Animal Behavior PDF

Animal Behavior and Learning 8/27/24, 12:49 PM Platform | Study Fetch Types of Animal Behavior (00:47 - 00:59) Innate Animal Behaviors: Instinct Reflexes Fixed Action Patterns Imprinting Mnemonic: FURI (Fur) I...

Animal Behavior and Learning 8/27/24, 12:49 PM Platform | Study Fetch Types of Animal Behavior (00:47 - 00:59) Innate Animal Behaviors: Instinct Reflexes Fixed Action Patterns Imprinting Mnemonic: FURI (Fur) Instincts (01:11 - 01:36) Circadian rhythm - internal clock that synchronizes with light/dark cycles Controlled by the brain, influenced by light hitting the retinas Reflexes (01:36 - 02:10) Automatic, involuntary responses to stimuli Examples: Switching to non-slipping leg when slipping Patella reflex (knee-jerk) Mediated by simple neural pathways Fixed Action Patterns (02:10 - 02:31) Predictable, species-specific behaviors triggered by a "sign stimulus" Increase fitness over generations Example: Goose retrieving egg outside nest Imprinting (02:31 - 02:44) Rapid learning of a specific stimulus, often in a critical period Allows young animals to recognize and bond with parents/caregivers Animal Communication https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce030af375447b4024d1dc/document?newNote=true&go=note 1/6  (02:44 - 03:00) 8/27/24, 12:49 PM Platform | Study Fetch Animals use various methods to communicate: Visual (body language, displays) Auditory (vocalizations) Chemical (pheromones) Tactile (touch) Social Behavior and Mating (03:00 - 03:20) Social behaviors include: Cooperation Competition Dominance hierarchies Courtship and mating rituals Animal Learning and Conditioning Critical Period Learning (00:02:56 - 00:03:10) Animals learn behaviors during a critical period, like goslings/ducklings following their mother These are behaviors learned by observing their immediate parental figure Types of Learning (00:03:10 - 00:03:23) There are multiple types of learning: Associative learning Classical conditioning Operant conditioning Observational learning Classical Conditioning (00:03:23 - 00:04:16) Also known as Pavlovian conditioning Involves an unconditioned stimulus (like food) that elicits an unconditioned response (like salivation) A neutral stimulus (like a whistle) is paired with the unconditioned stimulus https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce030af375447b4024d1dc/document?newNote=true&go=note 2/6  After repeated pairings, the neutral stimulus becomes a conditioned stimulus that elicits the 8/27/24, 12:49 PM Platform | Study Fetch conditioned response (salivation) Operant Conditioning (00:04:16 - 00:04:49) A way to encourage or discourage behaviors Reinforcement increases a behavior Positive reinforcement adds a pleasant stimulus Negative reinforcement removes an unpleasant stimulus Punishment decreases a behavior Positive punishment adds an unpleasant stimulus Negative punishment removes a pleasant stimulus Examples of Operant Conditioning (00:04:49 - 00:05:34) Positive reinforcement: Giving a child a lollipop for cleaning their room Positive punishment: Making a child mop the floor as punishment for making a mess Negative reinforcement: Removing a chore for a child who did their homework Reinforcement and Punishment (00:05:55 - 00:06:07) Positive reinforcement: Adding a pleasant stimulus to increase a behavior Negative reinforcement: Removing an unpleasant stimulus to increase a behavior Positive punishment: Adding an unpleasant stimulus to decrease a behavior Negative punishment: Removing a pleasant stimulus to decrease a behavior Example: Johnny didn't clean his room, so he is not allowed to go to sports practice (negative punishment) (00:06:07 - 00:06:22) Reinforcement increases a behavior, punishment decreases a behavior Positive is adding a stimulus, negative is removing a stimulus It's important to understand the differences between these concepts (00:06:22 - 00:06:43) Associative learning: Associating one thing with another Sensitization: Increased stimulus leads to increased behavioral response Habituation: Repeated stimulus leads to decreased response (00:06:43 - 00:07:00) Habituation example: Fire alarm going off frequently leads to not reacting to it anymore The person becomes habituated to the stimulus (00:07:00 - 00:07:12) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce030af375447b4024d1dc/document?newNote=true&go=note 3/6  Observational learning: Learning by observing others 8/27/24, 12:49 PM Platform | Study Fetch Example: Child observing parent folding laundry and copying the behavior (00:07:12 - 00:07:28) Insight: Ability to solve a problem using previous experiences Improves as animals become more advanced in the phylogenetic tree (00:07:28 - 00:07:46) Kinesis: Change in rate of random movement in response to a stimulus Example: Bug moving randomly until it finds a moist environment (00:07:46 - 00:08:10) Taxis: Change in direction towards or away from a stimulus Example: Bug moving towards a moist environment Animal Behavior and Communication Kinesis vs. Taxis (00:08:35 - 00:09:00) Kinesis is a change in the rate of movement in a random direction Example: Gas particles moving randomly and bouncing around Taxis is a change of movement in a specific direction Example: A car driving in a certain direction Migration (00:09:00 - 00:09:10) Migration is a seasonal, long-distance movement Example: Geese or