

     • Omnivores (eat both plants and animals)

2. Digestion

   • Animals have specialized organs for digestion, such as the stomach and intestines.

   • Food is broken down into smaller molecules through mechanical and chemical processes.

   • Enzymes play a crucial role in breaking down complex molecules into simpler ones.

3. Absorption

   • After digestion, nutrients are absorbed into the bloodstream through the walls of the small intestine.

   • The bloodstream then transports these nutrients to different parts of the body, where they are used for energy, growth, and repair.

4. Elimination

   • Waste products, such as undigested food and other indigestible materials, are eliminated from the body through the rectum and anus in the form of feces.

Comparison of the Plant and Animal Digestive Systems and Their Methods of Nutrition

Examples Illustrating the Differences Between Plant and Animal Digestive Systems and Nutrition

1. Herbivorous Animal

   • A cow is an herbivorous animal that consumes grass.

   • It has a complex digestive system with multiple stomach compartments to break down tough plant material and extract nutrients.

2. Photosynthetic Plant

   • A sunflower uses photosynthesis to convert sunlight into energy.

   • It absorbs water and minerals from the soil through its roots and transports sugars to other parts of the plant through phloem vessels.

3. Omnivorous Animal

   • A human is an omnivorous animal that consumes a variety of foods, including plants and animals.

   • The human digestive system includes organs such as the mouth, stomach, small intestine, and large intestine, which work together to digest and absorb nutrients.

Conclusion

• Plants and animals have distinct digestive systems and methods of obtaining nutrients.

• Plants use photosynthesis to convert sunlight into energy, while animals consume food and break it down through digestion.

• Understanding these differences helps us appreciate the diversity of life on Earth and how organisms adapt to their environments.

Lesson 5: Plant and Animal Respiratory System and Gas Exchange

Introduction

Respiration is the process by which organisms exchange gases with their environment. While both plants and animals have respiratory systems, there are key differences between them.

Plant Respiratory System

1. Stomata

   • Small openings on leaves, stems, and other parts.

   • Allow for gas exchange (oxygen and carbon dioxide).

2. Guard Cells

   • Specialized cells surrounding stomata.

   • Control opening and closing to regulate gas exchange and water loss.

3. Photosynthesis and Respiration

   • Photosynthesis takes in carbon dioxide and releases oxygen.

   • Respiration in plants takes in oxygen and releases carbon dioxide.

Animal Respiratory System

1. Lungs

   • Mammals, birds, and reptiles use lungs.

   • Oxygen is absorbed into the bloodstream in alveoli.

2. Other Mechanisms

   • Fish use gills.

   • Insects use tracheal systems.

3. Circulatory System Connection

   • Blood transports oxygen to cells and removes carbon dioxide.

Gas Exchange

Conclusion

• Plants use stomata for gas exchange, while animals have specialized respiratory organs.

Lesson 6: Plant and Animal Circulatory System and Transport Mechanism

Introduction

• Plants use xylem and phloem for transport.

• Animals use a heart and blood vessels.

Plant Circulatory System

1. Xylem - Transports water and minerals.

2. Phloem - Transports sugars and nutrients.

Animal Circulatory System

1. Heart - Pumps blood.

2. Blood Vessels - Carry blood (arteries, veins, capillaries).

3. Blood - Transports oxygen, nutrients, and waste.

Conclusion

• Plants rely on passive transport.

• Animals have an active circulatory system.

Lesson 7: Plant and Animal Urinary System and Fluid Regulation

Introduction

• Animals have kidneys, bladder, and urethra.

• Plants use roots, xylem, and stomata.

Animal Urinary System

1. Kidneys - Filter waste.

2. Bladder - Stores urine.

3. Urethra - Expels urine.

Plant Fluid Regulation

1. Roots - Absorb water.

2. Xylem - Transports water.

3. Stomata - Regulate water loss.

Conclusion

• Animals excrete waste through urine.

• Plants regulate fluid through transpiration.

Lesson 8: Plant and Animal Endocrine System with Chemical and Nervous Control

Both plants and animals have complex systems that regulate and control various physiological processes.

Introduction

• In animals, this control is primarily achieved through the endocrine system, which consists of glands that secrete hormones into the bloodstream.

• Plants, on the other hand, lack a circulatory system but have a similar mechanism called the plant endocrine system.

Plant Endocrine System

Hormones in Plants

• Plants produce hormones that regulate growth, development, and responses to environmental stimuli.

• These hormones act as chemical messengers, synthesized in one part of the plant and transported to target cells in another part.

Major Plant Hormones

1. Auxins – Promote cell elongation, root development, and apical dominance.

2. Gibberellins – Stimulate stem elongation, seed germination, and flowering.

3. Cytokinins – Promote cell division, delay senescence, and regulate nutrient distribution.

4. Abscisic Acid – Inhibits growth, promotes seed dormancy, and regulates stomatal closure.

5. Ethylene – Regulates fruit ripening, leaf senescence, and abscission.

Mode of Transport in Plants

• Unlike animals, plants lack a circulatory system to transport hormones. Instead, they use vascular tissues:

  • Xylem carries hormones upwards from the roots to the shoots.

