Biology - B4.2 Ecological Niches -kognity | Quizlet

What is a Specialist Species?

Definition: Organisms with a narrow set of conditions for survival.

Example:Koala (Phascolarctos cinereus): Lives in Australia and feeds only on eucalyptus leaves.

What is a Generalist Species?

Definition: Organisms that can survive in a broad range of environments and adapt to different conditions.

Example:Black rat (Rattus rattus): Found in diverse habitats globally.

Who Adapts Better to Environmental Changes?

Generalist species:More adaptable to changing or fluctuating conditions.

Specialist species:Vulnerable to changes due to their specific needs.

What is an Ecological Niche?

Definition: The role and interactions of an organism within its ecosystem, including:Habitat (where it lives).Role (what it does).Impacts (how it affects the ecosystem).

What Determines a Species' Distribution?

Biotic factors: Living components of the ecosystem. Examples:

Competition for resources.

Predators and parasites.

Diseases.

Abiotic factors: Non-living environmental factors. Examples:

Temperature.

Precipitation.

Sunlight.

pH levels (soil or water).

Examples of Species and Environmental Needs

Bryophytes:Need moderate temperatures, water, substrate to grow on, and indirect light.

Cactus:Thrive in poor sandy soil, higher temperatures, and need less water.

How Can Organisms Impact Their Environment?

Beavers:

Build dams to stem rivers.

Result: Flooding, creation of wetlands, and increase in biodiversity.

Example: Beaver dams create wetlands which provide habitats for various species, enhancing ecosystem biodiversity.

What Role Do Worms Play in the Soil?

Earthworms:Break down dead organic material in soil.Improve soil quality by:Increasing nutrient content.Improving drainage.Improving soil structure.Key role in maintaining healthy soil ecosystems.

What is Obligate Anaerobic Respiration?

Obligate Anaerobes:

Cannot survive in the presence of oxygen (oxygen is toxic).

Use other compounds as electron acceptors (e.g., sulfate, nitrates, iron, manganese).

Example: Clostridium difficile, which causes bowel infections.

What is Facultative Anaerobic Respiration?

Facultative Anaerobes:Can survive in both aerobic and anaerobic conditions.Prefer oxygen (aerobic respiration) for higher ATP yield.Switch to fermentation if oxygen is unavailable.Example: Escherichia coli (E. coli), which is involved in wastewater treatment.

What is Obligate Aerobic Respiration?

Obligate Aerobes:Require oxygen as the final electron acceptor in respiration.Cannot survive without oxygen.Example: Mycobacterium tuberculosis, which causes tuberculosis.

How Can You Test the Respiration Method of Bacteria?

Purpose: To test where bacteria migrate in response to oxygen availability.

Method:Bacteria grow in a medium where oxygen is absent at the bottom and present at the top.Results:Obligate aerobes move to the top.Obligate anaerobes move to the bottom.Facultative anaerobes are found in the middle.

How Does the Thioglycolate Experiment Work?

Thioglycolate Medium:Removes oxygen and allows oxygen diffusion from the top.Helps visualize bacteria's oxygen preference.Inoculated bacteria migrate to areas where they can respire (aerobic or anaerobic).

True or false?

Abiotic factors are the living parts of an ecosystem.

False

F

Explanation:

Biotic factors refers to the living parts of the ecosystem, such as competition with other species for resources, disease, predators and parasites. The abiotic factors refers to the non-living parts of the ecosystem such as the temperature, rainfall, wind, the amount of sunlight, the pH of the water and the soil.

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A________ is an organism that can only live in a narrow range of conditions.

specialist

Which chemical can be used as an electron acceptor by obligate anaerobes.

sulfate

Explanation

Obligate anaerobes live in environments devoid of oxygen - they can use other molecules as electron acceptors. Sulfates are one such group.

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What is Nutrition in Organisms?

Nutrition is a fundamental life process by which organisms obtain energy for growth, repair, and metabolic processes.

Producers: Organisms that generate their own source of nutrition (e.g., plants, algae).

Consumers: Organisms that take in nutrition from external sources (e.g., animals, fungi).

