Studied by 18 people
IB Biology ecology terms
Properties of oxygen
Present as a diatomic molecule, very reactive, is the basis of a majority of biological respiratory processes
Why can’t anaerobic microbes survive in oxygen?
They do not have the required enzymes to detoxify oxygen radicals.
End with -ase
Enzymes
Superoxide dismutase
An enzyme that transforms oxygen radicals into Water and Oxygen
Catalase
An enzyme that breaks down Hydrogen peroxide to Water and Oxygen
H2O2 - H2O + O2
Thermophiles
Organisms that thrive in areas with high temperatures
Aerobic respiration
Respiration that requires oxygen to break down glucose
Anaerobic respiration
Respiration that does not use oxygen as an electron carrier
Thioglycolate broth
Medium of growth for bacterium that is rich in glycolates
Microaerophiles
Aerobes that produce ATP via aerobic respiration / fermentation. Requires between 5 - 15% atmospheric oxygen for growth
Aerotolerant Anaerobe
Produces ATP via anaerobic respiration, and can conduct fermentation. O2 can be present, but is not used for respiration.
Autotrophs
Organisms that produce their own food through photosynthesis or chemosynthesis
Heterotrophs
Organisms that cannot make their own food and rely on other organisms (plants and animals) for nutrition
Oxygen radicals
Molecules containing oxygen that have 1 unpaired valence electron - very reactive
Halophiles
Organisms that thrive in areas with high salinity
Decomposers
Organisms that feed off of dead matter, and help break down organic into their basic chemical compositions
Ecosystem
The culmination of abiotic and biotic factors working in tandem to make a community of living organisms.
Habitat
A geological area with biotic and abiotic factors suited to an organism’s traits
Niche
What the organism’s role in an ecosystem is
Fundamental niche
An organism’s predicted role in an ecosystem - what it ideally would occupy
Realised niche
The role that an organism actually occupies in any given ecosystem / community
Specialist species
Species that are reliant on specific biotic or abiotic factors
Generalist species
Species that have no preference, and are adapted to suit a majority of biotic / abiotic factors.
Adaptive radiation
When a speciation occurs, species from a common ancestor start divulging in variety, and more and more different variants appear.
Range of tolerance
The measurement of intensity in abiotic factors before the species is unable to survive.
Obligate anaerobes
Prokaryotic organisms that are poisoned by O2 and use fermentation / anaerobic respiration
Obligate aerobes
Prokaryotic organisms that require O2 for cellular respiration.
Facultative anarerobes
Uses both aerobic and anaerobic respiration - prefers aerobic respiration.
Types of nutrition
Autotrophic (Photosynthesis, Chemosynthesis), Heterotrophic (Holozoic, Saprotrophic, Parasitic)
Photosynthetic nutrition
Production of ATP through photons from light
Holozoic nutrition
Nutrition taken into the organism, and internally digested
Mixotrophic
Can use either autotrophic or heterotrophic methods of nutrition intake
Saprotrophic
Organisms that externally secrete enzymes to digest food, then take in the broken down molecules - Feeds on organic matter
Competitive exclusion principle - Gause’s law
If two species occupy the same niche, one species will eventually outcompete the other, and the other will die off
Niche partitioning
When two species occupy the same niche, but have evolved to occupy different areas and can co-exist
Spatial niche partitioning
Organisms live in the same niche, but different space
Temporal niche partitioning
Organisms live in the same niche, but are active at different times - different mice are awake during different times of the day.
Species pool
The total amount of species in any given area
Species sorting
The distribution of a species is dependent on the biotic and abiotic factors of an ecosystem
Intraspecies
Inside a species
Interspecies
Between species
What information do niche relationships provide?
Community structure: Total community niche space, Niche overlap, and Niche breadth of individual species
Characteristics of high species diversity
Lots of species due to weaker competition and lots of resources.
Ecological equivalents
Species that live in different geographic locations but have the same ecological niche
Species exclusion
When two species coexist, one species is always better adapted, and will lead to the other one dying out
How do species control competitors?
Avoidance or Predation
What happens in separate niches?
Species do not interfere with each other
What happens in slightly overlapping niches?
Niche partitioning and competition
What happens in slightly overlapping niches after niche partitioning?
Less competition, speciation into two separate niches
What happens when niches overlap too much?
Gause’s law / Competitive exclusion principle occurs - one species dies out.
Outcomes of competitive exclusion
One species goes extinct, and/or niche is divided, and species divulges further.
Total exclusion
When species A has a bigger niche than species B - leads to A being generalist and B being specialist
Competitive release
Species expands their niches in response to removal of a competitor
Detrivores
Organisms that feed on detritus - organic matter like soil.
Osmotrophy
Taking up dissolved substances
Phagotrophic
Engulfing bacteria and other cells as particulate prey
Auxotrophic
Algae that are unable to synthesize essential components such as the vitamins of the B12 complex / fatty acids and must import them
Types of herbivores
Grazers, Browsers, Granivores, Frugivores, Nectivores, Phloem feeders
Grazers
Herbivores that feed on leaf tissue
Browsers
Herbivores that feed on wood tissue
Granivores
Herbivores that feed on seeds
Frugivores
Herbivores that feed on fruit
Nectivores
Herbivores that feed on nectar
Phloem feeders
Herbivores that feed on sap
Plant apparency
Plants avoid herbivory by decreasing apparency in spatial / temporal refuges
Endophytes
Symbiotic plant prokaryotes
Elemental defenses
Inorganic chemical defences that must be concentrated from environment
Positive tropism
Movement of a plant towards a stimulus
Negative tropism
Movement of a plant away from a stimulus
Geotropism
Growth in response to gravity
Phototropism
Growht in response to light
Thigmotropism
Growth in response to touch
Thermotropism
Growth in response to heat
Hydrotropism
Growth in response to water
Chemotropism
Growth in response to chemical stimuli
Epiphytes
Commensalistic plants that live on trees
Shade tolerant / avoiding plants
Plants that can / ‘t survive in shade
Note 
Flashcard (83)