BIOL 106 Final Exam Study Guide Fall 2024 PDF

**Final Exam Study Guide** **The Cumulative final exam is worth 100 points and will have 50 questions. It will focus on the main concepts we have explored this semester and some of the details that make those concepts meaningful.** **This study guide is constructed to help you see big picture conc...

**Final Exam Study Guide** **The Cumulative final exam is worth 100 points and will have 50 questions. It will focus on the main concepts we have explored this semester and some of the details that make those concepts meaningful.** **This study guide is constructed to help you see big picture concepts we have developed throughout the semester and to see relationships between plants and animals.** Be able to sketch out processes and describe the dynamics before you start answering specific questions about them. Once you feel confident in your understanding, use the questions provided below to test yourself. Save the clicker questions, related LBL and Lab questions, and old exams for a final test of your knowledge prior to taking the comprehensive final. Study Guidelines for **SCIENCE SKILLS** part: From Lab: - Define **independent, dependent**, and **controlled variables** and explain their role in a scientific experiment. - Independent variable: the factor you change or manipulate to see its effect - ROLE: It's the cause or input in the experiment - Dependent variable: The factor you measure or observe as it responds. - Role: It's the effect or output of the experiment - Controlled Variable: The factors kept constant to ensure a fair test - Role: they prevent other variables from affecting the results - **Design a simple experiment** to study a question like the ones you explored in the plant module labs. - **Interpret** a graph like those you created using Excel in the plant module labs. Be sure to correctly interpret the error bars -- what do they represent? What do they tell you about differences seen between treatments? - Define "**standard deviation**" and understand what it tells you about the data from an experiment. - Explain the role of **statistics** in experimentation. - Interpret **a p-value** if given a scenario. - P-value shows the probability of getting your results (or more extreme ones) if the null hyptothesis is true - Low p-value (ex \0.05): Weak evidence against the Null hypothesis. Could be due to chance. - Example: A p-value of 0.03 means there's a 3% chance the results happened by random chance. This suggests a significant effect if your threshold is 0.05 Study Guidelines for **PLANTS** part: Focus on: - **Plant Diversity** -- know the key identifying characteristics of each plant group. Review both lecture and lab. Walk through the basic alternation of generations diagram. 1. Bryophytes (Mosses, Liverworts, Hornworts) a. **Key Characteristics:** i. Non-vascular (no xylem or phloem). ii. Gametophyte is the dominant generation. iii. Reproduce using spores. iv. Require water for fertilization (sperm swims to egg). 2. Seedless Vascular plants (Ferns, Horsetails, Club mosses). b. **Key Characteristics:** v. Vascular tissue (xylem and phloem) present. vi. Sporophyte is the dominant generation. vii. Reproduce using spores. viii. Still require water for fertilization. 3. **Gymnosperms (Conifers, Cycads, Ginkgo)** c. **Key Characteristics:** ix. Vascular tissue present. x. Sporophyte is the dominant generation. xi. Reproduce using seeds (naked seeds, not enclosed in fruit). xii. Do not require water for fertilization (pollen is dispersed by wind). 4. **Angiosperms (Flowering Plants)** d. **Key Characteristics:** xiii. Vascular tissue present. e. Sporophyte is the dominant generation. f. Reproduce using seeds enclosed in fruits. g. Flowers attract pollinators for fertilization. 5. **Alternation of Generations (simplified diagram)** h. **Sporophyte (2n):** xiv. Diploid generation that produces haploid spores by **meiosis**. i. **Spores (n):** xv. Grow into the **gametophyte** by mitosis. j. **Gametophyte (n):** xvi. Haploid generation that produces gametes (sperm and egg) by **mitosis**. k. **Fertilization:** xvii. Sperm and egg fuse to form a diploid **zygote**. l. **Zygote (2n):** xviii. Develops into the **sporophyte**, starting the cycle over. - **Plant Reproduction** -- Name the flower parts. Label the structures of a seed. - **Plant Structure** -- know the basic organ systems and what their functions are. Name the 3 tissue layers, dive deeper into the structures of xylem and phloem. - **Roots** - **Function** - Anchor the plant in the soil. - Absorb water and minerals. - Store nutrients. - **Stems** - **Function:** - Support