other migratory birds moving from one location to another based on changing seasons Animal Communication (00:09:10 - 00:10:21) There are four main forms of animal communication: 1. Visual: Courtship and mating rituals, dances 2. Auditory: Vocalizations like wolf howling to signal location and group cohesion 3. Tactile: Animals bonding through touch, like elephants touching trunks 4. Chemical: Pheromones signaling readiness to mate, danger, etc. Mnemonic: FACT (Visual, Auditory, Chemical, Tactile) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce030af375447b4024d1dc/document?newNote=true&go=note 4/6  Social Behavior and Mating 8/27/24, 12:49 PM Platform | Study Fetch (00:10:21 - 00:11:09) Cooperation: Animals working together to achieve a goal Agonistic Behavior: Threats or aggression to make another animal submit Aggression: Behavior intended to harm both animals involved Dominance Hierarchy: A social hierarchy with a defined order "Any animals can cooperate, and agonistic behavior is threats or aggression. This is ways in which an animal would get another animal to submit to them." Term Definition Cooperation Animals working together to achieve a goal Agonistic Behavior Threats or aggression to make another animal submit Aggression Behavior intended to harm both animals involved Dominance Hierarchy A social hierarchy with a defined order (Video timestamps in parentheses) Animal Behavior Territoriality (00:11:09 - 00:11:22) Territoriality is an animal's protecting a given territory This could be done with pheromones Even dogs will urinate to mark their scent on a specific territory and claim it as their own This is where the animal hunts, stays, and breeds Altruistic Behaviors (00:11:22 - 00:11:37) Many animals use altruistic behaviors, which involve sacrificing for relatives This is an adaptive type of behavior that would lead to improved survival of the species Inclusive Fitness https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce030af375447b4024d1dc/document?newNote=true&go=note 5/6  (00:12:04 - 00:12:17) 8/27/24, 12:49 PM Platform | Study Fetch Inclusive fitness is an animal's direct fitness (number of genes it can pass down on its own) plus its indirect fitness (number of genes its relatives can pass down) Kin selection is natural selection in favor of behavior by individuals that may decrease their chance of survival, but increase that of their kin Reciprocal Altruism (00:12:27 - 00:12:42) Reciprocal altruism is the sacrifice for an unrelated animal of the same species This benefits the species as a whole, rather than just the individual's kin Sexual Selection (00:12:54 - 00:13:20) Sexual selection is the difference between males and females in mating behaviors Male competition: Stronger males have more mating opportunities (e.g. deer fighting for mates) Female choice: Females select mates with desirable characteristics, increasing the frequency of those traits Sexual Dimorphism (00:13:20 - 00:13:38) Sexual dimorphism is the differences between males and females, physically and in color patterning, build, etc. Mating Strategies (00:13:38 - 00:13:50) Monogamy: Having only one partner at a time Polygamy: Having multiple mating partners Semelparity: Mating once during a lifetime Iteroparity: Mating many times during a lifetime https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce030af375447b4024d1dc/document?newNote=true&go=note 6/6  Ecology and Evolution 8/27/24, 1:50 PM Platform | Study Fetch Environmental Ecology (00:00:39 - 00:01:55) Key Terms: Species: A group of organisms that can interbreed to produce viable, fertile offspring Habitat: The place where an organism lives Population: A group of organisms of the same species in a given location Ecological Community: All the populations of different species in a given area Ecosystem: The ecological community and its abiotic factors Abiotic Factors: The non-living elements of an environment (e.g., water, soil) Biotic Factors: The living elements of an environment Biosphere: All the ecosystems on Earth Ecological Factors: Density-Dependent Factors: Factors that depend on population density (e.g., disease, resource competition) Density-Independent Factors: Factors that are independent of population density (e.g., weather, climate) Niche: Realized Niche: The environment where an organism actually lives Fundamental Niche: The range of environmental conditions where an organism can survive Competitive Exclusion Principle: Two species cannot occupy the same niche and maintain population levels; they will compete for limited resources Diagram Example: Shows different bird species foraging at different heights in a forest, demonstrating how they occupy different niches to avoid competition for resources. Biological Interactions (00:04:01 - 00:04:58) Types of Competition: Exploitation Competition: Competition for a common, depleted resource Indirect Competition: Competition for a common, depleted resource Interspecies Competition: Competition between members of the same species for resources Apparent Competition: Competition between two species mediated by a shared predator Types of Biological Interactions (00:05:10 - 00:05:24) Mnemonic for types of competition: Apparent, Exploitation, Interspecies https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 1/7  Symbiosis is an important type of biological interaction to understand 