B4.2 Ecological Niches

SL biology topic

What is the definition of an ecological niche

refers to the role an organism plays in a habitat. A species’ niche includes the type of food a species eats, where it lives, where it reproduces, and its interactions with other species (e.g. predation or competition).​

What are the components of ecological niches

• Habitat

• Activity patterns of the animal/organism

• Resource that the animal obtains from the environment

• the interactions that occur with other species in the region.

what is the definition of resource partitioning?

When a species show adaptation to the ecological niche which they ocupy to avoid competition they occupy only their area.

What are Niche Generalists?

Thrive in a wide variety of environmental conditions and can make use of a variety of different resources. They are adaptable and flexible.​

• Maybe search up an example of this.

  • racoons - elaborate

What are Niche specialists?

Adapted to thrive in a narrow range of environmental conditions and often rely on a specific type of resource. They have highly specialized needs

• Maybe search up an example of this

  • Panda - Elaborate

Define aerobic

Refers to the process or activates that require the presence of oxygen.

Microorganisms can be categorised according to their mechanism of respiration name the three:

Obligate anaerobes: Respire anaerobically and can only grow in the absence of oxygen.​

Facultative anaerobes: Facultative anaerobes can respire anaerobically or aerobically depending on oxygen availability.​

Obligate aerobes: Obligate aerobes only respire aerobically and cannot survive in the absence of oxygen.​

Explain what is occurring in this image and refer to the answer in the previous slide.

What is an example of obligate aerobes and what is their function.

• Microbacterium tuberculosis is an obligate anerobe that causes diseases tuberculosis

• Function:

  • They are organisms that use oxygen to metabolise substances like sugar or fats to produce ATP through aerobic cellular respiration.

What is an example of obligate anaerobes and what is their function.

• Obligate aerobes are found in oxygen-free environments such as intestinal tracts of animals.

• Function:

  • organisms that produce ATP via anaerobic cellular respiration or fermentation. They die by atmospheric levels of oxygen.

What is an example of Facultative anaerobes and what is their function.

• Yeast is a facultative anaerobe. Yeast will use fermentation over aerobic respiration (even if there is plenty of oxygen) whenever the sugar supply is bountiful.

• Function:

  • Facultative anaerobes produce ATP via aerobic cellular respiration, anaerobic respiration and/or fermentation.​

    Since they can survive in many different environments, facultative anaerobes can easily adapt to changing conditions.​

• Most life threatening pathogenic bacteria are facultative anaerobes.

What is a Winogradsky column?

• A simple device to demonstrate the concept of niche

• The device is creates an aerobic/anaerobic gradient as well as a sulfide gradient. ​

  These two gradients promote the growth of different microorganisms that appear as different color bands within the column.​

What is the definition of mode of nutrition

The method by which an organism obtains its energy and nutrients

Which two categories can mode of nutrition fall into. and explain the category.

• Autotrophic: Organisms that produce their own food.

• Heterotrophic: Organisms that have to eat/ obtain food from other organisms.

Make a model about the three different modes of nutrition providing examples and explanation

What is the process of photosynthesis?

There are different types of photosynthesis, depending on the species, but in general, the following are true: ​

• The energy source for photosynthetic organisms is light. ​

• The carbon source for photosynthetic organisms is usually carbon dioxide (CO2 - dissolved in water for aquatic organisms).​

What is the definition of holozoic nutrition

Holozoic nutrition is when an organism consumes a variety of organic material, which then undergoes a series of metabolic processes such as digestion, absorption, and assimilation. ​

What is the definition of absorption in digestion

The process of taking in substances into the bloodstream. This can happen across tissues and organs through diffusion and osmosis.

Whats the definition of Assimilation

Occurs when absorbed products are finally delivered to the specific cell to be used.

Describe the Holozoic nutrition process of an organism using

Define mixotrophic nutrition

Certain unicellular organisms may on occasion use both autotrophic and heterotrophic forms of nutrition, depending on resource availability.

• examples are carnivorous.

What is an example of mixotrophic protist

• Euglena is a well-known freshwater example of a protist that is both autotrophic and heterotrophic.

• When there is no light Euglena ingests organic material from its environment. (Via phagocytosis)

What are the two different classifications of Mixotrophs

Obligate Mixotrophs - Obligated to use both autotrophic and heterotrophic means of nutrition to survive.​

Facultative Mixotrophs - Can switch between autotrophic and heterotrophic nutrition, but do not depend on it for survival.