What is the Oriental Hornet's Unique Nutrition Process?

The oriental hornet (Vespa orientalis) can:

Use normal feeding methods (like other animals).

Absorb sunlight through pigments in its cuticle to generate electrical energy.

This allows the hornet to carry out metabolic processes similar to the liver.

What is the Difference Between Autotrophs and Heterotrophs?

Autotrophs: Organisms that generate their own nutrition using energy from the sun.Examples: Plants, algae, some prokaryotes.

Heterotrophs: Organisms that obtain nutrition from external sources (cannot produce their own).Examples: Animals, humans.

What is Photosynthetic Nutrition?

Photosynthesis: The process by which autotrophs use light energy to convert carbon dioxide and water into glucose and oxygen.

Photosynthesis Equation:6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

This process converts light energy into chemical energy stored in glucose.

What Organelles Are Involved in Photosynthesis?

Chloroplasts: Organelles that contain photosynthetic pigments to capture light energy.Function: Convert light energy into organic molecules (e.g., glucose).Found mainly in the leaves of plants, and in some stems and algae.

How Do Photosynthetic Prokaryotes Perform Photosynthesis?

Prokaryotes (e.g., cyanobacteria) lack chloroplasts.

They have infoldings of the plasma membrane where photosynthesis takes place.

This allows them to perform photosynthesis despite not having membrane-bound organelles like chloroplasts.

Where Else Can Chloroplasts Be Found Besides Leaves?

Chloroplasts are most commonly found in leaves, but can also be present in:Stems of some plants.Thallus (flattened blade) of algae, which lack the structure of true plants.

What is Holozoic Nutrition?

Holozoic Nutrition refers to the process by which organisms take in solid or liquid food internally.

Example Organisms: Most animals, protozoa, and Amoebas.

Process: The food is digested and broken down into organic molecules, which are then used for growth and development.

What is Mixotrophic Nutrition?

Mixotrophs can use both autotrophic (photosynthesis) and heterotrophic (ingestion) methods to gain nutrition.

Examples: Certain marine plankton like Paramecium bursaria.

Example Process: Can photosynthesize (like plants) to absorb carbon dioxide and also ingest food (like animals) to obtain nutrients.

Relevance: Mixotrophic plankton are important for studying climate change as they can shift between autotrophy and heterotrophy depending on environmental conditions.

What is Saprotrophic Nutrition?

Saprotrophic Nutrition involves secreting digestive enzymes to break down dead organic matter (like dead plants and animals).

The simpler molecules from this breakdown are then absorbed by the organism.

Examples: Fungi (e.g., mushrooms), certain bacteria (e.g., Escherichia coli), and yeast (e.g., Saccharomyces cerevisiae).

Importance: These organisms play a vital role in recycling carbon and nitrogen from dead organic matter, helping to decompose leaves and logs on the forest floor.

How Do Saprotrophs Contribute to Ecosystems?

Ecological Role: Saprotrophs are essential for the recycling of nutrients (carbon, nitrogen) by breaking down dead organic material.

Example: Fungi like mushrooms decompose cellulose, hemicellulose, and pectin in dead plant material.

Without saprotrophs, organic litter would build up, and nutrients would not return to the soil.

What is the Role of Cordyceps Fungi?

Cordyceps is a parasitic fungus that attacks insects like ants.

It kills the insect and then feeds on its body using saprotrophic nutrition.

How Does Mixotrophy Affect Marine Plankton?

Effect of Climate Warming: As the aquatic environment warms, mixotrophic plankton shift from an autotrophic mode (using photosynthesis) to a heterotrophic mode (eating other organisms).

This shift could result in an increase in carbon dioxide emissions, further contributing to ocean warming and climate change.

What is the Classification of Archaea?

Archaea is a domain of unicellular organisms that lack a true nucleus (like bacteria).

Distinction from Bacteria: Archaea have different biochemistry, and their cell walls contain polysaccharides, not peptidoglycan like bacteria.

Archaea are thought to be the most ancient organisms.

How Do Archaea Obtain Nutrition?