the plant and hold leaves up for sunlight. - Transport water, nutrients, and sugars between roots and leaves. - **Leaves** - **Function:** - Main site of photosynthesis (capture sunlight to produce food). - Gas exchange through stomata (CO₂ in, O₂ out). - **The 3 Tissue Layers in Plants** - **Dermal Tissue** - **Function:** - Outer protective covering (like skin). - Prevents water loss and protects against pathogens. - **Specialized Structures:** - Cuticle: Waxy layer to prevent water loss. - Stomata: Openings controlled by guard cells for gas exchange. - **Ground Tissue** - **Function:** - Photosynthesis, storage, and support. - **Types:** - Parenchyma: General storage and photosynthesis. - Collenchyma: Flexible support. - Sclerenchyma: Rigid support. - **Vascular Tissue** - **Function:** - Transport materials throughout the plant. - **Xylem and Phloem: Vascular Tissue Details** - **Xylem** - **Function:** - Transports water and dissolved minerals from roots to the rest of the plant. - **Structure:** - Made of dead, hollow cells called **tracheids** and **vessel elements**. - Walls reinforced with lignin for strength. - **Phloem** - **Function:** - Transports sugars (food) from leaves to other parts of the plant. - **Structure:** - Made of living cells called **sieve tube elements** (connected end to end). - Supported by **companion cells** (help load and unload sugars). - **Plant Growth** -- describe the basic processes of primary and secondary growth. - **Primary growth** - Happens at the tips of roots and shoots (apical meristems) - Increases the plant's height - Produces new leaves, Flowers, and roots - **Secondary growth** - Occurs in stems and roots (Lateral meristems). - Increases the plant's thickness (woody growth). - Forms rings in trees (from vascular cambium). - **Plant Nutrition** - Understand the mutualisms of rhizobacteria and mycorrhizal fungi with plants. - **Plant Transport --** Describe the dynamics of transpiration for moving water through the xylem, and how sugar is moved in the phloem. Discuss the trade-offs associated with opening/closing stomata. - **Plant Hormones & Responses to External Stimuli** -- know the plant hormones and what they do (you won't need to know the mechanics here). Identify the external stimuli (e.g., light quality) plants respond to (you can skip the mechanics here as well). Focus on the material covered in lecture. Study Guidelines for **EVOLUTION** part: Focus on: - **Natural Selection:** Describe the process by which natural selection pushes a population toward increasing adaptation for the environment it occupies. Be able, if given a scenario, to identify the specific selective pressure (e.g., sexual selection, predation) pushing the change, and the outcome of the selection on the population. - Relate the process of natural selection to the predator-avoidance adaptations discussed in the Ecology unit. - **Origin of Species** -- Define and apply the biological species concept. Identify the various pre-zygotic and post-zygotic reproductive isolating mechanisms and how that leads to speciation. Distinguish between allopatric and sympatric situations and their roles in speciation. Understand the meaning of hybrid zones. - **Phylogeny -** Interpret a phylogenetic tree. Know the Linnean classification system. Know how to write a scientific name correctly \[lab\]. Study Guidelines for **ANIMAL** part: **ANIMAL DIVERSITY** Identify the following **[animals]** if given key traits: Knowing the tree is very helpful for this. Questions will be phrased "You find an animal with \_\_\_\_\_\_, \_\_\_\_, and \_\_\_\_\_ traits. Who is it?". - - Porifera - Cnidaria - Platyhelminthes - Nematoda - Mollusca - Annelida - Arthropoda (trilobites vs chelicerates vs myriopods vs pancrustaceans (& crustacea vs insects) - Echinodermata - Chordata **ANIMAL DIGESTION & NUTRITION** - 1. **Mouth** a. **What happens?** Mechanical digestion (chewing) and chemical digestion start here. b. **Enzyme(s):** Salivary amylase breaks down starch into maltose. 2. Esophagus c. **What happens?** Food moves via peristalsis (muscle contractions) to the stomach. d. **Enzyme(s):** None active here; it\'s a transport tube. 3. Stomach e. **What happens?** Food is mixed with gastric juices, becoming chyme. Proteins begin to break down. f. **Enzyme(s):** i. Pepsin: Breaks proteins into smaller peptides. g. **Environment:** Acidic (due to hydrochloric acid). 4. Small intestine (Duodenum, Jejunum, Ileum) h. Duodenum (Digestion): ii. **What happens?** Most chemical digestion occurs. Enzymes from the pancreas and bile from the liver act here. iii. **Enzyme(s):** 1. Pancreatic amylase: Continues starch digestion. 