Plant and Animal Gas Exchange

Plant Gas Exchange

• Plants use their leaves to obtain necessary gases.
• Respiration requires oxygen, while photosynthesis utilizes carbon dioxide.

Respiration

• Occurs continuously in plants, providing energy.
• Photosynthesis only occurs during daylight.
• Respiration produces carbon dioxide.

Photosynthesis

• A chemical process where plants use light energy to convert carbon dioxide and water into glucose and oxygen.
• Chlorophyll, a green pigment in leaves, absorbs light energy.
• Chlorophyll is found in chloroplasts, specifically in palisade cells on leaf surfaces.
• Carbon dioxide enters leaves through stomata.
• Water is transported from roots to leaves via the xylem.
• Oxygen is a byproduct, with some reused for plant respiration.

Animal Gas Exchange

• Gas exchange follows a similar pattern in animals and plants involving oxygen and carbon dioxide diffusion.
• Simple animals exchange gases directly with their environment.
• Complex animals, like mammals, exchange gases between the environment and their blood.
• Blood carries oxygen and transports carbon dioxide.

Transport and Circulation

• Transport and circulation are essential for substance movement within organisms, and plants plus animals evolved different methods to fulfill the process
• Plants lack a circulatory system.
• Xylem transports water and minerals from roots.
• Phloem transports nutrients and sugars from leaves.
• Passive transport involves diffusion, osmosis, and capillary action.
• Animals have a circulatory system with a heart and blood vessels.
• Blood carries oxygen, nutrients, hormones, and wastes.
• Blood vessels: arteries, veins, and capillaries facilitate transport.
• Active transport relies on the heart pumping blood.

Types of Signals in Plants and Animals

Chemical Control

• Plants use hormones like auxins, gibberellins, ethylene, and cytokinin.
• Chemical control regulates growth and responses to light, gravity, and water in plants.
• Animals use hormones from glands such as insulin, adrenaline and thyroid hormones.
• Chemical controls regulate physiological processes like growth, metabolism, and reproduction in animals.

Nervous Control (Animals)

• Involves electrical (action potentials) and chemical signals (neurotransmitters).
• Transmitted through neurons for rapid responses to stimuli of environmental changes such as pain or temperature.

Plant Electrical Signals

• Plants produce electrical signals, like action potentials.
• Signals travel through the vascular system assisting in stimuli response regulation but slower than in animals.

Signal Transmission in Plants and Animals

Plants

• Signals move via the vascular system (xylem and phloem).
• Hormones transport between cells.
• Electrical signals spread through conductive tissues, being slower than in animals.

Animals

• Neurotransmitters transmit signals across synapses.
• Electrical impulses travel neurons quickly
• This allows rapid communication between the brain, spinal cord, and target tissues.
• The endocrine system uses hormones traveling via the bloodstream to target organs.

Speed and Specificity of Response

Plants

• Slower chemical control via the vascular system leads to gradual responses.
• Hormonal signals affect broad areas, causing slower responses.

Animals

• Rapid nervous control via neurons allows quick, localized responses, like muscle contractions and reflexes.
• Hormonal signals can be fast, but slower/more systemic compared to nervous responses.

Coordination of Responses

Plants

• Largely hormonal.
• Hormones promote cell growth (phototropism) and abscisic acid controls stress responses, such as closing stomata during drought.
• Lacking a central nervous system, responses are diffuse/systemic like focusing on growth and survival as response to environmental cues.

Animals

• Involves the nervous (immediate, localized responses) and endocrine systems (slower, longer-term regulation).
• The nervous system processes sensory information quickly; the endocrine system regulates metabolism and growth.

Summary Comparison of Plants and Animals

Signal Type

• Plants utilize hormones like auxins and gibberellins.
• Animals utilize hormones like insulin and adrenaline plus neurotransmitters.

Signal Transmission

• Plants use the vascular system (xylem, phloem) and electrical signals in cells.
• Animals use the nervous system (neurons) and bloodstream (for hormones).

Speed of Response

• Plants show slow, gradual responses like growth.
• Animals feature fast, immediate responses like reflexes and muscle contraction.

Specificity

• Plants: Less specific and often systemic.
• Animals: High specificity and localized.

Coordination

• Plants utilize hormonal control for growth and stress responses.
• Animals depend upon the nervous system for quick responses, with hormonal controls for long term regulations.

