Animal and Plant Biological Processes

Biological Processes

• The objectives are to compare and contrast biological processes such as reproduction, development, nutrition, gas exchange, transport/circulation, regulation of body fluids, chemical and nervous control, immune systems, and sensory and motor mechanisms in plants and animals.
• Key biological processes in plants and animals covered: reproduction, development, nutrition, immune systems, gas exchange, transport/circulation, regulation of body fluids, chemical and nervous control, and sensory and motor mechanisms.

Reproduction

• Animals and plants can reproduce sexually or asexually
• Sexual reproduction is more common in animals
  • Advantage: Genetically diverse offspring
  • Disadvantage: Requires more time and energy
• Asexual reproduction is more common in plants
  • Advantage: Reproduce quickly and with little energy
  • Disadvantage: Lack of genetic diversity
• Sexual reproduction, mediated by gametes, involves the formation of a zygote
• Asexual reproduction does not involve the fusion of female and male gametes, instead relying entirely on mitotic division
• Gametes are reproductive cells like ova and sperm
• A zygote is a fertilized egg cell
• Mitotic division: where a parent cell divides into two identical daughter cells.

Animal Reproduction

• Fertilization is the process where male and female gametes fuse to create a zygote.
• Hermaphroditism is defined as a sexually reproducing organism that produces both male and female gametes; this is mostly seen in invertebrates (ex. worms, moss animals, snails, slugs etc)
• Fertilization may either be internal or external
  • Internal: Mammals, Birds, Reptiles
  • External: Fish, Amphibians
• Hermaphroditism: Earthworms, Snails
• Sequential Hermaphroditism: Clownfish Wrasse

Asexual Reproduction in Animals

• Budding is when offspring grow from outgrowths (e.g., sponges, cnidarians, and corals – most invertebrates)
• Fragmentation is when a parent organism breaks into fragments (e.g., starfish, annelid worms, corals)
• Parthenogenesis occurs when female offspring develop from an unfertilized egg (e.g., some lizards, bees, aphids)
• Sea anemones, aphids, and other animals are able to reproduce both ways, sexually and asexually

Plant Reproduction

• Pollination is pollen grains of male gametes are transferred from the anther to the female portion (stigma) of a flower to enable fertilization for seed production

Asexual Reproduction in Plants

• Vegetative Propagation: Offspring grow from a part of the parent plant (e.g., Garlic, Onion, Potato, Ginger, and Strawberry)
• Fragmentation: parent organism breaks into fragments (e.g., liverworts and mosses)
• Spore Formation: mosses, and ferns
• Strawberry and Daffodils: Seed and Bulb
  • Daffodils- Seed and Bulb
  • Strawberry- Seed and Runners
• Alternation of Generations: the alternation of a sexual phase and an asexual phase in the life cycle of an organism

Reproduction in Unicellular Organisms

• Unicellular organisms reproduce through binary fission, a cell splitting into two or more.
• Binary fission: Leishmania causes Kala-azar, more common in Brazil, East Africa & India.
• Symptoms for Kala-azar may include Amebiasis Symptoms loose feces (poop), stomach pain, and stomach cramping. Infection is caused by amoeba contaminated water or food
• Multiple fission: Plasmodium causes Malaria
• Symptoms for Malaria include: fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness, may cause anemia and jaundice
• Palawan: most malaria-endemic province

Development

• Development: complex embryonic development, distinct life stages and a fixed size at maturity in Animals
• Plants feature indeterminate growth primarily through the activity of the growth of roots, stems, and leaves (indeterminate).
  • Animals feature a determined growth pattern with a defined lifespan
  • Plants feature indeterminate growth, primarily through the activity of meristems

Animal Development Stages

• Fertilization
• Cleavage
• Gastrulation
• Organogenesis
• Differentiation and Growth

Plant Development Stages

• Seed Germination
• Seedling Stage
• Vegetative Growth
• Reproductive Growth (Flowering)
• Growth and Maturation (Fruit Development)

Terms to Remember Regarding Development

• Fertilization: Fusion of sperm and egg which results in a zygote
• Cleavage: A period of rapid cell division without growth
• Morphogenesis: The formation and differentiation of tissues and organs.
• Gastrulation:Embryonic development from blastula (Single-celled layer embryo)to gastrula (three-layered embryo)
• Organogenesis: The process of formation of organs from three germ layers (ectoderm, endoderm, mesoderm) of gastrula.
• Indeterminate Growth: Plant growth in which the main stem continues to elongate indefinitely without being limited by a terminal inflorescence or other reproductive structure

Fertilization Development types

• Oviparous: Egg-laying (Birds, most fish, amphibians)
• Viviparous: Live-bearing (Mammals, some sharks)
• Ovoviviparous: Egg-hatching inside the body (Some reptiles (snakes), sharks) develops inside the female's body, but the embryos rely on the yolk

Nutrition

• Animals are heterotrophic organisms.
  • They obtain their food by consuming other organisms
  • Nutrients are obtained through ingestion, digestion, absorption, and assimilation
  • Animals also feature a system to extract nutrients (digestive system)
• Plants are autotrophic organisms.
  • Produce food through photosynthesis
  • Nutrients are from the soil, water, and air
• Autotrophs (producers) are organisms that make their food from raw materials and energy (e.g., plants, algae, and some types of bacteria)
• Heterotrophs (consumers) cannot produce their food, so they derive nutrition from other sources of organic carbon, mainly plant or animal matter(e.g., dogs, birds, fish, and humans)
• Food Chain- Three Trophic Levels
  • First- Autotrophs (Primary Producers)
  • Second and Third- Heterotrophs
  • Herbivores (2nd Level- Primary Consumers)
  • Carnivores and Omnivores (3rd Level- Secondary Consumers)