2. Lipase: Breaks fats into glycerol and fatty acids. 3. Proteases (trypsin, chymotrypsin): Break proteins into amino acids. 4. Maltase, lactase, sucrase: Break disaccharides into monosaccharides. 5. Bile (not an enzyme): Emulsifies fats for easier breakdown. i. Jejunum and Ileum (absorption): iv. **What happens?** Nutrients (amino acids, sugars, fatty acids, vitamins) are absorbed into the blood or lymph. 5. Large Intestine (Colon) j. What happens? Water and electrolytes are absorbed. Remaining material is compacted into feces. k. **Enzyme(s):** None active here; bacteria aid in breaking down some fibers and produce vitamins (like vitamin K). 6. Rectum and Anus l. **What happens?** Waste (feces) is stored in the rectum and eliminated through the anus. - - - **Carbon (C)** - **Reservoir for Plants:** Atmosphere (CO₂). - **How Animals Obtain It:** By eating plants or other animals (carbon is in carbohydrates, fats, and proteins). - **Nitrogen (N)** - **Reservoir for Plants:** Soil (nitrates and ammonium from nitrogen-fixing bacteria and decomposition). - **How Animals Obtain It:** By eating plants or other animals (nitrogen is in proteins and DNA/RNA). - **Phosphorus (P)** - **Reservoir for Plants:** Soil and rocks (phosphate ions released through weathering). - **How Animals Obtain It:** By eating plants or other animals (phosphorus is in DNA, RNA, and ATP). - **Water (H₂O)** - **Reservoir for Plants:** Soil and groundwater (absorbed through roots). - **How Animals Obtain It:** Drinking water or consuming water-rich food. - **Oxygen (O)** - **Reservoir for Plants:** Atmosphere (O₂ for respiration and H₂O for photosynthesis). - **How Animals Obtain It:** Breathing oxygen from the air (used in cellular respiration). - - **Foliage feeder**: Rich in **carbohydrates** (cellulose), some **proteins**. - **Frugivore**: High in **carbohydrates** (sugars), small amounts of **lipids** (from seeds). - **Granivore**: High in **carbohydrates** (starches), some **proteins** and **lipids** (from seeds). - **Carnivore**: High in **proteins** and **lipids** (from animal tissues) - - **Digestive Tract Features:** - **Herbivores**: Longer digestive tracts (e.g., large cecum) to break down tough plant fibers like cellulose. - **Carnivores**: Shorter digestive tracts because animal tissues are easier to digest. - Teeth: - **Herbivores**: Broad, flat molars for grinding plants; reduced canines. - **Carnivores**: Sharp canines for tearing meat; pointed premolars and molars for cutting. **PHYSIOLOGY** - **Surface area to volume ratio** -- relate high surface area to volume ratios to movement of molecules. Identify systems that utilize this to increase efficient transfer. You saw this in the digestive system, respiratory/circulatory system in particular. - **Movement of vital molecules**: - **Circulation** of gases and nutrients in animals. Know the basic path of the circulatory system and the direction of net movement of these key molecules during gas exchange in the lungs and body tissues. - **Basic Path of Circulatory System** - **Heart (right side)** pumps **deoxygenated blood** to the lungs via pulmonary arteries. - In the **lungs**, blood picks up **O₂** and releases **CO₂** (gas exchange). - **Oxygenated blood** returns to the heart (left side) via pulmonary veins. - **Heart (left side)** pumps oxygenated blood to the body through systemic arteries. - In **body tissues**, blood delivers **O₂** and nutrients, picking up **CO₂** and waste (gas exchange). - **Deoxygenated blood** returns to the heart (right side) via systemic veins. - **Net Movement During Gas Exchange:** - **In the lungs** - **O₂** moves from the alveoli into the blood. - **CO₂** moves from the blood into the alveoli. - In **body tissues**: - **O₂** moves from blood to cells. - **CO₂** moves from cells to blood. - **Biological Principle: Role of specific ions in physiological processes:** Na^+^, K^+^, and Ca^2+^ - **What role do these ions play in nerve signaling, reproduction (blocks to polyspermy), muscle contraction, and osmoregulation in the nephron. You've also seen them as vital nutrients for plant growth.