BIO 5 CHAPTER 3 PDF - Adaptation & Natural Selection

THE ORGANISM AND ITS ENVIRONMENT CHAPTER 3 | GENERAL ECOLOGY MS. BIANCA JUACALLA FIRST SEMESTER A.Y. 2024-2025 DO IT FOR THE GLORY OF GOD! ADAPTATION & NATURAL SELEC...

THE ORGANISM AND ITS ENVIRONMENT CHAPTER 3 | GENERAL ECOLOGY MS. BIANCA JUACALLA FIRST SEMESTER A.Y. 2024-2025 DO IT FOR THE GLORY OF GOD! ADAPTATION & NATURAL SELECTION Adaptations are a product of natural selection. What is Natural Selection? ❖ Differential success of individuals within the population that results from their interaction with the environment. Conditions 01. Variation among individuals within a population is “heritable”. 02. Variation results in differences in survival and reproduction. ❖ Darwin’s statement: Some will leave more offspring than others (can pass more traits). More fit than the others Some will leave fewer offspring than others. Less fit than the others Fitness is associated with natural selection and evolution. Selected for: In favor Selected against: Not in favor May cause death and decline in reproduction. What is Adaptation? ❖ Heritable trait ❖ Evolved over a period of time ❖ Maintains or increase the fitness Traits that enable organisms to survive, grow, and reproduce. Limits the ability of an organism to successfully function in other environments. DOCUMENTATION OF NATURAL SELECTION ★ Species: Medium ground finch ★ Location: Daphne Major (in Islet of Galapagos Island) ★ Target observation: Frequency of beak depth adapted 1970s 1977 The Galapagos Islands receive abundant rainfall. The Galapagos Islands experienced drought, “El Supported abundance of seeds. Nino”. Population grows Decline of nuts (Small/Medium) Decline of population ○ Death ○ Migration Different fitness is a function of difference in phenotypes (physical trait). ★ Therefore, large birds had the highest rate of survival. Target of Selection Trait that selection acts directly upon. Beak size Selective Agents Environmental cause of fitness difference. Abundance and distribution of food resources Due to heavy rainfall and drought  TYPES OF SELECTION Legend: ★ X-axis: Phenotypes or Traits ★ Y-axis: Frequency or Number of population/individuals ★ Dashed line: Normal distribution of population ★ Dotted line: Distribution of population after being subjected to natural selection STABILIZING SELECTION ❖ Mean phenotype in a population exhibits the highest relative fitness and the original distribution of phenotypes is shifted to center. ❖ Mean phenotype is selected by natural selection. Low Mid High ❖ Example: Height of Trees and Optimal Abundance Low: Affected by light distribution, May not grow relatively high Mid: Mean Phenotype; “chill lang”, Highest survival rate Adequate sunlight, unaffected by winds High: Affected by winds May falter due to strong winds above  ❖ One extreme phenotype exhibits the highest relative fitness and original distribution of phenotype is shifted to one side ❖ Example: A population of giraffe migrates to a new habitat with only large trees. Low: Unfavored phenotype Can not eat large trees; may not survive Mid: Unfavored phenotype Can not eat large trees; may not survive High: Favored phenotype due to height Can eat large trees as food resource Low Mid High DIRECTIONAL SELECTION DISRUPTIVE SELECTION ❖ Extreme values of phenotype exhibit the highest relative fitness and the result is a bimodal distribution of phenotypes. ❖ Example: Three populations of rodents with white, black, and brown fur live in a rocky (white, black, brown) place. A collection of brown rocks took place and made camouflage ineffective for brown rodents and prone to predation. White: Favored phenotype for camouflage in white rocks Highest survival rate Brown: Unfavored phenotype for camouflage due to the absence of brown rocks Lowest survival rate Black: Favored phenotype for camouflage in black rocks Highest survival rate  ORGANISM’S ADAPTATION What are the types of adaptations? ❖ It can be morphological, behavioral, or physiological, and can even be broken down to further specific categories. ❖ All given types: 01. Temperature 02. Acquiring Energy and Nutrients 03. Social Interaction 04. Behavioral Patterns 05. Communication and Senses 06. Morphology 07. Reproductive Strategies TEMPERATURE DESERT PLANTS ❖ Environmental Condition Dry and Arid Minimal water availability ❖ Adaptations 01. Reduce conductive heat gain from ground. ○ Conductive heat is heat transfer through direct contact with each other. ○ Therefore to reduce this, the plant body is usually raised away from the surface. 