IB MYP 4-5 Biology-Habitat- Study Notes - New Syllabus
IB MYP 4-5 Biology-Habitat- Study Notes – New syllabus
IB MYP 4-5 Biology-Habitat- Study Notes – IB MYP 4-5 Biology – per latest IB MYP Biology Syllabus.
Key Concepts:
- Biotic vs. abiotic factors
- Ecological niches
- Adaptation to extreme environments (e.g., deserts, deep sea)
Organisms and Their Habitat
What is a Habitat?
A habitat is the natural environment where an organism lives, grows, and reproduces. It provides food, shelter, water, and suitable conditions for survival.
Examples of habitats include:
- Forest
- Desert
- Freshwater pond
- Marine ocean
- Grassland
1. Abiotic Factors (Non-living Components)
Abiotic factors are the physical and chemical aspects of an environment that affect organisms.
- Temperature: Affects enzyme activity and metabolism.
- Light: Drives photosynthesis and regulates biological rhythms.
- Water availability: Essential for hydration and cell function.
- Soil type: Influences plant growth based on nutrients and structure.
- pH levels: Controls microbial activity and nutrient absorption.
- Salinity: Vital in aquatic ecosystems.
- Air composition: Oxygen and carbon dioxide impact respiration and photosynthesis.
- Topography: Land features affect drainage, sunlight, and microclimates.
2. Biotic Factors (Living Components)
Biotic factors include all living organisms in a habitat and their interactions.
- Producers: Plants and algae that make food via photosynthesis.
- Consumers: Animals that eat plants or other animals (herbivores, carnivores, omnivores).
- Decomposers: Bacteria and fungi that break down dead matter.
- Competitors: Organisms competing for the same resources.
- Predators and prey: Control population dynamics.
- Mutualists: Species that benefit each other (e.g., bees and flowers).
Biotic vs Abiotic: Comparison Table
| Feature | Biotic Factors | Abiotic Factors |
|---|---|---|
| Nature | Living | Non-living |
| Examples | Plants, animals, fungi, bacteria | Light, temperature, water, soil |
| Influence | Competition, predation, symbiosis | Climate, pH, minerals, salinity |
| Interaction | Direct (feeding, mating) | Indirect (influence conditions) |
Summary:
- A habitat includes both biotic and abiotic components.
- Abiotic factors set environmental limits for survival.
- Biotic factors involve all living interactions and organisms.
- Both are crucial to shaping ecosystems and maintaining balance.
Ecological Niches
What is an Ecological Niche?
An ecological niche is the role and position an organism occupies in its environment how it gets its food, where it lives, how it reproduces, and how it interacts with other organisms and abiotic factors.
Key Aspects of a Niche
- Habitat: Where the organism lives
- Feeding relationships: What it eats and what eats it
- Activity patterns: Day vs. night activity (diurnal/nocturnal)
- Reproductive behavior: Breeding season, strategy, mating rituals
- Interactions: Competition, predation, mutualism, parasitism
- Abiotic tolerances: Temperature, water needs, pH, salinity, etc.
Types of Niches
1. Fundamental Niche
The full range of environmental conditions and resources an organism could theoretically use without competition or other biotic limits.
2. Realized Niche
The actual range of conditions and resources used by the organism in the presence of competitors, predators, and parasites.
Example: Oak Tree vs. Woodpecker
- Oak Tree: Uses sunlight, water, and minerals to perform photosynthesis. Provides shelter for other species.
- Woodpecker: Lives in tree trunks, feeds on insects in bark, controls insect population.
Competitive Exclusion Principle
Two species cannot occupy the exact same niche in the same environment for long. One will eventually outcompete the other, leading to:
- Extinction of one species
- Niche differentiation (resource partitioning)
Summary:
- Niche: Role of an organism including food, behavior, and abiotic interactions
- Fundamental niche: Potential range
- Realized niche: Actual range used
- Competitive exclusion: No two species can share the exact same niche forever
Adaptation to Extreme Environments
Adaptation refers to structural, physiological, or behavioral traits that enhance an organism’s ability to survive and reproduce in a specific environment. In extreme environments, these adaptations are vital for basic survival.
1. Adaptations in Desert Environments
Deserts are hot and dry habitats with intense sunlight and scarce water. Organisms here must be efficient in water conservation and heat management.
Plant Adaptations
- Thick cuticle: Reduces water loss through evaporation
- Reduced leaves or spines: Minimizes surface area for transpiration
- Sunken stomata: Traps moisture in a humid pocket
- CAM photosynthesis: Stomata open at night to reduce water loss
Animal Adaptations
- Nocturnal behavior: Activity limited to cooler nighttime hours
- Burrowing lifestyle: Staying underground to avoid heat
- Water-efficient metabolism: Produces concentrated urine or dry feces
- Thin body structures: Facilitates heat loss
- Fat storage in one area: For example, camels store fat in their humps to reduce body insulation
2. Adaptations in Deep Sea Environments
The deep sea is a dark, high-pressure, cold environment with minimal food availability. Organisms have adapted to survive under these extreme conditions.
Animal Adaptations
- Bioluminescence: Light production for communication or hunting
- Slow metabolism: Conserves energy due to limited food supply
- Large eyes or no eyes: Enhanced vision or reliance on other senses
- Pressure-resistant bodies: Flexible proteins and membranes resist crushing forces
- Expandable jaws and stomachs: Allow the consumption of large, infrequent prey
Comparison Table: Desert vs Deep Sea Adaptations
| Feature | Desert Adaptation | Deep Sea Adaptation |
|---|---|---|
| Water availability | Water conservation mechanisms | Water is not limiting, but food is scarce |
| Temperature | Tolerance to high heat and fluctuations | Adapted to cold and stable temperatures |
| Light availability | Intense sunlight | Complete darkness |
| Structural features | Spines, thick cuticle, burrowing limbs | Bioluminescent organs, large mouths, soft bodies |
| Behavioral traits | Nocturnality, dormancy | Slow movement, passive hunting |
Summary:
- Organisms adapt structurally, behaviorally, and physiologically to survive extreme environments.
- Desert adaptations focus on water conservation and temperature regulation.
- Deep sea adaptations address darkness, high pressure, and limited food.
- Each ecosystem presents unique challenges that shape the organisms living there.