** - Biological Principle: Using **ions and ion gradients to drive physiology** - Describe the **action potential** as an example of concentration gradients in action -- what is the role of Na^+^, K^+^, and Ca^2+^? What is the gradient for these (that is, higher on which side of the cell membrane)? - Describe how and where this principle applies to **gas exchange** (O~2~ and CO~2~). What is the gradient of these gases in the circulatory system/respiratory system interfaces in the lungs and tissues? - Describe the action in the **nephron** -- specifically in the descending loop of Henle and collecting duct as example of passive movement of molecules (H~2~O and NaCl) and the action in the ascending loop of Henle as an example of the role of pumps to facilitate concentration gradients. - Describe the control of **fertilization** -- what is the role of Na^+^ and Ca^2+^ in preventing polyspermy? - **Action Potential and Ion Gradients** - **Na+ (Sodium):** Higher outside the cell, moves inward during depolarization. - **K+ (Potassium):** Higher inside the cell, moves outward during repolarization. - **Ca2+ (Calcium):** Higher outside the cell, enters at the synapse to trigger neurotransmitter release. - **Gas Exchange and Gradients** - **O2 (Oxygen):** Higher in the alveoli than in blood, diffuses into blood. Higher in blood than tissues, diffuses into cells. - **CO2 (Carbon Dioxide):** Higher in tissues than in blood, diffuses into blood. Higher in blood than alveoli, diffuses into alveoli. - **Nephron and Passive/Active Movement** - **Descending Loop of Henle:** Passive water reabsorption; medulla is hypertonic. - **Ascending Loop of Henle:** Pumps actively transport NaCl; impermeable to water. - **Collecting Duct:** Water reabsorbed via osmosis; controlled by ADH. - **Fertilization and Ion Roles** - **Na+:** Rapid influx alters membrane potential, preventing polyspermy (fast block). - **Ca2+:** Wave of Ca2+ triggers cortical granules to harden zona pellucida (slow block). - Biological Principle: using **counter-current exchange** to maximize efficiency of molecule movement - For **gas exchange**, describe the movement of oxygen and carbon dioxide between the tissues and blood and between blood and gills. - In the **nephron**, describe the role of the interstitial osmolarity encountered by the filtrate as it descends in the loop of Henle and collecting duct as an example of this. **ANIMAL RESPONSES TO THE ENVIRONMENT (both internal and external environments) (Carloye)** - Name the **hormones** responsible for controlling blood sugar and calcium levels. - Identify the stimulus, the source tissue, the target tissue and the response of the target tissue to the hormones. - **Hormones Controlling Blood Sugar** - **Insulin** - **Stimulus:** High blood sugar levels. - **Source Tissue:** Pancreas (beta cells in the islets of Langerhans). - **Target Tissue:** Liver, muscle, and fat cells. - **Response:** - Liver: Stores glucose as glycogen. - Muscle and fat: Take up glucose from the blood. - Overall: Lowers blood sugar levels. - **Glucagon** - **Stimulus:** Low blood sugar levels. - **Source Tissue:** Pancreas (alpha cells in the islets of Langerhans). - **Target Tissue:** Liver. - **Response:** - Liver: Breaks down glycogen into glucose and releases it into the blood. - Overall: Raises blood sugar levels. - **Hormones Controlling Blood Calcium** - **Parathyroid Hormone (PTH)** - **Stimulus:** Low blood calcium levels. - **Source Tissue:** Parathyroid glands. - **Target Tissues:** Bones, kidneys, and intestines. - **Response:** - Bones: Release calcium into the blood. - Kidneys: Reabsorb calcium and activate vitamin D. - Intestines: Increase calcium absorption (via activated vitamin D). - Overall: Raises blood calcium levels. - **Calcitonin** - **Stimulus:** High blood calcium levels. - **Source Tissue:** Thyroid gland (parafollicular or C cells). - **Target Tissues:** Bones and kidneys. - **Response:** - Bones: Store more calcium. - Kidneys: Excrete excess calcium. - Overall: Lowers blood calcium levels - Describe the overall layout of the vertebrate **nervous system** (central & peripheral nervous system) - **Central Nervous System (CNS)** - **Parts:** Brain and spinal cord. - **Function:** - Processes information and makes decisions. - Controls body functions and coordinates responses. - **Peripheral Nervous System (PNS)** - **Parts:** All nerves outside the CNS (cranial and spinal nerves). - **Function:** - Connects the CNS to the rest of the body. - Transmits signals between the CNS and organs, muscles, and skin. - **Divisions of the Peripheral Nervous System** - **Somatic Nervous System** - **Function:** Controls voluntary movements (e.g., moving your arm). - Connects CNS to skeletal muscles. - **Autonomic Nervous System** - **Function:** Controls involuntary actions (e.g., heartbeat, digestion). - **Divisions:** - **Sympathetic:** \"Fight or flight\" responses. - **Parasympathetic:** \"Rest and digest\" responses. Study Guidelines for **ECOLOGY** part: **The following material is from the [ECOLOGY] section -- I will update it as necessary depending on what we are able to explore in the time remaining.