02. Increase rates of convective cooling, ○ Convective cooling is heat transfer from one place to another due to the molecular movement of fluids such as air or liquid. ○ Therefore, leaves of most plants are small and with huge spaces so that wind can flow through the spaces. 03. Reduce rates of radiative heating. ○ Reduction of transfer of heat directly from the sun. ARCTIC & ALPINE PLANTS ❖ Environmental Condition Cold-mountain regions ❖ Adaptations 01. Increase the conductive heat gain from ground. ○ Grow close to the ground in cushion-growth form. ○ This will absorb heat from the ground. 02. Reduce rates of convective cooling. ○ Due to their cushion-growth form, the flow of wind that may cool it off is lessened. 03. Increase rates of radiative heating. ○ More radiation is absorbed. TROPICAL ALPINE PLANTS ❖ Environmental Condition Warm in the morning; Cold at night ❖ Adaptations 01. Retain dead leaves. ○ Act as insulation 02. Retain large volumes of water. ○ Reservoir of water; Due to water’s high specific heat 03. Leaves act as parabolic mirrors. ○ Protect the bud from freezing. THERMOREGULATION ★ Poikilotherms ○ Greek: Poikilo = “Irregular” or “Varied” or “Changing” ○ Animals with body temperature adjust depending on the environment. Body temperature varies with the environment. They don't actively regulate their internal temperature. ★ Homeotherms ○ Greek: Homoios = “Constant” or “Similar” ○ Animals with constant body temperature. Maintain a constant body temperature regardless of the environmental conditions. ★ Endotherms ○ Greek: Endon = “Within” or “Inside” ○ Animals’ heat is produced or comes within the body. Generate their own body heat through metabolic processes to maintain a stable internal temperature. ★ Ectotherms ○ Greek: Ektos = “External” or “Outside” ○ Animals gain or acquire heat from the surroundings. Rely on external environmental heat sources to regulate their body temperature. ★ Combinations ○ Homeothermic Endotherms Maintain a stable internal body temperature regardless of environmental changes. Generate heat internally (endothermic) and regulate their temperature precisely (homeothermic). Birds Mammals ○ Poikilothermic Ectotherms Their body temperature fluctuates with the environment (poikilothermic). Depend on external sources of heat for thermoregulation (ectothermic). Reptiles Insects Fish Amphibians Invertebrates ○ Poikilothermic Endotherms Hibernating Animals; produce heat and adjust heat based on the environment. Typically generate heat internally but allow their body temperature to vary with the environment during hibernation. ○ Homeothermic Ectotherms Certain animals that maintain body heat externally, like some aquatic organisms, can maintain a constant temperature by moving through different water temperatures (homeothermic via external means). Maintain body heat from the water through moving from one place to another. ECTOTHERMS AND ENDOTHERMS ADAPTATION Ectotherms 01. Basking in the sun. a. Can absorb heat from the sun to raise their body temperature For processes like digestion and mobility b. Example: Lizards, Snakes 02. Varying pigmentation. a. Can adjust their skin color or pigmentation to regulate heat absorption. Darker colors absorb more heat, which is useful in cooler conditions Lighter colors reflect heat, helping them stay cooler in warm environments b. Example: Chameleon, Insects Endotherms 01. Thermogenesis a. Process of producing metabolic heat. b. Heat generated from biochemical processes. Glycolysis: Breaking down glucose to produce energy. Fatty acid metabolism: Breaking down fats to generate heat. 02. Shiver a. Muscle contraction produces heat. Involuntary mechanism of the muscle. 03. Insulating a. To minimize heat loss. Birds: Fluff up their feathers, creating an insulating layer of trapped air, which helps maintain body heat. Mammals: Develop goosebumps (piloerection), where hair stands up to trap heat close to the skin. Aquatic Mammals: Have a thick layer of blubber (fat deposits) to insulate from cold water. While humans also have fat, it is less effective for insulation than in aquatic mammals. 