Immune systems

• Both plants and animals protect against pathogens via different pathways.
• Animals rely heavily on the nervous system.
• Plants rely on growth and response to environment interactions.

Animal Immune System

Innate Immunity

• The primary defense.
• Involves physical barriers such as skin.
• Includes cells like phagocytes.
• Includes molecular responses such as cytokines and interferons.
• Provides a non specific defense.

Adaptive Immunity

• Specific immune response.
• Production of antibodies
• Activation of T-cells
• Memory cells
• Faster response to pathogens on re-exposure.
• Highly specialized

Plant Immune System

Physical Barriers

• Cell walls
• Bark
• Waxy cuticles
• Prevent pathogen entry

Innate Immunity

• Lacks cells in animals.
• Detects pathogens using pattern recognition receptors (PRRs) that identify pathogen-associated molecular patterns (PAMPs).

Hypersensitive Response (HR)

• When a pathogen is detected, programmed cell death at the infection site occurs.
• Prevents spread.

Systemic Acquired Resistance (SAR)

• Defense mechanism.
• Enhances resistance to future infections.

Key Differences in Animal and Plant Immune Systems

Memory:

• Animals have adaptive immunity, that allows them to fight previously encountered pathogens
• Plants lack memory.
• Plants rely on broad innate responses.

Specialization:

• Animal immune systems are tailored to specific pathogens
• Plant immune responses are generalized.

Sensory and Motor Mechanisms Overview

• Sensory and motor mechanisms allow organisms to interact and respond to the environment.
• Plants plus animals use different mechanisms and their ways towards stimuli varies.

Sensory Mechanisms in Plants

• Plants respond to stimuli through tropisms and hormonal signals.
• A nervous system is not required

Sensory Examples

• Phototropism: growth toward light.
• Gravitropism: Roots grow downward, stems grow upward.
• Thigmotropism: touch responses, e.g., vines wrapping around supports.
• Chemotropism: chemical responses, e.g., roots growing toward nutrients.
• Responses are driven by auxins, regulating growth direction

Sensory Mechanisms in Animals

• Complex sensory organs detect external stimuli.

Sensory receptors

• Send signals to the brain via sensory neurons.

Examples

• Visual: eyes detect light
• Auditory: earsdetect sound waves.
• Tactile: skin detects touch, temperature, and pressure.
• Olfactory: nose detects chemical signals (smell).
• Gustatory: tongue detects chemicals for taste.
• These sensory inputs allow animals to navigate, find food, avoid danger, communicate

Motor Mechanisms in Plants

• Primarily involve growth responses (tropisms).
• Plants respond to environmental factors via directional growth.
• Chemical that signaling from hormones such as auxins guides the plant.
• Plants don't have muscles or a nervous system

Motor Mechanisms in Animals

• Involves movement by muscles or glands.
• The nervous system coordinates responses.

Example include

• Muscle contraction: response to signals from brain/spinal cord.
• Reflex arcs: rapid responses without brain involvement.
• Voluntary movement: complex actions requiring brain activity.

Differences for Plants

Sensory responses

• Mediated by hormones (auxins).

Motor responses

• Growth changes.

Differences for Animals

Sensory input

• Specialized sensory organs.

Motor responses

• Controlled by the nervous system, involving muscles/glands

Conclusion of Senses and Motors

• Plants plus animals have sensory and motor.
• Animals depend on nervous systems.
• Plants rely on growth and chemical signaling to respond to environmental factors like light, gravity, and touch.

Homeostasis

• Maintains stable internal environment.
• Ensures condition for proper cell, tissue, and organ function.

Homeostasis Regulation

• Temperature Regulation (Thermoregulation):
  • Endotherms regulate internal temperature through metabolic processes.
  • Ectotherms rely on external heat.
• Water Balance (Osmoregulation):
  • Regulate water/salt to avoid dehydration/overhydration.
  • Marine animals adapt to high salt seawater.
• pH Regulation (Acid-Base Balance):
• Maintain stable pH using buffer systems
• Use the respiratory system for pH via carbon dioxide

Adaptations

• Environments shape homeostasis.
• Differing environments shape organisms homeostasis.
• Desert plants store water and minimize water loss.
• Animals in colder climates develop thick fur.

Importance

• Homeostasis is critical for survival.
• Dysfunction or death can result as result of change.
• Body homeostasis maintains internal stability.