** **COMMUNITY ECOLOGY** - What is a "community"? - A **community** in ecology is a group of different species that live in the same area and interact with each other. These interactions can include: - **Competition** (for resources like food or space) - **Predation** (one species eats another) - **Symbiosis** (close relationships like mutualism, commensalism, or parasitism) - Communities include all the living organisms (plants, animals, fungi, microbes) in a specific location. - What interactions structure the community? - Who gets harmed, who benefits in each type of interaction? - How do these interactions create an interdependence underlying community structure? Relate this to food web diagrams you developed in lab *(lab)* - Distinguish between "top-down" and "bottom-up" control of species composition in a community *(lab)* - Know the stories of keystone species and their role in structuring their communities (and the consequences of their removal (the kelp forest, rocky intertidal, and Yellowstone*) (lab)* - **Community Interactions:** - **Mutualism**: Both species benefit (e.g., bees pollinating flowers). - **Commensalism**: One benefits, the other is unaffected (e.g., barnacles on whales). - **Predation**: Predator benefits, prey is harmed. - **Parasitism**: Parasite benefits, host is harmed (e.g., ticks on mammals). - **Competition**: Both species are harmed as they compete for the same resources. - **Interdependence and Food Webs:** - Interactions create a balance in community structure by linking species. - Food webs show how energy and nutrients flow; changes in one species affect others (e.g., removing a prey species impacts predators). - **Top-Down vs. Bottom-Up Control:** - **Top-Down**: Predators control the population sizes of prey and producers (e.g., wolves in Yellowstone). - **Bottom-Up**: Producers (plants) control the abundance of herbivores and predators (e.g., nutrient availability limits plant growth). - **Keystone Species and Their Communities:** - **Kelp Forest**: Sea otters (keystone species) control sea urchin populations; removing otters leads to kelp destruction. - **Rocky Intertidal**: Starfish (keystone species) maintain diversity by preying on dominant species like mussels. - **Yellowstone**: Wolves (keystone species) control elk populations, allowing vegetation to recover and benefiting other species. - - What is a niche? - What is the difference between fundamental vs. realized niches? - **Niche:** **A niche is the role a species plays in its environment, including its habitat, interactions, and resource use.** - **Fundamental vs. Realized Niche:** - **Fundamental Niche**: The full range of conditions and resources a species could theoretically use without competition or other limiting factors. - **Realized Niche**: The actual conditions and resources a species uses due to competition, predation, or other constraints. - - **Foundational Species:** - Have a large physical or structural impact on their environment (e.g., creating or maintaining habitats). - Example: Coral in coral reefs or trees in forests. - **Keystone Species:** - Have a disproportionately large effect on community structure relative to their abundance. - Often regulate populations and maintain ecosystem balance. - Example: Wolves in Yellowstone controlling prey populations like elk. - - Be able to interpret a food web diagram *(lecture and lab):* What do the arrows indicate? What is the highest trophic level of a given organism? - **Trophic Levels in a Food Chain/Web:** - **Producers**: Plants or other autotrophs that make energy through photosynthesis. - **Primary Consumers**: Herbivores that eat producers. - **Secondary Consumers**: Carnivores that eat primary consumers. - **Tertiary Consumers**: Carnivores that eat secondary consumers. - **Quaternary Consumers** (if present): Top predators with no natural enemies. - **Food Web Diagram:** - **Arrows**: Show the flow of energy and nutrients, pointing from the food source to the consumer (e.g., plant → herbivore → carnivore). - **Highest Trophic Level**: The organism with no predators (e.g., apex predator like an eagle). - What resources are transferred from one trophic level to the next? - **Energy**: Stored in organic molecules, primarily as carbohydrates, proteins, and lipids. - **Biomass**: Physical material consumed (e.g., plant matter or prey). - **Nutrients**: Essential elements like nitrogen (N), phosphorus (P), and carbon (C). - Which nutrients can be limiting factors for a community? - **Nitrogen (N):** Essential for proteins and DNA; often limits plant