04. Countercurrent Heat Exchange a. Circulatory adaptations b. Allow heat to be transferred from blood vessels containing warm blood to vessels containing cooler blood. Arteries: Carry oxygenated (warmer) blood away from the heart and lungs. Veins: Carry deoxygenated (colder) blood from other parts of the body to the heart. c. If blood vessels are not close to each other, heat is dissipated to the external environment. d. This process allows warm blood entering the limb to transfer heat directly to blood flowing back into the body. ❖ Countercurrent heat exchange is used by some animals to conserve heat. It involves the transfer of heat between two flowing fluids (usually blood) that are moving in opposite directions. This process helps organisms regulate their body temperature, particularly in cold environments, by minimizing heat loss. ❖ Process Arteries carrying warm blood from the core of the body are located very close to veins carrying cooler blood from the extremities. As the warm arterial blood flows towards the extremities, heat is transferred to the cooler venous blood flowing in the opposite direction. This happens through conduction, as the temperature gradient between the two vessels allows heat to move from the warmer to the cooler side. By the time the arterial blood reaches the extremities (such as the feet or flippers), it is much cooler, reducing the amount of heat lost to the environment. Meanwhile, the venous blood returning to the core is warmed by this exchange, maintaining a more consistent body temperature. ❖ Reasons To reduce heat loss and conserve energy. Retain warmth in their core body while minimizing heat loss from their extremities. 05. Air breathing a. Conserve and minimize heat loss. 06. Vasoconstriction a. The narrowing of capillaries (small blood vessels) near the skin's surface. b. Blood flows from the heart but bypasses the skin's surface, reducing the amount of blood exposed to the cooler external environment. c. Blood returns to the heart without losing much heat. To conserve body heat by limiting heat loss through the skin. Useful in cold conditions when maintaining core body temperature is essential for survival. 07. Vasodilation a. The widening of capillaries near the skin's surface. b. Blood flow increases to the skin, allowing heat to be transferred from the body to the environment. c. The larger surface area and increased blood flow facilitate heat dissipation into the surroundings. To release excess body heat in warm conditions, preventing overheating. Allows the body to cool down by transferring heat from the core to the environment for temperature regulation. 08. Increased heart rate and blood flow a. To release body heat b. Axillary bass (underarm) c. Example: Jack rabbit and Fennec fox has thin skin in their ears, has no fur, has most blood vessels 09. Evaporative cooling system a. Horse: Sweating (Overexercised if bubbles are seen) Release protein called “latherin” to pump sweat produced by its body b. Dogs: Panting and excess saliva; no sweat c. Cats: Licking of body to lose body heat d. Kangaroo: Sweats during exertion but licks body when experiencing heat during at rest 01. Torpor a. “Deep sleep” ; “State of unconsciousness” b. A short-term state of reduced metabolic activity and body temperature for small animals. Lasts for hours or a day (usually overnight or during extreme conditions). To conserve energy during periods of cold (daily torpor) or food scarcity. Can occur frequently (daily or seasonally). Can quickly return to its normal state if conditions improve. c. Example: hummingbirds enter torpor overnight to conserve energy. 02. Hibernation a. A prolonged, deep state of torpor that lasts for an extended period during cold weather (winter). Lasts for weeks to months. To survive during winter by significantly reducing metabolic rate, heart rate, and body temperature. Hibernating animals drastically reduce energy consumption. Body temperature drops near ambient levels, and heart rate slows significantly. Awakening is infrequent and often prompted by rising external temperatures. b. Example: Bears, ground squirrels, and some reptiles when food is scarce and temperatures are low. 03. Estivation a. A state of dormancy similar to hibernation, but it occurs during hot, dry periods. Can last for weeks to months during summer or drought conditions. To avoid overheating and dehydration in hot environments by reducing metabolic activity. Occurs primarily in response to heat or dry conditions. Helps animals conserve