  • Phloem transports hormones in both directions.

Target Cells in Plants

• Plant hormones can act:

  • On nearby cells (paracrine signaling).

  • On the same cells that produce them (autocrine signaling).

• Target cells have specific receptors that bind to hormones and initiate a response.

Animal Endocrine System

Hormones in Animals

• The animal endocrine system consists of various glands, such as the:

  • Pituitary gland

  • Thyroid gland

  • Adrenal glands

  • Reproductive glands

• These glands secrete hormones into the bloodstream.

• Animal hormones regulate:

  • Growth

  • Metabolism

  • Reproduction

  • Other physiological processes

Major Animal Hormones

1. Insulin – Regulates blood sugar levels by promoting glucose uptake by cells.

2. Thyroxine – Controls metabolism and growth.

3. Adrenaline – Triggers the "fight or flight" response in stressful situations.

4. Estrogen & Testosterone – Regulate reproductive functions and secondary sexual characteristics.

Mode of Transport in Animals

• Animal hormones are transported through the bloodstream to reach target cells.

• Endocrine glands release hormones, which are carried by the blood to specific tissues or organs.

Target Cells in Animals

• Animal hormones act on specific target cells that have receptors for the hormone.

• These receptors are usually located on the surface or inside the target cells.

• When a hormone binds to its receptor, it triggers biochemical reactions, leading to a physiological response.

Chemical and Nervous Control

Chemical Control

• Both plant and animal endocrine systems rely on chemical control to regulate physiological processes.

• Hormones act as chemical messengers, coordinating and integrating various functions within the organism.

• They can be produced in response to internal or external stimuli and can have long-lasting effects on the target cells.

Nervous Control in Animals

• In addition to the endocrine system, animals have a well-developed nervous system that allows for rapid and precise control of physiological processes.

• Nervous control involves:

  • The transmission of electrical signals (nerve impulses) through neurons.

  • These impulses travel along nerve fibers and allow for quick responses to stimuli.

Differences Between Nervous and Endocrine Control

• The endocrine system regulates long-term processes.

• The nervous system is responsible for immediate responses.

• Example: If you touch a hot object, your nervous system will quickly send a signal to your muscles to withdraw your hand.

Conclusion

• Both plants and animals have mechanisms to regulate and control physiological processes.

• Plants rely on hormones transported through vascular tissues for endocrine control.

• Animals have a well-developed endocrine system that uses hormones transported through the bloodstream.

• Additionally, animals have a nervous system that allows for rapid and precise control of physiological processes.

• Understanding these systems helps us appreciate the complexity of life and how organisms adapt and respond to their environment.

Lesson 9: Plant and Animal Immune System and Mechanism of Defense

Both plants and animals have immune systems that help protect them from pathogens and diseases. While there are similarities between the two systems, there are also significant differences.

Introduction

Plant Immune System – Key Features

a. Physical Barriers

• Plants have physical barriers such as the cell wall and waxy cuticle, which act as the first line of defense against pathogens.

b. Pattern Recognition Receptors (PRRs)

• Plants have PRRs that recognize specific pathogen-associated molecular patterns (PAMPs) and trigger immune responses.

c. Hormonal Signaling

• Plants use hormones like salicylic acid and jasmonic acid to regulate immune responses and coordinate defense mechanisms.

d. Systemic Acquired Resistance (SAR)

• When a plant is infected, it can develop SAR, which allows it to respond more effectively to future infections.

Plant Immune System – Mechanisms of Defense

a. Pathogen-Associated Molecular Pattern (PAMP)-Triggered Immunity (PTI)

• When PRRs recognize PAMPs, PTI is activated, leading to the production of antimicrobial compounds and reinforcement of cell walls.

b. Effector-Triggered Immunity (ETI)

• If a pathogen manages to overcome PTI, plants can activate ETI, which involves the recognition of specific pathogen effectors and a stronger immune response.

Animal Immune System – Key Features

a. Physical Barriers

• Animals have physical barriers such as the skin and mucous membranes, which prevent pathogens from entering the body.

b. Innate Immunity

• Animals have an innate immune system that provides immediate defense against pathogens through mechanisms like phagocytosis and inflammation.

c. Adaptive Immunity

• Animals also have an adaptive immune system, which can recognize and remember specific pathogens, providing long-term protection.

Animal Immune System – Mechanisms of Defense

a. Innate Immune Response

• The innate immune system responds to pathogens through mechanisms like:

  • Phagocytosis

  • Natural killer cells

  • Release of antimicrobial proteins

b. Adaptive Immune Response

• The adaptive immune system involves the activation of:

  • B cells – Produce antibodies.