growth. - **Phosphorus (P):** Needed for ATP, DNA, and cell membranes; limits growth in freshwater ecosystems. - **Potassium (K):** Important for enzyme function and water regulation in plants. - **Iron (Fe):** Limits growth in marine ecosystems (phytoplankton). - **Carbon (C):** Can limit productivity if unavailable in usable forms. - - - Sketch the terrestrial carbon cycle, following C as it moves and gets incorporated into new molecule at each stop along the way. Identify.... - the reservoirs where large quantities are stored (fossil fuels, wood, atmosphere) - the parts where chemicals cycle relatively quickly and - where/how they move from reservoirs back into active cycles. - - the reservoirs where large quantities are stored, - the mechanism(s) by which nitrogen gas is converted to a useable form of nitrogen - - **ECOLOGICAL SUCCESSION:** - - - - - - **POPULATION ECOLOGY** - Draw or interpret a graph showing exponential growth of a population. - Under what conditions do populations experience exponential growth? - What symbol is used for it? - Draw or interpret a graph showing logistic growth of a population. - What conditions lead to the leveling-off of the curve? - What is "carrying capacity"? What symbol is used for it? - What are some density-dependent limits on population growth? - What are some density-independent limits on population growth? Distinguish between these terms. - Every organism has a limited amount of energy. How is energy allocated toward cell maintenance, growth and reproduction? What is the vast majority of it used for in individuals? - Relate this energy allocation to life history strategies. - Which combinations of traits are associated with equilibrial (K-selected) life history strategies? - Which combinations of traits are associated with opportunistic (r-selected) life history strategies? - If given a single trait of a species, determine whether it is aligned with r-selected (opportunistic) or K-selected (equilibrial) life history traits. Then be able to describe or choose other traits that it is likely to have based on that determination. - Interpret graphs of survivorship curves, population age structure, life history tables. - Correlate life history traits with the types of survivorship curves. - Discuss the mortality patterns associated with each type of survivorship curve. 1. **Type I Curve (Convex)**: a. **Graph Shape**: High survival in early/middle life, steep decline in old age. b. **Life History Traits**: Few offspring, high parental care, long lifespan (e.g., humans, elephants). c. **Mortality Patterns**: Low mortality in young; most deaths occur in older individuals. 2. **Type II Curve (Linear)**: d. **Graph Shape**: Constant mortality rate throughout life. e. **Life History Traits**: Moderate number of offspring, some parental care (e.g., birds, small mammals). f. **Mortality Patterns**: Equal likelihood of death at any age. 3. **Type III Curve (Concave)**: g. **Graph Shape**: High mortality early in life, with survivors living longer. h. **Life History Traits**: Many offspring, little or no parental care (e.g., fish, insects, plants). i. **Mortality Patterns**: Most individuals die young; few reach maturity. 4. **Population Age Structure:** j. **Broad Base (Pyramid Shape)**: Indicates rapid population growth (common in Type III). k. **Uniform Width**: Stable population with equal age distribution (associated with Type II). l. **Narrow Base**: Declining population, low birth rates, aging population (linked to Type I). 5. **Life Tables:** m. Combine survivorship and reproduction data to summarize population dynamics. n. Help predict population growth based on survival rates and reproductive output at different ages. **ENERGY FLOW:** - What is the path of energy flowing through an ecosystem (starting with solar energy)? 1. **Solar Energy**: The sun provides energy that is captured by producers. 2. **Producers (Autotrophs)**: Plants, algae, and some bacteria convert solar energy into chemical energy through photosynthesis. 3. **Primary Consumers (Herbivores)**: These organisms eat producers and obtain energy stored in plants. 4. **Secondary Consumers (Carnivores)**: These animals eat primary consumers to obtain energy. 5. **Tertiary Consumers (Top Predators)**: These organisms eat secondary consumers for energy. 6. **Decomposers (Detritivores)**: Fungi, bacteria, and other organisms break down dead plants and animals, recycling nutrients and releasing energy as heat. - Name the trophic levels and how energy is transferred between them. Be sure to include detritivores and decomposers. Trophic levels and energy transfer. 