water and energy when resources are scarce. b. Example: Snails, Lemure Constraint in terrestrial is availability of water ❖ Dry/Arid Environments (Plants) Absorb and store large amounts of water from summer rains Soil moisture influences the extent of root development Plants in arid areas often develop deep or extensive root systems to access water deep underground. Cacti and other succulents store water in their thick, fleshy tissues for prolonged drought periods. ❖ Invertebrates Absorb water from air (Water vapor absorption) to thrive in environments with very little liquid water Example: Bristly millipedes have the ability to absorb moisture directly from humid air. Jungle Ways ❖ Rely on water flow in trenches in desert or coastal environments. Example: Trench-digging beetle in the Namib Desert digs trenches to collect moisture from the air and fog. ❖ Water flows in the body Example: Basking beetle allows moisture to condense on its body and channel it toward its mouthparts. ❖ Slow down, conserve, stay out of the sun Metabolic rates, By staying underground, To minimize water evaporation/loss Reduces water loss through evaporation ❖ Cicada Evaporative cooling system Has rich supply of water; Sweat Has host plant as source of water ❖ Survive only on metabolic water From breaking down food ❖ Camel Withstand long periods without water Humps made up of fats  ACQUIRING ENERGY AND NUTRIENTS AUTOTROPH Photoautotrophy Chemoautotrophy 01. Sunlight as source 01. Inorganic matter molecules 02. With Carbon a. Uses Nitrogen (N2) 02. Without Carbon HETEROTROPH Herbivory Carnivory 01. Coprophagy 01. Piscivore a. Feeds on poop or dung-eating a. Eats specific types of fish b. Cause: To further extract 02. Saprotrophs materials of rich organic 03. Insectivore matter that they could not 04. Hematophagy digest the first time. a. Feeds on blood c. Example: Beetles that form b. Example: Vampire bats to cow round poop; Rabbits eat poop or big mammal blood to digest it more and more. 05. Kleptoparasitism 02. Grazer (Ground level) a. Stealing of food that another 03. Browser (Above ground level) animal has caught, collected, 04. Frugivory (Fruits) or otherwise prepared, to 05. Folivory (Leaf) conserve energy. 06. Granivory (Seed) b. Example: Seagull 07. Nectarivory (Nectar) 06. Scavenging 08. Xylophagy (Wood) a. Feeds on the remains of 09. Palynivory (Pollen) animals. 10. Mucivory (Plant sap) b. Rely on finding carrion 11. Rhizophagy (Roots) (decaying flesh) or leftover kills from other predators. ★ Carnivory + Autotrophy ○ Cause: Due to the absence of sunlight and less nutrients in soil. ○ Example: Venus flytrap, Pitcher plant  SOCIAL INTERACTION Darwin: Mating environment could exert significant influence on the characteristics of organisms. ❖ He called it “Secondary Sexual Characteristics” Presented advantage during competition for mates in reproduction/mating. Indirectly used to reproduce organisms. Example: Presence of antlers in male deers Color of feathers in birds ❖ He coined the term “sexual selection” Results from differences in reproductive rates among individuals as a result of differences in their mating success. Sexual Selection 01. Intrasexual Competition a. Same sex competition b. Example: Mammals like elephant seals compete with each other and usually involve violence which may lead to death. 02. Intersexual Competition a. Opposite sex competition where females get to choose. b. Example: Pehen chooses peacock with vibrant and big feathers 03. Kin Selection a. “Family matters” An evolutionary force where individuals give help to relatives. b. Example: Meerkat exhibits “cooperative breeding” 1 dominant male and female will mate only Others will look out for each other c. Example: Pride of Lions Adult lioness nurse even non-related cubs to care for and protect, when lions become aggressive towards “weak” cubs Lions goal is to make lioness pregnant.  