IB HL Biology Topic B Form and Function (incomplete v2)

Habitat

The environment in which a species normally lives, or the location of a living organism

Species

A group of organisms that can potentially interbreed to produce fertile, viable offspring

Population

A group of organisms of the same species that are living in the same area at the same time

Community

A group of populations living together and interacting with each other within a given area

Ecosystem

A community and its abiotic environment (i.e. habitat)

Ecology

The study of the relationship between living organisms, or between living organisms and their environment

Xerophyte

A plant adapted and able to survive in an environment with little available water or moisture

Limiting Factor

A component of an ecosystem which limits the distribution or numbers of a population, defining optimal survival conditions

Biotic Factors

Interactions between organisms, either intraspecific (within species) or interspecific (between species)

Abiotic Factors

Environmental conditions such as light, temperature, salinity, rainfall, wind velocity, soil pH, etc.

Temperature

Plants can only survive within a narrow range of temperatures to which they are adapted.

Water Availability

Water is needed for photosynthetic processes and maintaining cell turgor.

Light Availability

Light is essential for photosynthesis, with low-growing plants possessing darker green leaves for optimal light conversion.

Salinity

Most plants have low soil salinity tolerance, with high salinity being toxic and hindering water uptake.

Territory

Territorial boundaries affect an animal's capacity for various activities like attracting mates, foraging, and avoiding predators.

Food Availability

The availability of food directly influences population size and distribution of animals.

Law of Tolerance

Populations have optimal survival conditions within critical minimal and maximal thresholds, as proposed by Victor Ernest Shelford.

Optimal Zone

Central portion of the bell-shaped curve representing conditions favoring maximal reproductive success and survivability.

Zones of Stress

Regions flanking the optimal zone where organisms can survive but with reduced reproductive success.

Zones of Intolerance

Outermost regions where organisms cannot survive, representing extremes of the limiting factor.

Glycophytes

Plant species not salt-tolerant, easily damaged by high salinity.

Halophytes

Salt-tolerant plant species that may become stressed in freshwater environments.

Quadrats

Rectangular frames of known dimensions used to establish population densities.

Transects

Straight lines along an abiotic gradient for recording population data to determine patterns.

Kite Graph

Represents changes in species distribution along a transect, with the width of each 'kite' indicating abundance.

Coral Reef Formation

Coral species form reefs impacted by oceanic temperature and pH changes, requiring shallow, clear water and specific temperature ranges.

Reef-building coral optimal growth range

Typical range in shallow, temperate waters between 20 - 30ºC

Biome

Geographical area with specific climate sustaining plant and animal community

Biosphere

Total area where all living things are found

Tropical Rainforest characteristics

Hot climate, high precipitation, high biodiversity, epiphytes

Taiga characteristics

Cold, coniferous forests, low precipitation, little species variation

Desert characteristics

Extreme temperature conditions, low precipitation, xerophytes

Whittaker's biome classification

Classified biomes based on yearly temperatures and rainfall

Temperate Grassland

Moderate temperatures, dominant grass vegetation

Mediterranean biome

Moderate temperatures, dry summers, woody shrubs

Tundra characteristics

Freezing temperatures, low precipitation, low-growing vegetation

Mountain Ranges

High altitude areas with low temperatures and rapid weather changes

Hot Desert adaptations

Expire, evade, endure methods for survival in extreme conditions

Tropical Rainforest structure

Complex ecosystem with ground to canopy layers, diverse adaptations

Ecological Niche

Functional role of an organism in its environment

Obligate aerobe

Requires oxygen for respiration

Obligate anaerobe

Respires only in absence of oxygen, poisoned by oxygen

Facultative anaerobe

Can switch between aerobic and anaerobic respiration

Autotrophs

Organisms that produce their own organic molecules using either light energy or energy derived from the oxidation of chemicals

Heterotrophs

Organisms that obtain organic molecules from other organisms through ingestion, detritus consumption, or absorption of external products of digestion

Consumers

Heterotrophs that ingest organic molecules from living or recently killed organisms

Detritivores

Heterotrophs that ingest organic molecules found in non-living remnants of organisms

Saprotrophs

Heterotrophs that release digestive enzymes to absorb external products of digestion, commonly referred to as decomposers

Photosynthesis

Process by which autotrophs synthesize organic molecules from simple inorganic substances using sunlight or chemosynthesis

Holozoic Nutrition

Type of nutrition in animals where organic molecules are obtained from other organisms through ingestion

Mixotrophic Nutrition

Nutrition in certain protists that involves both autotrophic and heterotrophic modes, depending on resource availability

Symbiotic Nutrition

Nutritional relationship between different species living in close physical association, often mutually beneficial

Archaea

One of the three domains of life, metabolically diverse and including various photosynthetic, chemosynthetic, and heterotrophic organisms

Extremophiles

Organisms, including some Archaea, that thrive in extreme environmental conditions