8/27/24, 1:50 PM Platform | Study Fetch Symbiotic Relationships (00:05:24 - 00:05:41) Mutualism: Both species benefit Example: Clownfish and sea anemone Commensalism: One species benefits, the other is unaffected Parasitism: One species benefits, the other is harmed Example: Mosquito or tick Ecosystem Ecology Terminology Food Chains and Food Webs (00:05:54 - 00:06:07) Food Chain: Linear depiction of food interactions Food Web: Interconnected food chains Trophic Levels (00:06:07 - 00:06:37) Autotrophs: Produce their own energy, typically from the sun Heterotrophs: Consume organic compounds for energy Predation: When a predator consumes prey Biomass: Total mass of living organisms in an area Producers, Consumers, and Predators (00:06:37 - 00:07:25) Producers: Primary consumers (e.g., herbivores like cows) Secondary Consumers: Prey on primary consumers Tertiary Consumers: Prey on secondary consumers Apex Predator: Top predator in a given area Energy Flow in Ecosystems (00:07:25 - 00:08:50) Only 10% of energy is converted to organic tissue at each trophic level Energy is lost as heat, waste, and decomposition This limits the biomass at higher trophic levels Decomposers and Scavengers (00:09:04 - 00:09:38) Decomposers: Microorganisms and invertebrates that break down organic material at the molecular level e.g., fungi, bacteria Scavengers: Animals that feed on dead or decaying matter Also called detritivores Scavengers break down large organic material, while decomposers break it down at the molecular level (00:09:38 - 00:10:01) Decomposers are essential for the integrity of the environment Without decomposers, we would be surrounded by undecomposed organic material https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 2/7  Decomposition and Nutrient Cycling 8/27/24, 1:50 PM Platform | Study Fetch (00:10:01 - 00:10:12) During autumn, leaves fall to the ground and accumulate as debris In the spring, the snow melts and the debris is left behind (00:10:12 - 00:10:24) Decomposers break down the fallen leaves during the winter This turns the leaves back into fresh soil Population Ecology (00:10:24 - 00:10:38)Biotic Potential The ability of a species to have the highest possible birth rate and lowest possible death rate This is the maximum population size a species can achieve (00:10:38 - 00:10:50)Carrying Capacity The maximum population size that an environment can sustainably support This is the limit to the biotic potential of a species (00:10:50 - 00:11:03)Population Growth The population will initially grow exponentially, following the biotic potential But it will then level off at the environmental carrying capacity (00:11:03 - 00:11:15) The population growth will be a sinusoidal curve It will reach a threshold based on the carrying capacity (00:11:15 - 00:11:34) The carrying capacity is limited by resources like food, water, and habitat As resources are depleted, the death rate will increase, limiting the population (00:11:34 - 00:11:54) Even if a species can produce many offspring, the population will stabilize at the carrying capacity Excess deaths from lack of resources will balance the high birth rate r/K Selection Theory (00:11:54 - 00:12:07) Different species employ different tactics to produce offspring r-selected species focus on quantity, K-selected species focus on quality (00:12:07 - 00:12:22)K-selected Species Have long gestation periods to produce a few large, robust offspring The offspring take a long time to mature but have a low mortality rate (00:12:22 - 00:12:35)r-selected Species Produce many small offspring that mature quickly Many of the offspring do not survive, but some will reach adulthood https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 3/7 8/27/24, 1:50 PM Platform | Study Fetch (00:12:35 - 00:12:52) r-selected species have a "quantity over quality" approach K-selected species have a "quality over quantity" approach (00:12:52 - 00:13:06)Survival Curves Type I: High percentage of individuals reach maximum lifespan Type II: Constant mortality rate over lifespan Type III: Very few individuals reach maximum lifespan (00:13:06 - 00:13:31) K-selected species have a Type I survival curve with many survivors r-selected species have a Type III curve with few survivors reaching maximum lifespan (00:13:31 - 00:13:54) Catastrophic events are more detrimental to K-selected species, as they have invested heavily in few offspring r-selected species can better withstand losses since they produce many offspring Ecological Succession (00:14:28 - 00:14:42)Ecological Succession The process by which a community develops and changes over time The first species to inhabit an area are called pioneer species (00:14:42 - 00:15:04) There are typically not totally "unfounded" areas, as some life will exist even in newly formed environments The pioneer species begin the process of ecological succession Primary Succession and Secondary Succession (00:15:04 - 00:15:18) Most areas on our planet have had life at some point, even if they are currently uninhabitable like Antarctica or the Arctic These areas can change over time and become re-inhabited Primary Succession (00:15:18 - 00:16:19) Occurs after a large disturbance in an area that has previously not supported life For example, if Antarctica suddenly became very warm Starts with bare rocks and pioneer species Progresses through different stages