4.1 Species and Ecosystems Flashcards
What is a species?
A species is a group of organisms that can potentially interbreed to produce fertile, viable offspring
can members from one species reproduce with another species?
Members of a single species are unable to produce fertile, viable offspring with members from a different species
What happens when two different species interbreed?
When two different species do produce offspring by cross-breeding, these hybrids are reproductively sterile (e.g. liger, mule)
What is a population?
A population is a group of organisms of the same species that are living in the same area at the same time
Can organisms that live in different regions still be considered species?
Organisms that live in different regions (i.e. different populations) are reproductively isolated and unlikely to interbreed, however are classified as the same species if interbreeding is functionally possible
What is a community?
A group of populations living together and interacting with each other within a given area
What is a habitat?
The environment in which a species normally lives, or the location of a living organism
What is an ecosystem?
A community and its abiotic environment (i.e. habitat)
What is ecology?
The study of the relationship between living organisms, or between living organisms and their environment
What ae the 3 ways organisms can obtain chemical energy?
autotrophs
heterotrophs
mixotrophs
What are autotrophs?
Synthesises its own organic molecules from simple inorganic substances (e.g. CO2, nitrates)
Where do autotrophs gain energy from?
Energy for this process is derived from sunlight (photosynthesis) or via the oxidation of inorganic molecules (chemosynthesis)
What is the term used to refer to autotrophs?
Because autotrophs synthesise their own organic molecules they are commonly referred to as producers
What are heterotrophs?
Obtains organic molecules from other organisms (either living / recently killed or their non-living remains and detritus)
What are heterotrophs referred to as?
Because heterotrophs cannot produce their own organic molecules and obtain it from other sources, they are called consumers
What are mixotrophs?
Certain unicellular organisms may on occasion use both forms of nutrition, depending on resource availability
What is an example of a mixotroph?
Euglena gracilis possess chlorophyll for photosynthesis (autotrophic) but may also feed on detritus (heterotrophic)
What are the 3 types of heterotrophs?
consumers
detritivores
saprotrophs
What are consumers?
Consumers ingest organic molecules from living or recently killed organisms
What are detritivores?
Detritivores ingest organic molecules found in the non-living remnants of organisms (e.g. detritus, humus)
What are saprotrophs?
Saprotrophs release digestive enzymes and then absorb the external products of digestion (decomposers)
In what two ways do autotrophs derive energy for the synthesis of organic molecules from simple inorganic substances?
Most autotrophs derive the energy for this process from sunlight (via photosynthesis)
Some may derive the needed energy from the oxidation of inorganic chemicals (chemosynthesis)
Where do autotrophs gain the inorganic substances from?
Autotrophs obtain the simple inorganic substances required for this process from the abiotic environment
What are examples of inorganic substances that autotrophs use?
These nutrients – including carbon, nitrogen, hydrogen, oxygen and phosphorus – are obtained from the air, water and soil
Can heterotrophs also use simple organic substances from the environment?
YES
Heterotrophs also may obtain some simple inorganic substances from the environment, but principally obtain their carbon and nitrogen from the organic molecules produced by autotrophs
How do heterotrophs obtain nutrients?
Heterotrophs obtain organic molecules from other organisms via different feeding mechanisms and different food sources
How can heterotrophs be differentially classified from autotrophs?
Consequently, heterotrophs can be differentially classified according to their feeding pattern
What are consumers?
Consumers are heterotrophs that feed on living organisms by ingestion
What are herbivores?
Herbivores are consumers that feed principally on plant matter (e.g. cows, sheep, rabbits)
What are carnivores?
Carnivores are consumers that feed principally on animal matter (e.g. crocodiles, wolves, tigers)
What are omnivores?
Omnivores are consumers that have a principle diet composed of both plant and animal matter (e.g. pandas, humans)
What are scavengers?
Scavengers are a type of consumer that principally feed on dead and decaying carcasses rather than hunting live prey
What are examples of scavengers?
Examples of scavengers include hyenas, vultures and carrion birds (such as crows)
What are detrivores, how do they gain their nutrients?
Detritivores are a type of heterotroph that obtains nutrients from non-living organic sources, such as detritus and humus
What is detritus?
Detritus is dead, particulate organic matter – such as decaying organic material and fecal matter
What does humus refer to?
Humus is the term given specifically to the decaying leaf litter intermixed within the topsoil
What are examples of detrivores?
Detritivores include dung beetles, earthworms, woodlice, snails and crabs
What are saprotrophs and what do they feed off of?
Saprotrophs live on (or in) non-living organic matter, secrete digestive enzymes into it and absorbing the products of digestion
How are saprotrophs different from other heterotrophs?
Unlike other types of heterotrophs, saprotrophs do not ingest food but use enzymatic secretion to facilitate external digestion
What is another term for saprotrophs and why?
Because saprotrophs facilitate the breakdown of dead organic material, they are commonly referred to as decomposers
What are examples of saprotrophs?
Examples of saprotrophs include bacteria and fungi
What are nutrients and examples?
Nutrients refer to the material required by an organism, and include elements such as carbon, nitrogen and phosphorus
Why is nutrient cycling necessary?
The supply of inorganic nutrients on Earth is finite – new elements cannot simply be created and so are in limited supply
How are inorganic nutrients recycled if they are finite?
Hence chemical elements are constantly recycled after they are used
How do autotrophs obtain inorganic nutrients?
Autotrophs obtain inorganic nutrients from the air, water and soil and convert them into organic compounds
How are inorganic compounds obtained by heterotrophs? What are the compounds used for?
Heterotrophs ingest these organic compounds (autotrophs) and use them for growth and respiration, releasing inorganic byproducts
How are nutrients recycled once organisms die?
When organisms die, saprotrophs decompose the remains and free inorganic materials into the soil
What does the return of inorganic nutrients to the soil ensure?
The return of inorganic nutrients to the soil ensures the continual supply of raw materials for the autotrophs