Archaea can be:Chemoautotrophs: Use oxidation of inorganic chemicals (e.g., sulfur, hydrogen sulfide, iron, ammonia) for energy.Photoautotrophs: Use light as their energy source (like plants).Heterotrophs: Obtain energy from organic compounds, often through methanogenesis (producing methane).

9. Where Can Archaea Be Found?

: Archaea are often found in harsh, extreme environments like:Hot springsDeep sea hydrothermal ventsHigh sulfur or salt environments

These environments are where archaea have evolved enzymes that allow them to survive under extreme conditions, like high temperatures or extreme pH levels.

Halophiles are archaea that thrive in environments with high salt concentrations.

Example: They can be found in salt lakes or salt mines.

Identify which mode of nutrition externally secretes digestive enzymes.

saprotrophic

Explanation

Saprotrophs secrete digestive enzymes externally and then the broken down compounds are reabsorbed by the organism. Fungi are an example of saprotrophs.

Identify how archaea and bacteria differ.

Bacteria have cell walls made of peptidoglycan but archaea have them made of polysaccharides

Explanation

Originally grouped together, Archaea is now classified distinctly from Bacteria. Both types of organisms are unicellular, both are prokaryotic (do not contain membrane-bound organelles) and both contain circular, naked DNA. However, Bacteria have cell walls made of peptidoglycan but archaea have them made of polysaccharides.

Identify the reason why scientists think that mixotrophs may act as an early warning system for climate change.

When placed in warm water - They have been shown to switch to a heterotrophic mode of nutrition.

Explanation

In experiments analysing the warming of the aquatic environment, it was found that the mixotrophs shifted away from an autotrophic mode of nutrition to a heterotrophic system. If scientists tested for the type of energy system that mixotrophs were using - this could indicate that oceans were warming in response to climate change.

What is the Cookiecutter Shark?

Scientific Name: Isistius brasiliensis

Size: Adult males reach only 42 cm in length.

Unique Bite: The shark is responsible for creating cookiecutter-shaped holes in prey, submarines, and even humans.

Feeding Mechanism:The shark secures itself to its prey using its lips and vacuum created by pulling back its tongue.It then uses its upper teeth to anchor itself and the lower teeth (triangular) to slice into the prey.A quick body rotation results in the removal of a circular plug of tissue from the prey.

How Does the Cookiecutter Shark's Dentition Aid in Feeding?

The upper teeth help the shark anchor itself while the lower teeth are used to cut into the prey.

The suction mechanism and sharp teeth work together to allow the shark to remove a circular plug from the prey.

How Do Human Teeth Differ from Shark Teeth?

Human Teeth (Homo sapiens):Humans are omnivores with teeth suited for both plant and animal matter.Molars for grinding, incisors for cutting, and canines for tearing.Teeth are highly mineralized and capable of enduring wear, making them well-preserved in the fossil record.

Shark Teeth (Cookiecutter Shark):Sharp, triangular teeth for slicing into prey.Designed for removing chunks of flesh rather than chewing.Sharks generally don't chew their food but instead tear pieces off and swallow them whole.

What is the Difference Between Hominins and Hominids?

Hominins: Refers to modern humans (Homo sapiens) and their immediate ancestors.

Hominids: Includes all great apes (gorillas, chimpanzees, orangutans) and hominins (humans and their ancestors).

Hominid vs. Hominin: All hominins are hominids, but hominids also include non-human great apes.

How Do Early Hominin Teeth Compare to Other Hominids?

Early hominin teeth are often compared to those of great apes (chimpanzees, gorillas, orangutans).

This comparison helps scientists infer dietary habits of early human ancestors and evolutionary adaptations in tooth morphology for different diets.

What Can Teeth Tell Us About Diet in Modern Humans?

Generalists: Humans are capable of consuming both plant and animal products.

Diet Variation:Hadza (Tanzania): Primarily a plant-rich diet with some meat.Inuit: Mostly meat-based diet due to environmental factors (extreme cold, limited plant resources).

Teeth Function: Human teeth are versatile, enabling us to eat a variety of foods, unlike specialized teeth in carnivores or herbivores.