of succession (lichen, small plants, grasses, shrubs, trees) until it reaches a climax community Climax community is a steady state where ecological succession has achieved a mature, stable ecosystem Secondary Succession (00:16:19 - 00:17:19) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 4/7  Occurs after a smaller disturbance in an area that has recently supported life 8/27/24, 1:50 PM Platform | Study Fetch For example, a large forest fire Still has a pioneer species and intermediate species, but the process is more rapid Often has some surviving seeds or species that can reestablish more quickly since there is still soil present Keystone Species and Predators (00:17:19 - 00:18:33) Keystone species and keystone predators are critical to maintaining the balance of an ecosystem Example: Sharks are keystone predators that feed on cownose rays If sharks were eliminated, the cownose ray population would explode and decimate other species like bivalves and arthropods This can cause a cascading disruption throughout the entire ecosystem Similar effects were seen when wolf populations were disrupted in the northeastern US, leading to deer overpopulation and coyote invasions Biomes (00:19:07 - 00:19:39) Biomes are areas of land or water defined by their biotic factors, rainfall, and temperature Key terrestrial biomes include: Tropical rainforests Savannas Temperate grasslands Deciduous forests Chaparrals Deserts Taiga Tundra Polar regions Each biome has its own specific temperature and rainfall patterns that define its unique ecosystem Biomes and Ecosystems Tropical Rainforests (00:19:39 - 00:19:57) Unique tropical rainforests have heavy rainfall Very hot and high humidity, allowing for a great diversity of plant species Diverse plant species provide a diverse structure for animals to live in, resulting in a diverse selection of animals Savannas https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 5/7  (00:19:57 - 00:20:24) 8/27/24, 1:50 PM Platform | Study Fetch Hot with very little rainfall Dominated by grasses and some trees Suitable for ungulates (hoofed animals) like giraffes that can move throughout the savanna, graze on the grasses and trees, and find shade Adapted to low amounts of water and rainfall Temperate Grasslands (00:20:24 - 00:20:39) Cool winters, hot summers, and seasonal rain Dominated by grasses and shrubs Many grazing animals thrive in this environment Temperate Deciduous Forests (00:20:39 - 00:21:05) Warm summers, cold winters, and moderate rain Dominated by hardwood trees that shed their leaves in the fall Home to many smaller mammals like birds, rodents, squirrels, porcupines, weasels, and deer Chaparral (00:21:05 - 00:21:32) Hot and dry summers, mild winters Dominated by trees, shrubs, and cacti Home to animals like foxes, deer, and jackrabbits Deserts (00:21:32 - 00:21:57) Hot days, cold nights, very little rain Mainly home to cacti, reptiles, arachnids, and coyotes Hard to support a large biomass due to the harsh conditions Taiga (Coniferous Forests) (00:21:57 - 00:22:13) Cold winters with snowfall, warm rainy summers Dominated by coniferous trees Home to larger mammalian species like bears, otters, and wolves, as well as smaller mammals Tundra (00:22:13 - 00:22:26) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 6/7  Cold with little precipitation 8/27/24, 1:50 PM Platform | Study Fetch Dominated by mosses and shrubs Home to bears, wolves, caribou, and reindeer Polar Regions (00:22:39 - 00:22:57) Cold, snowy weather, mostly ice, very little plant life Home to penguins and polar bears Aquatic Biomes (00:23:14 - 00:23:26) Saltwater biome is the largest on Earth Freshwater biome has less than 0.1% salt content Aquatic Ecosystem Zones (00:23:26 - 00:23:52) Euphotic Zone: Closest to the surface, with good light penetration Littoral Zone: Part of the euphotic zone where sunlight reaches the bottom Dysphotic Zone: Semi-radiated, not enough light for plants to survive Aphotic Zone: No light, few if any species can survive (deep ocean) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 7/7  Evidence and Theories of Evolution 8/27/24, 2:14 PM Platform | Study Fetch (00:00:46 - 00:00:59)The evidence for evolution includes: Fossil record Biogeography Embryology Comparative Anatomy Biochemical methods Fossil Record (00:01:10 - 00:01:28) Fossils can be actual remains or impressions/traces (e.g., footprints, scat) Petrification is the process where organic matter becomes stone over time Biogeography (00:01:28 - 00:01:57) The geographical distribution of plants and animals Pangaea was a large supercontinent that broke apart over time, allowing organisms to evolve in isolation on the new landmasses Embryology (00:02:08 - 00:02:19) The study of embryos and their development Similarities in embryological development across related organisms support common ancestry Comparative Anatomy (00:02:32 - 00:03:13) Anatomical similarities between organisms indicate a shared common ancestor Homologous structures are similar in structure but may have different functions Analogous structures have similar functions but did not evolve from a common ancestor Vestigial structures are remnants of structures that no longer serve a purpose Biochemical Evidence (00:03:59 - 00:04:21) Similarities in biochemical pathways and genome structure between organisms support evolutionary relationships