  • T cells – Target specific pathogens for destruction.

Comparison Between Plant and Animal Immune Systems

1. Physical Barriers

• Both plants and animals have physical barriers that prevent pathogens from entering their bodies.

• Plants: Cell wall and waxy cuticle.

• Animals: Skin and mucous membranes.

2. Recognition of Pathogens

• Plants: Use PRRs to recognize specific pathogen-associated molecular patterns (PAMPs).

• Animals: Have receptors that recognize antigens on pathogens.

3. Hormonal Signaling

• Plants: Use salicylic acid and jasmonic acid to regulate immune responses.

• Animals: Use cytokines and chemokines for immune signaling.

4. Immune Response Activation

• Plants: Activate PTI and ETI in response to pathogen recognition.

• Animals: Activate innate and adaptive immune responses.

5. Memory and Specificity

• Animals: Have an adaptive immune system that can remember specific pathogens and mount a targeted response upon reinfection.

• Plants: Do not have a memory-based immune response.

Conclusion

• While both plants and animals have immune systems to protect themselves from pathogens, there are notable differences in their mechanisms of defense.

• Plants rely on:

  • Physical barriers

  • Pattern recognition receptors

  • Hormonal signaling

• Animals have:

  • Physical barriers

  • Innate immunity

  • Adaptive immunity

Understanding these differences provides insights into the fascinating world of immune systems in the natural world.

Lesson 10: Plant and Animal Nervous System with Sensory and Nervous Mechanisms

The nervous system is responsible for coordinating and controlling the activities of organisms.
While animals have a well-developed nervous system, plants also possess a unique mechanism to respond to their environment.

Introduction

• Plants do not have a centralized nervous system like animals.

• Instead, they have a decentralized network of cells that can transmit electrical signals.

• This network is known as the plant’s "nervous system".

Plant Nervous System – Main Components

a. Sensory Cells

• Plants have specialized sensory cells that can detect various stimuli such as:

  • Light

  • Gravity

  • Touch

  • Chemicals

• These cells are usually located in the roots, stems, leaves, and flowers of the plant.

• Examples:

  • Photoreceptors like phytochromes, cryptochromes, phototropins, and UV-B receptors.

b. Electrical Signaling

• When a sensory cell detects a stimulus, it generates an electrical signal.

• This signal can travel through the plant's interconnected cells, allowing the plant to transmit information from one part to another.

c. Chemical Signaling

• Plants also use chemical signals, such as hormones, to communicate and coordinate their responses.

• These chemical signals can be produced in one part of the plant and transported to other parts to trigger specific responses.

Animal Nervous System – Main Components

Animals have a centralized nervous system, which consists of the:

• Brain

• Spinal cord

• Nerves

The animal nervous system can be divided into two main parts:

1. Central Nervous System (CNS)

• Includes the brain and spinal cord.

• Responsible for processing and integrating information received from the sensory organs and coordinating the body's responses.

2. Peripheral Nervous System (PNS)

• Consists of nerves that connect the CNS to the rest of the body.

• Transmits signals between the CNS and various organs, muscles, and glands.

Sensory Mechanism in Plants and Animals

Both plants and animals have sensory mechanisms that allow them to detect and respond to stimuli in their environment.
Here are some key differences between the sensory mechanisms of plants and animals:

Plants:

• Sensory cells are distributed throughout their tissues.

• Detect stimuli such as light, gravity, touch, and chemicals.

• Generate electrical signals in response to stimuli.

• Use chemical signals (e.g., hormones) to coordinate their responses.

Animals:

• Have specialized sensory organs such as:

  • Eyes

  • Ears

  • Nose

  • Skin

• Sensory organs convert stimuli into electrical signals that are processed by the nervous system.

• Have a wide range of sensory abilities, including:

  • Vision

  • Hearing

  • Smell

  • Taste

  • Touch

Nervous Mechanism in Plants and Animals

The nervous mechanisms in plants and animals differ significantly due to structural differences in their nervous systems.

Plants:

• Decentralized nervous system, with interconnected cells transmitting electrical signals.

• Electrical signals can travel in any direction and can be transmitted through the entire plant.

• Use chemical signals (e.g., hormones) to coordinate responses.

• Responses to stimuli are generally slower compared to animals.

Animals:

• Centralized nervous system, with the brain and spinal cord processing and integrating information.

• Nerves transmit electrical signals in a specific direction:

  • From sensory organs to the CNS.

  • From CNS to muscles and glands.

• Responses to stimuli are generally faster compared to plants.

Conclusion

• While plants and animals have different nervous systems and sensory mechanisms, both have evolved unique ways to detect and respond to their environment.

• Plants rely on a decentralized network of cells and chemical signaling.

• Animals have a centralized nervous system and specialized sensory organs.

• Understanding these differences helps us appreciate the diverse ways in which living organisms interact with their surroundings.