BEHAVIORAL PATTERNS 01. Epiphytic a. Organisms that grow on the surface of plants (usually trees) without harming them. Attached to higher structures like trees. Gain support and access to light and air without being rooted in the ground. b. Example: Orchids 02. Fossorial a. “Burrower” Adapted to digging and living underground. Provides protection from predators, harsh environmental conditions, and shelter. b. Example: Mole rats have big hands/claws 03. Troglophilic a. “Cave-dwelling” Live in caves but can also survive outside of them. Has less predators due to the dark environment. Less competition because not many organisms are adapted to caves. Usually has transparent bodies. Has vestigial eyes: minimally or non-functional eyes due to evolution; no longer rely on vision upon living in environments where sight is unnecessary Has other senses that work sharply and unique for caves. b. Example: Cave-dwelling fish are born with eyes but gradually loses them 04. Arboreal a. “Tree-dwelling” Live in trees or primarily use trees for movement and shelter. Provides safety from predators, access to food, and nesting sites. b. Example: Monkey has muscular limbs and tails used for swinging, Squirrel 05. Nocturnal a. “Active at night and rest during the day” Helps avoid daytime predators and competition. To conserve energy in cooler temperatures. b. Example: Owls, Bats used to be in competition with birds so they took advantage of night and developed unique functions for it 06. Nomadic a. “No permanent shelter” Move continuously from one place to another in search of resources. Ensures survival by following seasonal availability of food or shelter. For exploration of population b. Example: Lions explore in search of populations with better females to mate with, Migratory birds, Historical human tribes 07. Sessile a. “Immobile” Fixed in one place and do not move throughout their lives. Anchors the organism in a stable position to access nutrients, filter feed, or reproduce. Advantageous to aquatic animals b. Example: Corals, Barnacles, Sponges, Clams 08. Swarming a. “Big group of individuals” Behavior where animals gather in large numbers and move collectively. For protection from predators; For foraging or reproductive success Advantageous because they will scare off predators by appearing big. Terrestrial animals huddle for protection and warmth. b. Example: Sardines, Bees, Meerkat 09. Parasitic a. Live on or within another organism (the host) and benefit at the host's expense. Derive nutrients or shelter from the host, often weakening or harming it. b. Example: Mistletoe has haustoria (specialized roots) which penetrates the host’s tissues to absorb nutrients and water. 10. Symbiotic a. Live in close association with another species, benefiting both or one without harming the other. Mutual benefits like protection, nutrients, or shelter. b. Example: Mongoose gains food from parasites and warthog receives pest-control COMMUNICATION AND SENSES 01. Production of Ultrasound and Echolocation a. Use of high-frequency sounds to navigate and locate prey or obstacles. Helps in navigation and hunting in dark or murky environments. b. Example: Bats and Dolphins to navigate and find food 02. Acoustic Communications a. Communication through sound signals, often involving vocalizations or calls. Facilitates mating, territory defense, and social interactions. b. Example: Cicada to call mates, Wolf howl, Bird songs 03. Visual Communication a. Use of visual signals, including body language, colors, and displays to convey information or how they are seen by other organisms. Enhances social interactions, mate attraction, and warnings. b. Example: Bee-orchids attract bees for pollination, Frilled lizards have big scaly membranes around its neck to scare off predators 04. Chemical Communication a. Use of chemical signals (pheromones), or release substances Helps in mating, marking territory, attracting preys, and signaling danger. b. Example: Skunk releases unpleasant substances to scare off predators, Rafflesia has a foul scent to attract different types of pollinators like rats and flies 05. Tactile Sense a. Ability to sense other organisms within the vicinity. b. Communication through touch, often used in social bonding or signaling. c. Example: Sharks 06. Mimicry a. The resemblance of one organism to another, either living or inanimate to gain an advantage. Can provide protection from predators; facilitate predation. b. Example: Praying mantis mimicking a leaf, Pebble plants mimicking rocks, 07. Bioluminescence a. The production and emission of light through metabolic processes. Can attract mates, lure prey, or deter predators. b. Example: Firefly and the way they flicker light 08. Aposematism a. Warning coloration or signals that indicate toxicity or unpalatability to potential predators. Deters predators by signaling that the organism is harmful, venomous, or distasteful. b. Example: Bright colors of poison dart frogs, Monarch butterflies MORPHOLOGY 01. Camouflage a. An organism blends in with its environment. To avoid detection and risk of predation (for preys) Helps in predator evasion and enhances hunting success by ambushing prey (for predators) b. Example: Tiger blending with tall grass, octopus changing color and texture to match rocks or coral. 