Chimpanzees and humans share a high degree of genetic similarity, indicating a close evolutionary relationship https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 1/8  Mnemonic for Evidence of Evolution:Emily Compares Biochemistry, Grades, Biography Reports, 8/27/24, 2:14 PM Platform | Study Fetch and Fossils Important Figures and Theories (00:04:57 - 00:05:26)Baron George Cuvier Founder of paleontology Proposed the theory of catastrophes, where sudden environmental changes led to mass extinctions Jean Baptiste Lamarck Proposed the theory of use and disuse, where increased use of a body part leads to its growth and development, while unused parts atrophy (00:05:26 - 00:05:44) Lamarck's theory of use and disuse suggested that changes acquired during an organism's lifetime could be passed on to offspring, which is now known to be incorrect. (00:05:44 - 00:05:56) Lamarck's theory was an early attempt to explain evolution, but it was later superseded by Charles Darwin's theory of natural selection. Lamarck's Theory of Acquired Traits (00:05:56 - 00:06:10) Lamarck proposed the theory of acquired traits This theory states that if an organism acquires a trait during its lifetime, that trait can be passed on to its offspring This idea was disproven by Charles Darwin Epigenetics and Heritable Traits (00:06:10 - 00:06:29) There is some evidence that certain epigenetic factors can allow for adaptation and changes during an organism's lifetime These changes could potentially be heritable However, this is not the main mechanism by which evolution takes place Charles Darwin and Natural Selection (00:06:40 - 00:06:53) Charles Darwin proposed the theory of natural selection This theory states that organisms better adapted to their environment will survive and produce more offspring These offspring will then inherit the same beneficial traits as their parents https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 2/8  Terminology of Natural Selection 8/27/24, 2:14 PM Platform | Study Fetch (00:07:04 - 00:07:28) Natural selection is a gradual, non-random process where alleles become more or less common due to an organism's interactions with the environment Survival of the fittest refers to reproductive success, not just longevity Requirements for natural selection: Competition for scarce resources Variation in fitness among organisms Heritability of traits Organisms produce more offspring than can normally survive Types of Natural Selection (00:08:34 - 00:10:37) Stabilizing Selection Maintains a non-extreme, mainstream trait Example: Robins typically laying 4 eggs Extreme traits are selected against Directional Selection Shifts the population towards one extreme trait Example: Light-colored moths being selected for on a light background Disruptive Selection Selects for extreme traits, diversifying the population Example: Gray and Himalayan rabbits being selected for in different environments Table: Comparison of Natural Selection Types Type Description Example Stabilizing Maintains non-extreme, Robins laying 4 eggs mainstream traits Directional Shifts population towards one Light-colored moths on light extreme trait background Disruptive Selects for extreme traits, Gray and Himalayan rabbits diversifying population https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 3/8  Types of Natural Selection 8/27/24, 2:14 PM Platform | Study Fetch (00:10:52 - 00:11:06) Stabilizing Selection: A bell curve where the mainstream is favored, forcing everything to the mean. This gives a stable life. (00:11:06 - 00:11:17) Directional Selection: One extreme is favored, going in one direction. Disruptive Selection: The graph looks like a mountain, with two peaks split by disruption. Microevolution vs. Macroevolution (00:11:17 - 00:11:37)Microevolution: Changes in a gene pool, the allele frequency of a single population Genes will increase in frequency as they suit the environment Macroevolution: Sources of genetic variation Speciation (00:11:37 - 00:11:54) Example of microevolution: In a population of multicolored beetles, green beetles may have an advantage if there is a lot of plant life, so the population will shift towards being more green. Then, if the environment changes (e.g., a fire, land becomes dry), the beetles may shift towards being more brown to better suit the new environment. (00:12:04 - 00:12:18) The Hardy-Weinberg formula can be used to determine allele frequencies within a population, assuming no changes in gene frequency. P + Q = 1, where P is the frequency of the dominant allele and Q is the frequency of the recessive allele. (00:12:18 - 00:12:30) The Hardy-Weinberg formula also states that P^2 + 2PQ + Q^2 = 1, where P^2 is the frequency of homozygous dominant individuals, Q^2 is the frequency of homozygous recessive individuals, and 2PQ is the frequency of heterozygous individuals. (00:12:30 - 00:12:54) Example: If the frequency of the dominant allele (P) is 0.5, then the frequency of the recessive allele (Q) is also 0.5. The formula can be used to calculate the frequencies of different genotypes within a population. (00:12:54 - 00:13:24) The Hardy-Weinberg equilibrium requires certain assumptions to hold true: No selection No mutation No migration Large population Random mating https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 4/8 8/27/24, 2:14 PM Platform | Study Fetch (00:13:24 - 