What Are the Functions of Different Types of Teeth in Humans?

Incisors: Used for cutting food, typically plant material or meat.

Canines: Used for tearing food, often meat.

Premolars and Molars: Used for grinding and chewing, especially plant material and fibrous foods.

What is the Significance of Early Hominin Dentition?

Early hominins had large teeth designed to chew fibrous plant material.

High-volume consumption of plant material was needed to get enough energy.

As hominins started eating more energy-rich meat, their digestive systems could shrink, allowing more energy for brain development.

Teeth and jaw size were reduced over time due to less chewing required by the switch to a more energy-dense diet.

What Were the Key Features of Archaic Megadont Hominins?

Teeth:Large teeth with thick enamel for grinding tough, fibrous foods.Chewing occurred primarily at the back of the jaw.

Physical Features:Large chewing muscles resulted in a wide face.Presence of the sagittal crest indicated strong jaw muscles and grinding ability.

Diet: Likely herbivores that consumed tough grasses and sedges.

Nickname: "Nutcracker Man" due to their ability to grind tough foods.

What are the Key Characteristics of Modern Humans (Homo sapiens)?

hysical Features:Jaws are less heavily developed, with smaller teeth compared to earlier hominins.Modern humans are generalists, able to consume both plant and animal products.

Diet: Varied, including hunting, gathering, and food storage.

Global Distribution: Homo sapiens evolved in Africa but now inhabit the entire planet.

What are the Evolutionary Trends in Hominin Dentition?

ver time, the face became more vertical and the canines and jaws became shorter.

Teeth Arrangement: In modern humans, teeth are arranged in a tight U-shape.

Dietary Shift: Early hominins ate more fibrous plant material, while later hominins incorporated more animal products, leading to reduced tooth size and less need for extensive chewing.

How Did the Diet of Hominins Affect Their Dentition?

Herbivorous Ancestors: Early hominins, such as Paranthropus robustus, had large, thick teeth for grinding tough plants.

Omnivorous Species: Later hominins like Homo floresiensis and Homo sapiens developed smaller teeth due to a diet with a mix of plants and animals.

The shift to eating meat led to smaller jaws and teeth since less chewing was required.

How Do Dentition and Diet Relate to Brain Development in Hominins?

Early hominins consumed fibrous plant material, requiring large teeth and jaws for grinding, which also involved a larger, more energy-demanding digestive system.

Diet shift to meat: By consuming higher-energy foods like meat, hominins could reduce their digestive systems and allocate more energy to brain development.

Smaller teeth and jaws in later hominins like Homo sapiens are a result of less chewing and a more energy-dense diet.

____ include modern and extinct humans and their immediate ancestors.

homins

Determine what a large sagittal crest indicates.

There were large jaw muscles for chewing plant and nut material

Explanation

The large sagittal crest is the place of attachment for the jaw muscles and indicates that they had strong chewing motion needed for breaking up plant material and nuts.

What are the Key Adaptations of Herbivores for Feeding on Plants?

Mandibles: Some herbivorous insects have strong mandibles used for cutting, tearing, and crushing plant material.

Specialized Mouthparts: Insects like aphids have a stylet, a straw-like structure to access plant fluids (phloem). This allows them to feed on internal plant material by secreting a gel-like saliva to protect the plant tissue and facilitate fluid extraction.

Teeth Adaptations in Mammals:Incisors: In herbivorous mammals, long, flat incisors function like scissors to cut plant material.

Molars: Large, flat molars are used for grinding plant material sideways to increase surface area for digestion.

Diastema: The gap between incisors and molars allows the tongue to move food efficiently towards the molars.

Constant Tooth Growth: Herbivores, like cows and goats, constantly wear down their teeth, leading to continuous growth to keep up with the wear from grinding plant material.

Why Do Herbivores Have Specialized Teeth for Feeding on Plants?

Teeth Structure: The incisors cut the plant material while the molars grind and macerate the plant matter to increase the surface area for enzymatic breakdown.