What are examples of obligate and Facultative mixotrophs

Obligate: Dinophysis is a genus that requires photosynthetic products from its prey (usually cryptomonads, a type of algae), making it an obligate mixotroph.​

Facultative: Carnivorous plants (pitcher plants, venus fly traps) are a common example. ​

Define a decomposer

A decomposer is an organism that breaks down and recycles dead or decaying organic material.​

• essential of nutrient cycling to be reused for other organisms and environment.

What are the two types of decomposers

• Detritivores: Ingest non-living organic mattere e.g: earthworms,woodlice

• Saprotrophs: Feeds on non-living organic matter by secreting digestive and absorbing the products. e.g : fungi and bacteria

Compare and contrast the location of digestion in saprotrophs and detritivore animals.

Detritivores: Internal digestion​

Detritivores ingest organic molecules found in the non-living remnants of dead organisms Digestion is internal (inside the body).​

Saprotrophs: External Digestion​

Saprotrophs release digestive enzymes and then absorb the products (decomposers). Digestion is therefore external. ​

Explain why all saprotrophs are decomposers but not all decomposers are saprotrophs

• All saprotrophs are considered decomposers because they directly engage in the chemical breakdown of dead organic matter, which is a fundamental aspect of the decomposition process.​

• Some decomposers (like many detritivores) do not break down organic matter chemically using secreted enzymes. Instead, they contribute to decomposition through physical means or through internal digestion processes.​

List the three domains of life and explain what they are.

Eubacteria – prokaryotic cells lacking a nucleus and consist of the common pathogenic forms (e.g. E. coli, S. aureus, etc.)

Archaea – aka “the extremophiles” - prokaryotic cells that live in extreme conditions (e.g. methanogens, thermophiles, etc.)​

Eukarya – eukaryotic organisms that contain a membrane- bound nucleus (includes protist, plants, fungi and animals)​

What (outline) the characteristics of archaea

• Unique phospholipid structures in their cell membranes

• Cell walls are made of a different molecule than those of bacteria.​

• Mostly don’t interact with plants and animals (as much as bacteria) ​

• Many are extremophiles, preferring extreme hot or cold, extreme salinity, etc.​

Elaborate on the unique phospholipid structures in the archaea cell membrane

The phospholipids that comprise archaea cell membranes have branched fatty acids with unique type of bonding to the glycerol backbone*.​

Elaborate on why archaea done interact with plants and animals

With few exceptions, archaea are not present in the human microbiota, and none are currently known to be associated with infectious diseases in humans, animals, plants, or microorganisms.​

Elaborate on how many of the archaea are extremophiles

Many archaea are extremophiles, preferring extreme hot or cold, extreme salinity, or other conditions that are hostile to most other forms of life on earth.​

How can archaea obtain energy and what is their many carbon source

• Nearly all archaea are autotrophs using co2 as a carbon source

• The can obtain energy from

  • Photoautotrophs - light

  • Chemoautotrophs - oxidation of inorganic materials

Define photoautotrophs archaea and how they work

• they can photosynthesis but different from the classic

  • In archaea, pigments other than chlorophyll are used​

  • In archaea, photosynthesis does not generate oxygen​

  • In archaea, rather than an electron transport chain, light-activated ion pumps generate ion gradients.​

Define chemoautotrophs archaea and how they work

• Isolated in different extreme habitats

• Chemoautotrophs can use inorganic energy sources sich as hyrdrogen, sulfide ferrous iron, molecular hydrogen and ammonia to produce energy

• Maybe the form of the formation of LUCA

Outline the role of methanogenic archaea in the transformation of organic material into methane​

• Methanogens are archaea microorganisms that oxidize simple carbon compounds (e.g. CO2)* and produce methane (CH4) as a metabolic byproduct: ​

  • CO2 + 4H2 → CH4 + 2H2O

Whats the process of turning organic material into methane called?

Methanogenesis

Meth - methane

genesis - origin

What are some anaerobic conditions where methanogens maybe found.

• Wetlands (e.g. swamps and marshes)​

• Marine sediments (e.g. in the mud of lake beds)​

• Digestive tract of ruminant animals (e.g. cows, sheep, goats)​

Define Dentition

Dentition refers to the features and arrangement of the teeth in a particular species or individual.​

Teeth reflect adaptations to various functions (cutting, chewing, and grinding food, etc). ​

Outline the morphological adaptation of the chimpanzees teeth to accommodate with its diet

Chimpanzees have an omnivorous diet, consuming fruits, nuts, leaves, insects, and occasionally hunting smaller mammals. ​

Their teeth include large incisors and canines used for biting and defense, and molars with complex cusp patterns for crushing and grinding a wide range of foods.