00:13:56) Example: In a garden of 100 pea plants, 86 have yellow peas and 16 have green peas (homozygous recessive). Using the Hardy-Weinberg formula, we can calculate: Q^2 = 0.16, so Q = 0.4 P = 1 - Q = 0.6 Frequency of homozygous dominant plants = P^2 = 0.36 (36 plants) Frequency of heterozygous plants = 2PQ = 0.48 (48 plants) (00:13:56 - 00:15:19) The Hardy-Weinberg equilibrium assumptions must be met for the formula to be applicable: No selection No mutation No migration Large population Random mating (00:15:19 - 00:15:46) Mnemonic for the Hardy-Weinberg equilibrium requirements: Large population Random mating Minimizing the effects of genetic drift No mutations Minimizing the effects of natural selection Allele Frequencies and Genetic Drift (00:15:57 - 00:16:07) Allele frequencies are stable and not impacted when a population is isolated with no migration Genetic drift is a factor that can cause evolution in an isolated population Mechanisms of Evolution (00:16:07 - 00:16:20) Evolution can occur through: Mutations Bottleneck effect Founder effect Non-random mating Natural selection Gene flow Bottleneck Effect vs. Founder Effect https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 5/8 8/27/24, 2:14 PM Platform | Study Fetch (00:16:20 - 00:16:49) Bottleneck Effect: A population is drastically reduced, and only a few alleles can survive Analogous to a forest fire where most of the population dies off Founder Effect: A segment of a population breaks off and forms a new population The new population may lack the same genetic diversity as the original Non-Random Mating (00:16:49 - 00:17:16) Outbreeding: Breeding with non-familiar members Inbreeding: Breeding with relatives There can be selection for non-random mating based on accessibility and desirable characteristics Natural Selection and Gene Flow (00:17:34 - 00:17:58) Natural selection favors traits based on fitness Gene flow is the movement of alleles between populations Gene flow can introduce new changes and alter the dynamics within a population Macroevolution (00:18:14 - 00:18:25) Macroevolution is major evolutionary change over long periods of time Examples include dinosaurs evolving into birds or fish evolving into mammals Pre-Zygotic Isolation Mechanisms (00:18:25 - 00:19:06) Gametic Isolation: Eggs and sperm cannot fuse Mechanical Isolation: Physical barriers prevent mating Habitat Isolation: Populations live in different habitats Temporal Isolation: Populations breed at different times Behavioral Isolation: Populations have different mating behaviors Post-Zygotic Isolation Mechanisms (00:19:21 - 00:19:43) Hybrid Mortality: Hybrid zygote is not viable Hybrid Sterility: Hybrid cannot reproduce Hybrid F2 Breakdown: Hybrid offspring have decreased fitness https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 6/8  Sources of Genetic Variation 8/27/24, 2:14 PM Platform | Study Fetch (00:20:06 - 00:21:17) Mutation: Random changes in the genetic code Sexual Reproduction: Crossing over and independent assortment during meiosis Balanced Polymorphism: Heterozygote advantage, such as sickle-cell trait providing resistance to malaria Genetic Variation and Speciation Minority Advantage and Hybrid Advantage (00:21:36 - 00:21:54) Minority Advantage: A rare phenotype is favored over a common phenotype Hybrid Advantage: Breeding two different strains of organisms produces an organism that is better adapted to its environment Neutral Variations (00:21:54 - 00:22:07) Variations that neither benefit nor harm an organism Many different polymorphisms present in a cross human species that have no discernible, positive or negative effect Polymorphisms and Polyploid (00:22:07 - 00:22:32) Some polymorphisms can be loosely associated with different disease states Polyploid: Another source of genetic variation, typically very deleterious but can occur Diploid: The dominant allele can mask the effect of recessive alleles, allowing them to drift through a population Sources of Genetic Variation (00:22:32 - 00:23:09) Mutation: A source of genetic variation Balanced Polymorphisms: Maintain genetic variation in a population Polyploid: Increased number of chromosome pairs Sexual Reproduction: Mixes genetic material, creating new combinations Speciation https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 7/8  (00:23:09 - 00:23:38) 8/27/24, 2:14 PM Platform | Study Fetch Speciation: Species formation from a single ancestral species Allopatric Speciation: Occurs due to geographical barriers, leading to adaptive radiation Patterns of Evolution (00:23:38 - 00:24:25) Divergent Evolution: Initial species branches and splits off Convergent Evolution: Two separate species become more similar over time Parallel Evolution: Two separate species change individually on their own Co-evolution: Two species impart selective pressures on each other Mimicry (00:24:25 - 00:25:36) Batesian Mimicry: Harmless animals mimic the coloring of a harmful animal Müllerian Mimicry: Different poisonous species resemble each other Phylogenetic Trees (00:25:52 - 00:26:19) Clade: A cluster of species in a phylogenetic tree Homoplasy: Convergent evolution, where two clades develop similar characteristics Parsimony: Choosing the simplest scientific explanation that fits the evidence https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce1750d56e584fb7692bcb/document?go=note 8/8 8/27/24, 2:16 