Constant Tooth Growth: Herbivores like cows and goats wear down their teeth over time from the constant chewing, so their teeth continue to grow to maintain their ability to break down plant material.

What is the Role of Herbivores' Eyes in Avoiding Predators?

Wide Set Eyes: Herbivores often have eyes set far apart on the sides of their heads to increase their visual field. This wide set enables them to spot predators more easily and respond quickly to potential danger.

How Do Hippos' Teeth Differ from Other Herbivores' Teeth?

Teeth Growth: Unlike herbivores that use their teeth for grinding food, hippos have large canine and incisor teeth that grow throughout their lives and can reach up to 50 cm if not worn down. These teeth are used for defense and fighting for mates, rather than for feeding.

Adaptations of Predators for Finding, Catching, and Killing Prey

Acute Senses: Predators have enhanced senses like keen sight, smell, and hearing to track and locate prey.

Speed and Agility: Many predators have adapted for speed, allowing them to chase down prey, as seen in cheetahs.

Camouflage: Some predators, like big cats, use camouflage to blend in with their surroundings and ambush prey.

Sharp Teeth and Claws: Predators often have sharp, pointed teeth or claws for grabbing, holding, and killing prey.

What are the Adaptations of Prey Animals for Resisting Predation?

Defensive Behavior: Prey animals may exhibit behaviors like fleeing, camouflaging, or fighting back to avoid or resist being captured.

Camouflage: Prey like deer or chameleons use camouflage to hide from predators in their environment.

Mimicry: Some prey species use mimicry, resembling dangerous or unpalatable organisms (e.g., viceroy butterflies resembling monarch butterflies).

Speed and Agility: Prey animals like hares and gazelles are adapted for high-speed running to escape predators.

Defensive Structures: Some prey have evolved physical adaptations like spines (e.g., hedgehogs) or venom (e.g., bees) to deter predators.

What Are the Key Adaptations of Plants for Resisting Herbivory?

hysical Defenses: Plants may have thorns, spines, or tough leaves that make it difficult for herbivores to consume them.

Chemical Defenses: Many plants produce toxic chemicals or repellents (e.g., alkaloids, terpenoids) that deter herbivores or make them sick if consumed.

Mimicry and Camouflage: Some plants mimic other organisms or use camouflage to avoid being eaten (e.g., passionflower vines resemble the appearance of unpalatable plants).

Regeneration: Certain plants can regrow parts of their body quickly if damaged by herbivores, making it hard for them to be consumed completely.

What Adaptations Do Plants Have for Harvesting Light?

Leaf Structure: Plants have large, broad leaves to capture as much light as possible for photosynthesis.

Leaf Orientation: Some plants can adjust the orientation of their leaves to face the sun and maximize light absorption.

Chlorophyll: Plants contain chlorophyll, a pigment that absorbs light energy and allows plants to convert it into chemical energy during photosynthesis.

Phototropism: Many plants exhibit phototropism, where they grow towards light sources to optimize their ability to capture light.

How Do Plants Use Chemical Defenses Against Herbivores?

Toxins: Many plants produce toxic compounds (like alkaloids or cyanide), making them unpalatable or harmful if consumed by herbivores.

Chemical Signals: Some plants can release volatile compounds to warn neighboring plants of herbivore attacks, triggering them to activate their own defenses (e.g., tannin production).

How Do Plants Avoid Herbivory Through Chemical Defenses?

Toxic Secondary Compounds: Plants produce secondary compounds (phytochemicals) like terpenes, phenolics, polyketides, and alkaloids. These are toxic to herbivores, making the plant unpalatable or harmful if consumed.

Animal-Plant Warfare: Some herbivores have evolved enzymes to metabolize these compounds. In response, plants may produce non-toxic chemicals that only become toxic after ingestion, further escalating this "arms race."

Phytochemicals in Medicine: Some plant compounds, such as artemisinin (from terpenes) for malaria and paclitaxel (from taxanes) for cancer, are used in modern medicine.

What Are the Four Groups of Phytochemicals?

Terpenes: Used in many plant defenses and modern medicines, like artemisinin for malaria.