Dentition

The arrangement of teeth in a species

Organelles

Discrete subunits of a cell adapted to perform specific functions

types of organelles

nucleus, mitochondria, endoplasmic reticulum (rough and smooth), golgi apparatus, vesicles, chloroplasts, centrosome

nucleus

double membraned w/ pores, stores genetic material, has nucleolus responsible for ribosome assembly, controls transcription

mitochondria

responsible for ATP production (via aerobic cell respiration), highly folded inner membrane to increases SA:VOL ratio

endoplasmic reticulum

membranous network that synthesises and transports materials, smooth synthesises lipids, rough synthesises proteins via ribosomes

golgi apparatus

assembly of folded membranes → material secretion, material is sorted, stored, modified, and exported via vesicles (exocytosis)

vesicles

membranous containers involved in transport and storage

peroxisomes

type of vesicle, involved in oxidation of lipids and digestion of toxic metabolites

lysosomes

responsible for the break down of cellular waste and pathogenic debris

vacuoles

comparatively larger containers that store excess fluid and regulate pH

chloroplasts

responsible for photosynthesis (conversion of light energy into chemical energy), use photosynthetic pigment chlorophyll to absorb and utilise light energy

centrosome

function as microtubule-organising centres composed of paired centrioles, contribute towards cell division in animal cells

Plasma membrane

Semi-permeable barrier enclosing cell contents, controlling internal conditions

Ribosomes

Cellular structures responsible for protein synthesis

Eukaryotes

Cells with a distinct nucleus and membrane-bound organelles

Transcription

Process converting DNA instructions into RNA transcripts (mRNA), controlled by nucleus

Translation

Synthesis of proteins from RNA transcripts by ribosomes, occurs in cytoplasm

Post-transcriptional modification

Processes stabilizing mRNA and removing non-coding sequences following transcription but before translation

Compartmentalising cytoplasm

Separating cytoplasm into sections with membrane-bound organelles for specific functions

autophagy

hydrolytic enzymes freely digesting the contents of a cell (stopping is an advantage of compartmentalising cytoplasm)

Lysosomes

Organelles containing hydrolytic enzymes for digesting cellular debris

Phagocytic vacuoles

vesicles containing enzymes for engulfed pathogenic materials digestion

Stem Cells

Unspecialised cells with self-renewal and potency qualities

Totipotent

Stem cells capable of forming any cell type and developing into new organisms

Pluripotent

Stem cells capable of forming any cell type arising from the three germ layers

Multipotent

Stem cells capable of forming a number of closely related cell types

Stem cell niches

Sites within the body maintaining adult stem cells for future proliferation and differentiation

Haemopoietic stem cells

Located in bone marrow, giving rise to different types of blood cells (erythrocytes, leucocytes, thrombocytes)

epidermal stem cells

involved in cyclic bouts of hair growth, skin innervation, vascularisation, wound repair

Differentiation

Process during development whereby newly formed cells become more specialised and distinct

Embryonic Development

Process of unspecialised zygote dividing and developing into a mass of specialised cells

Morphogens

Gene regulating chemicals impacting embryonic development, concentration determines degree of differentiation

Cell Size

must be able to balance cell volume and surface area for optimal metabolism and material exchange

Red blood cells

Highly specialized cells with small size for efficient gas exchange

Phospholipid bilayer

Semi-permeable barrier formed by phospholipids enclosing cell contents

Membrane Protein

Proteins embedded in or attached to the cell membrane, with functions including junctions, enzymes, transport, recognition, anchorage, and transduction

Integral Proteins

Permanently embedded within the cell membrane, with hydrophobic regions associating with the lipid bilayer and polar amino acids facing the aqueous solutions

Peripheral Proteins

proteins that are temporarily associated with one side of a membrane, either attached to integral proteins, linked to the polar heads of the bilayer, or held in place by the cytoskeleton or extracellular matrix

Glycosylation

The process of attaching carbohydrate chains to phospholipids or membrane proteins, located on the extracellular side and playing important roles in adhesion, recognition, and maintaining structural integrity

Fluid Mosaic Model

Representation of cell membranes as a fluid mosaic, with phospholipids arranged in a bilayer, embedded proteins, and cholesterol interspersed in animal cell membranes

Passive Transport

Movement of material along a concentration gradient without the expenditure of energy, including simple diffusion, osmosis, and facilitated diffusion

Active Transport

Movement of materials against a concentration gradient requiring energy expenditure, including primary (using ATP) and secondary (coupled to another molecule moving down an electrochemical gradient) transport

Diffusion

Net movement of molecules from a region of high concentration to a region of low concentration, influenced by factors such as temperature, molecular size, and steepness of gradient

Junctions

where Membrane proteins serve to connect and join cells together

Enzymes

Membrane proteins fixing to membranes to localize metabolic pathways