02. Sexual Dimorphism a. Two morphological features Distinct differences in size or appearance between males and females of the same species. Can enhance mating success, attract mates, or reflect different roles in reproductive behaviors. b. Example: Peacock (males with bright feathers vs. females), frogs (males typically smaller with vocal sacs). REPRODUCTIVE STRATEGIES 01. Precocial a. Newborn offspring are mobile and relatively independent at birth. b. To quickly escape from potential predators. c. Example: Ducks, Deer 02. Altricial a. Newborn offspring are immobile and helpless at birth. b. Requires parental care for survival and development. c. Example: Birds, Humans, Cats 03. Asexual Reproduction  a. Reproduction without the involvement of gametes. b. Allows reproduction in the absence of a mate. c. Example: Bacteria, Protists 04. Parthenogeny a. A form of asexual reproduction where female eggs develop into embryos without fertilization; virgin birth. b. Enables reproduction when mates are scarce. c. Example: Lizards The way animals give birth: 01. Oviparity a. Eggs are laid outside the mother's body. Nutrients provided by the egg yolk. Eggs are fertilized and develop outside. Offspring hatch from eggs laid in the environment. Lower energy investment for laying eggs. b. Eggs are vulnerable to predation. c. Often produce many eggs at once. d. Example: Chicken 02. Ovoviviparity a. Eggs develop inside the mother's body and hatch internally. Nutrients provided by the egg yolk; no placental connection. Eggs are fertilized and develop inside until hatching. Offspring are born live, often immediately after hatching. Moderate energy investment as the mother carries the eggs b. Eggs are protected inside the mother's body. c. Generally fewer offspring than oviparous species. d. Example: Boa constrictors, Great white shark 03. Viviparity a. Embryos develop inside the mother's body and are nourished directly. Nutrients provided through the placenta from the mother. Embryos develop and grow directly inside the mother. Offspring are born alive after a gestation period. Higher energy investment as the mother supports the developing embryo. b. Young are protected and nourished within the mother. c. Usually fewer offspring due to energy investment in development d. Example: Humans, Cats, Dogs 04. Hermaphroditism a. Has female and male sex organs Homogamy (Homogamous) Has testes and ovary all through its lifetime Example: Earthworm Dichogamy (Dichogamous) Has one sex organ on one part of their life Example: Clown fish Male at birth but in the absence of female, it can become female. Based on reproductive rates: 01. Semelparity a. Reproduction in which an organism reproduces once in its lifetime and then dies. b. Allocates all energy and nutrients to a single reproductive event, maximizing offspring production at once. c. Example: Salmon  02. Iteroparity a. Reproduction in which an organism can produce multiple offspring over its lifetime. b. Allows for repeated chances of reproduction, increasing overall reproductive success and survival of the species. c. Example: Humans, Mammals, Birds Based on the number of partners: 01. Monogamy (Monogamous) a. A mating system where an individual has only one partner for life or for a breeding season. b. Promotes strong pair bonds, cooperative parenting, and increases the likelihood of offspring survival. c. Example: Penguins, Humans, Swans 02. Polygamy (Polygamous) a. A mating system in which an individual has multiple mates. b. Increases reproductive growth and potential reproductive success through multiple partnerships. c. Example: Deer, Elephants Polygyny (Female): A type of polygamy where one male mates with multiple females. Allows males to maximize reproductive output by mating with multiple females. Example: Lions, Gorillas Polyandry (Male): A type of polygamy where one female mates with multiple males. Can enhance genetic diversity and ensure that offspring are cared for by multiple males. Example: Bees