Animal Nutrition

• Animals Require (Water, Oxygen)
  • Macronutrients: Carbohydrates, Proteins, Fats
  • Micronutrients: Vitamins, Minerals, Fiber

Plant Nutrition

• Plants Require (Water, Carbon Dioxide)
  • Macronutrients: C, H, O, N, P, K, Ca, Mg, S
  • Micronutrients: Fe, Mn, Zn, Cu, B, Mo, CI
• The roots are used to absorb water and minerals
  • Two Pathways (from soil to conducting tissues - xylem)
    • Symplast Route- through p
    • Apoplast Route- through cell walls
• Vascular Tissues
  • Xylem- Transport of water and dissolved minerals- from roots to other parts of the plant.
  • Phloem- Transport of food (mainly sucrose) from the leaves (where it is synthesized) to other parts of the plant

Immune System

• Skeletal, Circulatory, and Immune-Lymphatic Systems work together immunity in humans

Animal Immune Systems

• Plants lack defender cells and adaptive immune system.
• Aninnate and adaptive immune system is employed.
  • Innate Immunity (present in all animals) that is nonspecific - not directed against specific invaders but against any pathogens that enter the body
  • Adaptive Immunity (only present in Vertebrates) is pathogen-specific and consists of mechanisms that recognize specific threats and remember previous exposures to specific microbes

Animal Innate and Adaptive Immunity

• Innate Immunity is aided by different types of defensive barriers:
  • Anatomic or Physical Barriers (skin and mucous membrane, cilia)
  • Chemical Barriers (Acidic Environments, Enzymes, Complement Proteins) e.g., low pH in the stomach, sweat, lysosome in tears, and saliva
  • Physiological Barriers (Fever, Coughing and Sneezing, Inflammation, Mucus Production)
• Cellular Defenses (Phagocytes- immune cells that engulf and digest pathogens, Natural Killer Cells- induce apoptosis or cell death, Mast Cell- inflammation)
• Pattern Recognition Receptors (PRRs) (specialized proteins that recognize patterns in pathogens- called PAMPs)
• The Complement System (antimicrobial proteins)
• Adaptive Immunity is comprised of two arms:
  • Cellular Immunity, cell-mediated, occurs inside infected cells and is mediated by T lymphocytes.
  • Humoral Response is antibody-mediated for the production and secretion of antibodies or immunoglobulins (Plasma B Cells) against specific antigens. There are two main types of lymphocytes: B cells and T cells.
• B cells produce antibodies to attack invading bacteria, viruses, and toxins
• T- cells destroy the body's own cells that have themselves been taken over by viruses or become cancerous.

Types of Blood Cells (leukocytes) responsible for immunity

• The blood cell mainly responsible for adaptive immunity is mainly responsible for immunity which is the lymphocyte.
  • Neutrophils
  • Eosinophils
  • Basophils
  • Monocytes
  • Lymphocytes (T cells, B cells, and Natural Killer Cells)
• The main types of Antibodies, also known as Immunoglobulins (Igs):
  • IgM- First antibody produced, coats the pathogen and promotes endocytosis by macrophages.
  • IgG- The major antibody, activates the other parts of the immune response and leads to neutralization and destruction of pathogens.
  • IgA- use for mucosal immune response, prevents pathogens from crossing the epithelium
  • IgE- activates mast cells and leads to the production of histamine ( allergic reactions)
  • IgD- functions to signal B cells to be activated

Plant Immune System

• Plants do not have an adaptive immune system or defender cells but innate immunity through microbe recognition and systematic signals
• Primary Defense Mechanisms: plant's first line of defense against pathogens that include preformed barriers and basal immune responses:
  • Physical Barriers such as:
    • Waxy cuticle and cell walls that prevent pathogen entry.
    • Stomatal closure to block pathogen penetration.
  • Chemical Barriers: Preformed antimicrobial compounds (e.g., saponins, phytoanticipins).
  • PAMP-Triggered Immunity (PTI): occurs only when a pathogen breaches physical barriers, pattern recognition receptors (PRRs) detect pathogen-associated molecular patterns (PAMPs) and trigger general immune responses, such as:
    • Reactive oxygen species (ROS) production.
    • Cell wall reinforcement.
    • Expression of defense-related genes.
• Secondary (Induced) Immunity- Activated after an initial pathogen attack:
  • Effector-Triggered Immunity (ETI) - recognition of specific effectors secreted by pathogens, leading to a strong immune response, including hypersensitive response (HR) and Systemic Acquired Resistance (SAR). -Induction by PTI or ETI provides broad-spectrum immunity across the plant primarily through salicylic acid signaling.
• Hypersensitive Response (HR)- Leads to cell death (necrosis) around the source of the invasion, coupled with the secretion of plant hormones (salicylic acid, ethylene)
• Systematic Acquired Response (SAR)- temporary broad-ranging resistance where plants activate defense responses more quickly and effectively the second time they encounter a pathogen attack

Plant Secondary (Induced) Immunity

• Triggered by beneficial microbes like rhizobacteria, priming the plant's immune system for stronger responses. Key hormones are Jasmonic acid and ethylene( ISR by beneficial microbes like rhizobacteria)
• Chemical Defense: Production of antimicrobial compounds, phytoalexins, and protease inhibitors.