PM Platform | Study Fetch Reproduction and Developmental Biology Asexual Reproduction (00:00:37 - 00:01:29) Binary Fission Process by which a prokaryotic cell divides in half The cell replicates its DNA and then a septum is created to divide the cell into two daughter cells Budding Outgrowth that forms on organisms like hydra and yeast A smaller version of the organism forms and then breaks off to become an independent organism Regeneration Organism can be fragmented into multiple pieces, and each piece will form a new adult organism Parthenogenesis Embryo develops from an unfertilized egg in a sexually reproducing species Example: Honey bees Human Reproduction (00:01:29 - 00:03:40) Male Reproductive System Spermatogenesis Spermatogonia are the stem cells that produce sperm Spermatids are the partially differentiated sperm cells Sperm Structure Head contains the nucleus and acrosome (enzymes to penetrate egg) Midpiece contains mitochondria to power the tail/flagella Tail/Flagella provides motility to reach the egg Reproductive Anatomy Seminiferous tubules are the site of spermatogenesis Epididymis stores sperm Vas deferens transports sperm Ejaculatory ducts release sperm during ejaculation Urethra and penis allow sperm to exit the body Accessory Glands Seminal vesicles secrete fructose Prostate gland increases alkalinity Bulbourethral glands secrete mucus These fluids help protect and nourish the sperm https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 1/8 8/27/24, 2:16 PM Platform | Study Fetch Hormonal Regulation FSH from pituitary stimulates Sertoli cells to facilitate spermatogenesis LH from pituitary stimulates Leydig cells to produce testosterone Female Reproductive System Oogenesis Oogonia are the stem cells that produce oocytes Primary oocytes undergo meiosis to form secondary oocytes and polar bodies Ovarian Cycle Follicle development is stimulated by FSH Ovulation is triggered by a surge of LH Corpus luteum produces progesterone to prepare the uterus Uterine Cycle Menstruation occurs when the uterine lining is shed Proliferative phase rebuilds the uterine lining Secretory phase prepares the lining for implantation Fertilization and Embryonic Development Sperm must penetrate the egg's acrosome and zona pellucida Zygote undergoes cleavage divisions to form a blastocyst Blastocyst implants in the uterine lining and develops into an embryo Embryology (00:03:40 - 00:04:30) Germ Layers Ectoderm forms the nervous system and epidermis Mesoderm forms muscles, bones, circulatory system Endoderm forms the digestive and respiratory systems Organogenesis Development of the major organ systems from the germ layers Includes formation of the heart, lungs, brain, and other vital organs Fetal Development Placenta and umbilical cord provide nutrients and oxygen to the fetus Fetus undergoes dramatic growth and differentiation over 9 months Birth occurs when the fetus is ready to survive outside the uterus The Reproductive System The Male Reproductive System https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 2/8 8/27/24, 2:16 PM Platform | Study Fetch (00:03:40 - 00:03:51) The hypothalamus releases GnRH, which stimulates the anterior pituitary to release FSH and LH Testosterone from Leydig cells in the testes will: Inhibit the anterior pituitary and hypothalamus via negative feedback Stimulate the Sertoli cells The Female Reproductive System (00:03:51 - 00:04:03) The ovaries produce ova (eggs) The fallopian tubes are where the egg travels to reach the uterus (00:04:03 - 00:04:14) Ectopic pregnancy occurs when the embryo develops in the fallopian tube instead of the uterus The uterus is where the egg develops into an embryo The uterus has 3 layers: perimetrium, myometrium, and endometrium The endometrium is the layer that is shed during menstruation (00:04:14 - 00:04:28) The cervix is the entrance to the uterus from the vagina (00:04:28 - 00:04:39) Oogenesis produces 1 mature egg and several polar bodies, unlike spermatogenesis which produces 4 viable sperm (00:04:39 - 00:04:51) FSH stimulates follicle development in the ovaries LH stimulates ovulation of the egg Estrogen and progesterone regulate the menstrual cycle and secondary sex characteristics (00:04:51 - 00:05:04) Diagram of the menstrual cycle: Phase Hormone Levels Menstrual Flow Estrogen and progesterone low, FSH and LH somewhat higher but LH low Proliferative FSH and LH increase, estradiol increases Secretory Progesterone surges, then drops off (00:05:04 - 00:05:24) If pregnancy occurs, progesterone is maintained by the embryo's production of human chorionic gonadotropin (hCG) If no pregnancy, progesterone drops, signaling shedding of the endometrial lining (menstruation) (00:05:24 - 00:05:42) Hormone feedback loops in females: https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 3/8 8/27/24, 2:16 PM Platform | Study Fetch Hypothalamus releases GnRH Anterior pituitary releases FSH and LH Ovarian hormones (estradiol, progesterone) provide negative feedback to the hypothalamus and pituitary (00:05:42 - 00:07:03) Inhibin from Sertoli cells and testosterone from Leydig cells provide negative feedback to the hypothalamus and pituitary, regulating FSH and LH levels Fertilization and Early Embryonic Development Fertilization Events (00:07:03 - 00:07:25) Capacitation: Destabilizes the sperm's plasma membrane and increases its permeability