Outline the morphological adaptation of the Gorillas teeth to accommodate with its diet

Gorillas primarily have a herbivorous diet, consuming stems, bamboo shoots, leaves, and some fruit.

Gorilla dentition features large, flat molars with a thicker enamel, adapted for grinding tough plant material.​

Gorillas have large canines, which are more related to social dominance and display than their diet.​

Outline the morphological adaptation of the Humans teeth to accommodate with its diet

Humans have a mixed dentition that supports an omnivorous diet, including a variety of plant and animal foods.

The reduced size of human canines compared to other hominids and the development of molars for grinding both fibrous plant material and meat reflects an adaptation to a diverse diet.

Define the term Hominidae

The family Hominidae (also known as great apes) includes humans, chimpanzees, gorillas, and orangutans.​

Each species exhibits variations in dentition that reflect their diverse diets, ranging from omnivorous to herbivorous.​

List extinct and extant representatives of the Hominidae family of primates

• Gorillini shows a path of evolution that emphasizes physical strength and herbivory.​

• Hominini, on the other hand, includes humans and their closest relatives (chimpanzees and bonobos). ​

  This lineage is marked by cognitive development, social complexity, and a range of dietary and ecological adaptations.​

Can could scientist figure out the diet of extinct Hominids

• Through observation which made theories

• These theorise allowed the diet of extinct hominids to be deduced. (deductive reasoning)

State Advantages and disadvantages of using digital models of skulls

Advantages

• Preserving delicate fossils providing cost-efficient, long-term preservation solutions.​

• Enhancing accessibility for global collaboration.​

• Enabling detailed manipulation and analysis.​

• Reconstructing incomplete specimens.​

• Effective educational tools. ​

Disadvantages

• Loss of microscopic details.​

• Reliance on specialised technology, and risks of misrepresentation.​

• Ethical concerns over ownership and data sharing. ​

​

Deduce the diet of an organism given skull features​ (Homo floresiensis)

Homo floresiensis had relatively small teeth (even for their small body size). ​

Their dental pattern suggests they could process a variety of foods, similar to modern humans, but with perhaps a greater emphasis on tough, fibrous plant materials or hard objects (based on wear patterns of fossils).

Deduce the diet of an organism given skull features​ (Paranthropus robustus)

Paranthropus robustus had large molars, thick enamel, and robust jaw muscles, indicated by the sagittal crest* atop their skull. ​

These features suggest a diet primarily composed of tough, fibrous plant materials that require heavy chewing, such as roots, nuts, and seeds.​

Deduce the diet of an organism given skull features​ (Australopithecus Afraensis)

A. afarensis was a generalist omnivore with a transitional dentition suitable for a mixed diet, indicating a flexible lifestyle in diverse environments.​

Teeth are adapted for both cutting and grinding, have thick enamel indicating adaptation to a diet that included hard or abrasive foods like nuts and seeds.​

Summary of the dental comparison between all three organisms mentioned

What are leaf-eating animals called?

• Leaf-eating animals known as Folivores exhibit a range of adaptations that enable them to eat plants

Outline the physiological, morphological and/or behavioral adaptations of herbivores for feeding on plants​ (Pierce-sucking mouthparts)

• Some insects have a long, slender proboscis or stylet that can pierce through plant tissues to reach the phloem or xylem sap.

• They inject saliva containing the enzyme pectinase into the plant, which can break down the polysaccharide pectin, which holds together the cell walls facilitating easier access to nutrients

• Example: Aphids

Outline the physiological, morphological and/or behavioral adaptations of herbivores for feeding on plants​ (Chewing mouthparts)

Other insects are equipped with strong, sharp chewing mouthparts called mandibles. ​

These are capable of cutting, tearing, and grinding leaf material and can vary in shape/size, depending on the dietary requirements of the insect.​

How do cow and sheep chew and digest food?

• The only have lower incisors with dental pads and specialised back teeth ot grind down grass.