Phenolics: Chemical compounds that can deter herbivores or be involved in plant defense.

Polyketides: Bioactive compounds found in plants, some used in traditional and modern medicine.

Alkaloids: Toxic compounds in plants like caffeine, nicotine, or morphine, which can deter herbivores.

What Are Physical Adaptations of Plants to Avoid Herbivory?

Thick, Rigid Leaves: Some plants have tough, rigid leaves that are difficult for herbivores to chew and digest.

Spiny Thorns: Sharp thorns or spines that physically prevent large herbivores from eating the plant.

Microscopic Thorns (Trichomes): These tiny structures deter smaller herbivores like insects. They may stop insects from laying eggs or limit their movement.

Chemical Resins: When combined with thorns, plants may secrete sticky resins or irritating chemicals to further deter herbivores.

How Do Lithops Avoid Predation?

Camouflage: Lithops, also known as living stones, have evolved to look like rocks, making them difficult for herbivores to spot. They grow just above the surface of the ground and avoid detection.

What Is "Animal-Plant Warfare"?

: As plants evolve chemical defenses to deter herbivores, some herbivores evolve the ability to metabolize these chemicals. In turn, some plants produce chemicals that only become toxic after ingestion, escalating the evolutionary "arms race."

Adaptations of Predators to Kill Prey - Physical Strategies

Speed and Agility: Many predators rely on speed (e.g., cheetahs) or agility (e.g., hawks) to capture their prey.

Sharp Claws and Teeth: Predators have specialized teeth and claws for capturing, killing, and breaking down prey.

Keen Senses:Eagles can spot prey from 3 km away.Owls have exceptional hearing to detect even small movements of prey.Pit vipers can sense body heat from nearby prey

Chemical Adaptations of Predators to Kill Prey

Toxins: Many predators, such as fire ants and cone snails, release venoms that can paralyze or kill their prey.Fire Ants: Inject solenopsins, causing a painful burning sensation.Cone Snails: Inject a venom that includes insulin, lowering the prey's sugar levels, which paralyzes them, allowing the predator to consume it.

Behavioral Adaptations of Predators to Catch Prey

Dolphins' Cooperative Hunting: Dolphins use teamwork to create a mud ring around fish, trapping them and making it easier to catch the prey.

Margay's Mimicry: The Margay predator mimics the distress call of a monkey species, attracting the monkey's parent, allowing the Margay to pounce and capture the monkey.

Key Adaptations of Plants to Avoid Herbivory

Toxic Chemicals: Many plants produce toxic chemicals that deter herbivores. These can include alkaloids, terpenes, and other defensive compounds.

Spines and Thorns: Structural defenses like spines or thorns prevent herbivores from consuming the plant.

Microscopic Thorns (Trichomes): Tiny thorns that deter smaller herbivores by making it difficult to move on or lay eggs on the plant.

wax to make it harder to chew and digest

1. How Do Prey Use Camouflage for Protection?

Camouflage: Prey animals have evolved various forms of camouflage to blend into their environment, making it harder for predators to spot them.Zebra Stripes: The stripes of a zebra help it blend into the grasslands, creating confusion for predators, especially in low-light conditions.General Camouflage: Many animals, such as moths, use color patterns or textures that help them blend into the background, providing them with protection from predators.

What Are Physical Adaptations of Prey for Self-Defense?

Speed and Agility: Many prey animals, like gazelles and hares, have evolved to be fast and agile, helping them escape predators quickly.

Spines and Quills: Animals like the hedgehog use sharp spines to deter predators. Hedgehogs can have up to 7000 spines, which make them difficult to attack.

Bright Colors: Some prey species have bright colors or warning patterns (aposematism) that signal to predators that they are toxic or dangerous to eat, such as the poison dart frog or coral snakes.

How Do Prey Use Chemical Defenses?

Noxious Odors: Some prey species release pungent chemicals to deter predators.Skunks: When threatened, skunks spray a strong-smelling liquid containing thiols from their anal glands, which can linger for weeks and repels predators.