to calcium Prepares the sperm to penetrate the egg Acrosome Reaction: Contact between the sperm and egg initiates the acrosome reaction The acrosome membrane fuses with the sperm head membrane, releasing enzymes that break down the zona pellucida (coating of the egg) Polyspermy Block: Prevents more than one sperm from fertilizing an egg Fast block: Depolarization of the egg's membrane helps repel sperm Slow block: Calcium ions released inside the egg's plasma membrane stimulate the cortical reaction Meiosis II: The fertilized egg completes meiosis II, releasing the second polar body Stages of Embryonic Development (00:09:13 - 00:10:26) Day 1: Fertilization Fertilization occurs, creating the zygote Day 2-3: Cleavage The zygote undergoes cell division, forming a compact mass of cells Day 4: Differentiation The cells differentiate into the inner cell mass and the trophoblast The blastocyst cavity forms https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 4/8 8/27/24, 2:16 PM Platform | Study Fetch Day 5: Implantation The blastocyst implants in the uterine epithelium The trophoblast cells begin to form the placenta Day 12: Bilaminar Disc The mesoderm forms and spreads The amniotic sac begins to enlarge Day 23: Amnion and Umbilical Cord The amniotic sac, chorion, and umbilical cord begin to form and function Monozygotic Twins Occur when a single fertilized egg divides into two separate embryos Can have different chorion and amnion configurations depending on the timing of the division Anterior Pituitary Hormones (00:07:03) LH (Luteinizing Hormone) is released from the anterior pituitary Fertilization and Early Embryonic Development Monozygotic vs. Dizygotic Twins (00:10:57 - 00:11:26) Monozygotic (identical) twins: Derived from the same embryonic origin Genetically identical Dizygotic (fraternal) twins: Two eggs fertilized by two sperm Genetically distinct, like siblings Cleavage Patterns (00:11:26 - 00:12:31) Spiral cleavage: Occurs at the 8-cell stage Radial cleavage: Occurs in protostomes and deuterostomes Differences in mouth and anus formation Determinate cleavage: https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 5/8 8/27/24, 2:16 PM Platform | Study Fetch Fate of blastomeres is not predetermined Indeterminate cleavage: Fate of blastomeres is predetermined Holoblastic cleavage: Even division throughout the embryo Embryos with little yolk Meroblastic cleavage: Uneven division Embryos with a lot of yolk Morula and Blastula (00:12:31 - 00:13:11) Morula: Ball of 12-16 cells Blastula: Formed after blastocoel (hollow space) is created Contains trophoblast (outer layer) and inner cell mass Trophoblast becomes extra-embryonic structures (placenta, amnion) Inner cell mass becomes the embryo Gastrulation (00:13:11 - 00:14:17) Blastula cells rearrange to form the germ layers: Ectoderm Mesoderm Endoderm Primitive streak forms, leading to the formation of the germ layers Ectoderm forms outer surface and central nervous system Mesoderm forms muscle, blood, kidneys, bone Endoderm forms internal organs Germ Layer Derivatives (00:14:17 - 00:14:35) Ectoderm: Outer surface Central nervous system Mesoderm: Muscle Blood system https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 6/8 8/27/24, 2:16 PM Platform | Study Fetch Kidneys Bone Endoderm: Internal organs Embryonic Development and Organ Formation Digestive Tube and Germ Cells (00:14:35 - 00:14:46) The digestive tube, pharynx, and lungs form as a budding off of the gastrointestinal tract The germ cells of the new embryo will also form during this process Ectoderm (00:14:46 - 00:15:07) Ectoderm Mnemonic: Ectoderm is the attracted derm, pretty skin and health Ectoderm will form: Epidermis and skin Nails Jaws and teeth Brain, central nervous system (CNS), and peripheral nervous system (PNS) Sensory parts of skin and nails Sweat glands Mesoderm (00:15:07 - 00:15:24) Mesoderm Mnemonic: Mesoderm means "of having sex" Mesoderm will form: Gonads Bones and skeleton Muscles Cardiovascular system Blood Spleen Endoderm https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 7/8 8/27/24, 2:16 PM Platform | Study Fetch (00:15:24 - 00:15:47) Endoderm Mnemonic: Endoderm is the "end internals of the end P TT" Endoderm will form: Epithelial lining of internal organs Pancreas Liver Thyroid Parathyroid Thymus Organogenesis (00:15:47 - 00:15:58) Organogenesis is the process by which organs are formed from the three germ layers Patterning and adult structure formation occurs during this process Neurulation (00:15:58 - 00:16:30) Neurulation is the formation of nervous tissue It begins with the formation of a neural plate from the ectoderm The neural plate then folds inward to form the neural tube, which will become the central nervous system Embryonic Models (00:16:30 - 00:17:58) In mammals, the amnion secretes amniotic fluid to cushion and protect the embryo The embryo will inhale and drink the amniotic fluid, then excrete it, recirculating the fluid If the embryo cannot excrete the fluid (e.g., renal agenesis), it can lead to birth defects The chorion forms the placenta, the allantois becomes the umbilical cord, and the yolk sac nourishes the fetus Chick embryos are nourished by a yolk sac, while human embryos are nourished by the placenta and umbilical cord https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce17e6d56e584fb7692c13/document?go=note 8/8