• Their digestive systems are specifically adapted to digesting plant matter. ​

  Bacteria and archea living in the rumen help to break down cellulose. ​

What have some plants adapted to prevent predators from eating them. (mechanical deterrents)

• Cacti have sharp spines to deter herbivores that might attempt to eat their succulent stems​

• Nettles have tiny hairs that contain toxins which irritate the skin​

​

• Thick bark prevents insects such as aphids from piercing plant stems​

​

• Many tiny hairs on leaves may make it more difficult for insects to bite into/pierce plant tissues​

What have some plants adapted to prevent predators from eating them. (Chemical deterrents)

• Herbivores can also produce a number of phytotoxins made from secondary compounds (primary compounds are the ones used by the plant in metabolism). ​

​

• Foxgloves produce a toxic compound known as digitalis which can affect the heartbeat of humans and animals​

Examples:

• Alkaliods: nicotine,caffine,morphine

• Terpeniods: methanol, taxol used in cancer treatment

• Phenolics: capsaicin, tannins ( bitter tasting but used to age wine)

Outline the chemical, physical and/or behavioral adaptations of predators for finding, catching and killing prey

• Finding prey

  • Enhanced Sensory Organs: ​

    Highly developed senses to detect prey (e.g., owls have extraordinary hearing, and sharks can detect minute electrical fields generated by their prey.)​

  • Camouflage: Some predators use camouflage to blend into their environment, making it easier to approach prey unnoticed.

• Catching prey

  • Speed and ability: Predators have evolved to be faster and more agile than their prey.-

• Killing prey

  • Stealth and Ambush: Stalking with stealth to get close before launching a rapid attack.

  • ​Venom: Some predators, like snakes and spiders, use venom to immobilize or kill their prey.​

    ​

Outline the chemical, physical and/or behavioral adaptations of prey animals for resisting predation​

• Avoiding detection

  • Camouflage ​

    Prey animals often have coloring that helps them blend into their environment, such as the leaf-like appearance of many insects.

• Escape and evasion

  • Protective Features: Some animals have spines (like porcupines) or hard shells (like turtles) that make them difficult or unappealing for predators to handle.​

• Mimicry

  • Some harmless species evolve to look like (mimic) other poisonous ones, deterring predators. ​

Describe examples of adaptations for harvesting light*​ (meaning how do plants gain light)

• Height

  • Trees (and some shrubs) compete for sunlight by growing taller. The tallest trees form the canopy layer, receiving the most sunlight. ​

• Leaf surface area

  • Large leaves increase the area available for photosynthesis, allowing plants to absorb more sunlight*.​

• Shade tolerance

  • Understory Plants are shade- tolerant plants (e.g., many shrubs and ferns) have adaptations that allow them to photosynthesize efficiently in low-light conditions found under the canopy. ​

  • These plants often have larger, thinner leaves compared to those exposed to full sunlight, maximizing the surface area for light absorption.​

• Lianas (climbing vines)

  • Lianas are woody vines* that climb up the trunks of other trees to reach the sunlight in the upper canopy. This strategy allows them to access the light available at the top of the forest without investing energy into developing a robust trunk to support themselves. ​

• epiphytes

  • Epiphytes grow on the surfaces of other plants, particularly on branches and trunks in the canopy, without rooting in the soil.

  • Orchids and bromeliads are classic examples, capturing light and moisture from the air and debris around them. (Pictured is Tillandsia, a type of “Air Plant”.)​

Distinguish between fundamental and realized niches​

• A fundamental niche is the entire set of conditions under which an organism can survive and reproduce (where it could live).​

  • Example: In a rocky shore environment, the Chthamalus barnacle can potentially occupy the entire rocky shore (if in isolation)​

• A realised niche is the set of conditions used by an organism after including interactions with other species (where it does live).​

  • Example: In a rocky shore environment, the Chthamalus barnacle only occupies regions where the Semibalanus barnacle is absent

Explain why two species cannot survive indefinitely in the same habitat if their niches are identical

If two distinct species share an identical niche, there will be interspecific competition for available space and resources.​

Competition results in the fitness of one being lowered by the presence of the other.​

Explain competitive exclusion as a factor that can limit the distribution of a species in an ecosystem

ompetitive exclusion principle – one species uses the resources more efficiently, driving the other species to local extinction.​

State that organisms that can adapt to extreme niches encounter less competition and predation​

n resource partitioning, both species alter their use of the habitat to divide resources between them (i.e. niche separation).​

Examples of resource partitioning include: ​

• Spatial (species might occupy different areas of the same habitat)​

• Temporal (The same space at different times)​

• Dietary (One species adapts to different types of food)

• This is used as competitive exclusion does not consider the effect of ecological conditions