1. **Producers (Trophic Level 1)**: Plants, algae, and some bacteria capture solar energy through photosynthesis and store it as chemical energy.\ *Energy transfer*: Producers are consumed by primary consumers. 2. **Primary Consumers (Trophic Level 2)**: Herbivores eat producers to obtain energy.\ *Energy transfer*: Primary consumers are eaten by secondary consumers. 3. **Secondary Consumers (Trophic Level 3)**: Carnivores eat primary consumers for energy.\ *Energy transfer*: Secondary consumers may be eaten by tertiary consumers. 4. **Tertiary Consumers (Trophic Level 4)**: Top predators consume secondary consumers.\ *Energy transfer*: When they die, their energy is passed to decomposers. 5. **Detritivores and Decomposers**: Organisms like fungi, bacteria, and detritivores (e.g., earthworms) break down dead material from all trophic levels. They recycle nutrients back into the ecosystem and release some energy as heat. 1. Energy is transferred through consumption, with some lost as heat at each step. 2. Only about **10%** of energy is passed from one trophic level to the next, while the rest is used in metabolism or lost as heat. - In what ways is energy lost as it travels through the ecosystem? How much energy is lost between trophic levels? - Describe this as a food web as well as an energy pyramid. - Ways energy is Lost 1. **Heat Loss**: Most energy is lost as heat during metabolism (respiration). 2. **Incomplete Consumption**: Not all parts of an organism are eaten (e.g., bones, roots). 3. **Incomplete Assimilation**: Some energy in consumed food is not digested and passes as waste. - **Energy Lost between Trophic Levels** - **Heat Loss**: Most energy is lost as heat during metabolism (respiration). - **Incomplete Consumption**: Not all parts of an organism are eaten (e.g., bones, roots). - **Incomplete Assimilation**: Some energy in consumed food is not digested and passes as waste. - **Food Web** - In a food web, energy flows from producers to various consumers (primary, secondary, tertiary) and eventually to decomposers. At each link in the web: - Organisms use most of their energy for survival (maintenance, movement, reproduction). - Only a fraction is passed to the next trophic level. - Energy pyramid: An energy pyramid visually shows the energy available at each trophic level 1. **Base (Producers)**: Largest energy store from the sun. 2. **Primary Consumers**: Receive 10% of the energy from producers. 3. **Secondary Consumers**: Receive 10% of the energy from primary consumers. 4. **Tertiary Consumers**: Receive 10% of the energy from secondary consumers. When organisms take in energy, how is it allocated between maintenance, growth and reproduction? - Maintenance: energy is used to sustain basic physiological functions like respiration, immune defense, and homeostasis. - Growth: Energy is invested in building body mass, which is particularly important in early life stages. - Reproduction: Energy is used to produce offspring, including mating efforts, gestation and prenatal care. - Relate this to life history traits. - Short-lived species (Ex., insects) often prioritize reproduction over growth, investing heavily in producing many offspring quickly. - Long lived species (Ex., elephants) allocate more energy to maintenance and slower growth early in life, delaying reproduction to maximize survival and future reproductive success. - Trade-offs occur because energy is finite: investing heavily in one area (Ex., reproduction) often reduces energy available for maintenance or growth, influencing survival and lifetime reproductive success. This balance shapes an organism life history strategy **COMMUNITY DYNAMICS AS SELECTIVE PRESSURES (ADAPTATIONS)** - Describe the role of predation in community dynamics and evolutionary outcomes (via natural selection) including: - Predation-avoidance adaptations including camouflage, toxicity+warning coloration, Batesian mimicry, masquerade. - **Role of Predation in Community Dynamics:** - Predation helps shape population sizes and species interactions, maintaining balance in ecosystems. - It acts as a selective pressure, driving the evolution of traits that improve survival. - **Predation-Avoidance Adaptations:** - **Camouflage**: Blending with the environment to avoid detection (e.g., stick insects). - **Toxicity + Warning Coloration**: Bright colors signal toxicity to deter predators (e.g., poison dart frogs). - **Batesian Mimicry**: Harmless species mimic toxic ones to avoid predation (e.g., a non-venomous snake resembling a venomous one). - **Masquerade**: Resembling inanimate objects to avoid being seen as prey (e.g., leaf insects).