Toxic Compounds: Other prey species produce chemicals that can poison or harm predators. For example, milkweed contains toxic compounds that deter herbivores, and monarch butterflies consume these toxins to make themselves unpalatable.

Behavioral Adaptations of Prey

Group Behavior: Many prey species rely on group behavior to increase their chances of survival.Schooling Fish: Species like mackerel work together to form a tight ball or school to confuse or overwhelm predators, making it difficult for them to capture any one individual.Mimicry: Some prey species mimic the appearance or behaviors of more dangerous animals. For example, some non-venomous snakes resemble venomous species to avoid being eaten by predators.

How Do Prey Animals Work Together to Protect Themselves?

Group Defense: Many prey species, such as mackerel fish, work together to form tight groups that confuse predators, making it harder for them to isolate an individual.Mackerel Schooling: Mackerel work together to create a ball, which confuses predators and increases the chances of survival for the group.

How Do Plants Adapt to Harvest Light?

Climbing Plants: Some plants adapt to limited light conditions by climbing other plants to access sunlight.Lianas: These plants have aerial roots that allow them to climb up to 300 meters, reaching the top of trees in rainforests to access light.

Epiphytes: Plants like orchids are epiphytes, meaning they grow on other plants (not in soil) to access sunlight, moisture, and nutrients from their host plants.Strangler Figs: These plants start life as seeds high in tree canopies and send roots down to the ground, eventually enveloping and killing their host tree.

How Do Shade-Tolerant Plants Adapt to Low Light?

Large, Broad Leaves: In the forest understory, where light is limited, plants have evolved to have large, broad leaves to maximize their exposure to light.Thin Leaves: These leaves are often thin, which allows them to capture as much sunlight as possible for photosynthesis in low-light conditions.

What Is the Herb Layer of the Forest?

Herb Layer: The herb layer is the ground-level layer of the forest, made up of plants that are adapted to low light. These plants, such as ferns, grasses, and wildflowers, have evolved to thrive in the shade cast by the taller trees.

How Do Strangler Figs Work?

Strangler Figs: These epiphytic plants start by sending their seeds high up into the canopy. Once established, the fig's roots grow downwards, eventually wrapping around and suffocating their host tree, which they eventually kill. This adaptation allows them to grow without the need for soil, accessing sunlight from above.

Identify which of the following are adaptations of predators that can assist in their hunt and killing of prey.

I. Acute sense of sightII. Bright colour patterns that warn of venomIII. Making sounds of distress

I and III only

Explanation

Predators have very finely tuned sensory systems - an acute sense of sight will assist a predator in locating their prey. The cunning Margay cat is a good mimic and can make a vocalisation that sounds just like a distress call of a pied tamarin monkey. As the parent monkey comes to 'save their offspring', the Margay will pounce and catch its prey.

The bright colour patterns that warn of venom will not assist a predator in hunting or killing its prey - it is an adaptation that assists prey from being eaten as the predator is 'warned' that they will become sick or die if they eat the organism.

Identify which of the following adaptations are used by both predators and prey in their quest for survival.

I. CamouflageII. Anti-venom proteinsIII. Cooperation among members of the species

I, II and III

Explanation

Predators and prey use camouflage to blend in with their environment - this provides hiding and stealth. Both predators and prey may have anti-venom proteins in their bodies that allow them to survive encounters with various venomous organisms that they are either hunting or are escaping from. Predators may cooperate and surround a prey for the kill and prey may join together to appear as a larger organism for survival.

What Is a Fundamental Niche?

The fundamental niche is the full range of environmental and social conditions under which an organism can live and reproduce, without any constraints from other species.

What Is a Realised Niche?

Definition: The realised niche is the portion of the fundamental niche that a species actually occupies, taking into account competition, predation, and other biotic pressures.

Key Feature: The realised niche is always smaller than or equal to the fundamental niche.

How Do Coyotes and Wolves Illustrate Realised Niches?

Fundamental Niche of Coyotes: Coyotes have the potential to occupy a wide range of habitats and resources.

Competition with Wolves: Wolves are more aggressive and outcompete coyotes for food and territory, restricting coyotes to a smaller realised niche.

European Settler Impact: When European settlers reduced wolf populations, the realised niche of coyotes expanded, allowing them to occupy more areas and resources.

What Is the Competitive Exclusion Principle?

Definition: Also known as Gause's Law, it states that two species competing for the same resource cannot coexist indefinitely in the same niche. One will eventually outcompete the other.

Outcome: The less competitive species is either driven to extinction or forced to adapt to a different niche.

What Is an Example of Competitive Exclusion?

Paramecium Experiment:

P. aurelia and P. caudatum: Both species thrive when grown separately.

When Combined: P. aurelia outcompetes P. caudatum, leading to the extinction of P. caudatum.

Reason: P. aurelia is better adapted to the shared environment and outcompetes P. caudatum for nutrients and space.

Can a Realised Niche Change?

Expansion: A realised niche can expand when competitive pressures decrease (e.g., reduced wolf populations allowed coyotes' niche to grow).

Reduction: A realised niche can shrink due to increased competition or the introduction of new species.

Key Graph: Fundamental vs. Realised Niche

Fundamental Niche: Encompasses all abiotic and biotic conditions suitable for the organism.

Realised Niche: Lies within the fundamental niche, constrained by interspecies competition and predation.

Why Is Competitive Exclusion Significant in Ecology?

Biodiversity Regulation: Ensures species do not occupy the same niche for long periods, promoting specialisation and biodiversity.

Adaptation and Evolution: Drives species to adapt to new niches or evolve to reduce competition.

What Is Niche Partitioning?

Definition: Niche partitioning is an ecological process where natural selection allows competing species to adapt and coexist by dividing their niches to reduce direct competition.

What Are the Two Main Types of Niche Partitioning?

Spatial Partitioning: Species use different physical spaces within the same habitat to reduce competition.

Temporal Partitioning: Species use the same habitat at different times to avoid overlap.

What Is an Example of Spatial Partitioning?

MacArthur's Warbler Study (1956):

Species Studied: Five Warbler bird species.

Findings: Each species occupied a different height on coniferous trees.

Other Factors: Different nesting times and varying food preferences helped reduce competition.

What Is an Example of Temporal Partitioning?

Species Studied:Common Spiny Mouse (Acomys cahirinus): Active at night (nocturnal).Golden Spiny Mouse (Acomys russatus): Active during the day (diurnal).

Outcome: Temporal separation allowed them to coexist despite living in the same habitat.

Why Is Niche Partitioning Important?

Reduces Competition: By dividing resources, competing species can survive in the same area.

Encourages Biodiversity: Allows multiple species to thrive in overlapping ecosystems.

How Else Can Species Share Similar Niches?

Dietary Specialisation: Different species may adapt to feed on distinct resources.

Reproductive Timing: Differences in mating or breeding seasons reduce overlap.

Microhabitat Preferences: Use of slightly different areas (e.g., sunny vs. shaded spots) within the same ecosystem.

True or false?

The fundamental niche of an organism will normally be much broader than its realised niche.

True

T

Explanation:

The fundamental niche of an organism will normally be much broader than the realised niche because it does not take into account additional constraints including the presence of other species.

Answer in one word.

According to the competitive exclusion principle, two species cannot continue to occupy the same_____

niche

Identify which of the following factors can influence the realised niche of an organism.

I. Competition with other speciesII. Availability of resourcesIII. Predation pressure

I, II and III

Explanation

The realised niche of an organism is the actual role that it will play in an environment. It takes into account various biotic and abiotic factors that may affect the organism - these include competition with other species, the availability of resources such as food and water and the predation pressure (how many predators exist in the area and how likely the organism will become their prey).

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True or false?

If there are two species living in the same area and they share the same niche, according to the competitive exclusion principle one of the species will die off.

False

F

Explanation:

Although it is very likely that one species will be harmed. The species involved may adapt by a process called niche partitioning. One species may forage at a different time from the other (temporal) or they may limit themselves to only a particular area (spatial within the same environment). If this occurs both species may avoid competition and thrive.

Additionally, two species may temporarily share the same niche.