Ecology Flashcards
Factors for environment
Abiotic factors
Biotic factors
Abiotic factors
The non-living factors of an ecosystem
e.g. rocks, water, air, sunlight, nutrients (soil), weather patterns, temperature, soil, humidity and salt concentration
Biotic factors
The living components of an ecosystem
Can grow, reproduce, respire, undergo complex chemical reactions, have cells, and can move.
e.g. plants, animals, fungi, bacteria and virus*
Levels of organisation (small to big)
Species
Population
Habitat
Community
Ecosystem
Biome
What is a species
A species is a group of genetically similar living organisms that are able to interbreed and produce fertile offspring.
What is a population
Population are groups of individuals that belong to the same species and live in the same area
What is a habitat
Habitat is the area in which species normally lives
What is a community
Community includes populations of different species living and interacting with each other in the same environment.
What is an ecosystem
Ecosystem is a community of living organisms interacting with each other and with the abiotic factors.
What is a biome
Biome is a group of ecosystems that have the same climate and similar dominant communities.
What is a fertile offspring
Fertile offsprings are those which can in turn interbreed and pass on their genes to another generation.
2 types of speciation
Allopatric speciation
Geographic barriers
Sympatric speciation
Reproductive isolation
Explain allopatric speciation
This occurs when a geographical barrier physically isolates populations of an ancestral species.
•The two populations begin to evolve separately as a result of cumulative mutation, genetic drift and natural selection.
•Eventually the two populations reach a degree of genetic divergence whereby they can no longer interbreed (speciation).
Explain behaviour differences
behavioral changes, such as those involved in mating, foraging, and migration, can generate reproductive barriers between populations. (e.g. mating rituals)
Explain niche partitioning
the process by which natural selection drives competing species into different patterns of resource use or different niches
Types of niche partitioning
Resource partitioning
Intraspecific competition
Interspecific competition
Explain resource partitioning
when species divide a niche to avoid competition for resources.
Explain intraspecific competition
competition between individuals of the same species.
Explain interspecific competiton
competition between species.
explain sympatric speciation
Sympatric speciation is divergence of species within thesame geographical location. (no locational barrier)
Sympatric speciation may result from the reproductive isolation of two populations as a result of genetic abnormalities
Typically, a chromosomal error may arise which prevents successful reproduction with any organism lacking the same error
what does auto mean
self
what does trophe mean
nutrition
explain autotrophs
make its own food
synthesize organic molecules from simple inorganic nutrients
Inorganic nutrients are from the abiotic environment (soil, pH, water, etc.)
what are producers
can make its own food
forms the base of the food web
holds the energy to be transferred up the food chain
what does hetero mean
other
what are heterotrophs
are organisms that obtain organic nutrients from other organisms.
The method & type of food intake determines the heterotroph type.
Consumers, parasites, detritivores and saprotrophs
what are consumers
they cannot make food
examples of consumers
Prey: the hunted
Predator: the hunter
Herbivore: eats plants
Carnivore: eats animals
Omnivore: eats both plants and animals
what are parasites
Considered to be heterotrophs & consumers
Live on or inside other living organisms (called hosts) and obtain food from them
e.g. tapeworms, hookworms
how do consumers ingest food
they ingest food through their mouths
how do bacteria feed
Bacteria feed in different ways. Heterotrophic bacteria, or heterotrophs, get their energy through consumingorganic carbon. Most absorb dead organic material, such as decomposing flesh.
what are decomposers
Breaks down dead organisms
Examples: bacteria, maggots, fungi, worms
Complete the circle of life by returning nutrients to the soil
e.g.(detritivores/saprotrophs)
what are detritivores
organism that consumes non-living organic matter
consumes dead leaves, faeces, and carcasses
e.g. earthworms, woodlice, dung beetles
There are bottom feeders in rivers, lakes and oceans that are detritivores.
what are saprotrophs
Heterotrophs that obtains their food from dead organisms by external digestion
Live on or in non-living organic matter, secreting digestive enzymes and absorbing the products of digestion
Helps in decaying of dead organic matter
e.g. fungi and bacteria
what are mixotrophs
A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a single trophic mode on the continuum from complete autotrophy at one end to heterotrophy at the other.
It is estimated that mixotrophs comprise more than half of all microscopic plankton.
bacteria
some autotrophic and some heterotrophic
protoctista
some autotrophic and some heterotropic
fungi
heterotrophic
plantae
mostly autotrophic
animalia
heterotrophic
what is biodiversity
Number of different varieties and types of organisms in an ecosystem.
examples of symbiotic relationship
mutualism
commensalism
parasitism
what is mutualism
where both organisms benefit from the relationship
examples
oxpeckers and large mammals
clownfish and anemones
what is commensalism
where one organism benefits and the other is unaffected
the commensal organism obtains food, shelter, locomotion, or support
examples
milkweed and monarch butterfly
sharks and remora fish
what is parasitism
when one organism benefits and the other is harmed
examples
bedbugs
flea
tapeworm
examples of predation relationship
predatory-prey
competition
what is predator-prey interaction
the interactions between two species where one species is the hunted food source for the other
the organism that feeds is called the predator and the organism that is fed upon is the prey
examples
Wolves and elk in Yellowstone National Park on willow trees
Brown Bears and Salmon
Lions and zebras
what is competition
Two individuals are competing for the same resource
i.e. Foxes and coyotes both feed on rabbits
types of ecosystem
natural
artificial
terrestrial
aquatic
what are scavengers
they are animals that can feed on the remains of another organism
Example
Vulture, beetle, flies, ants
what is a natural ecosystem
it exists in nature and is not man-made
examples
forest, desert, ocean, lake, river
what is an artificial ecosystem
it is made by man
examples
park, pond, aquarium, zoo
what is a terrestrial ecosystem
The ecosystem is found on land and can be natural or artificial
what is an aquatic ecosystem
it is an ecosystem that can be found in water, it can be natural or artificial
examples
pond, ocean, lake, river
what are the problems with food chains
Food chains are very good at showing simple relationships.
But they don’t show…
More than one producers & Herbivores
Herbivores that eat many producers
Omnivores (both plants and animals)
what is sustainability
living organisms like plants, animals, bacteria, insects and other living things that can interact and reproduce indefinitely
For ex: Long-lived and healthy wetlands and forests are examples of sustainable biological systems.
what is biodiversity
Number of different varieties and types of organisms in an ecosystem.
High levels of biodiversity are usually associated with a healthy, sustainable environment.
what is a food chain
It is a way to describe how energy is stored and transferred from one living thing to another. A food chain starts with a producer and ends with a consumer. It is used to show simple feeding relationships. The arrows show the direction in which food energy is moving.
what are food chains used for
Food chains are channels for the one-way flow of a tiny part of the sun’s high-quality energy captured by photosynthesis, through the living components of ecosystems, and into the environment as low-quality heat.
Food chains are also pathways for the recycling of nutrients from producers, consumers and decomposers back to producers.
what are food webs
A connected feeding relationship for an ecosystem
Bottom-up links with many possible paths
Arrows point in direction of energy flow
what do trophic levels show
how an organism gains its energy
an organisms feeding position on the food chain.
what does trophic mean in greek
to feed
different types of ecological pyramids
Pyramids of energy
Pyramids of numbers
Pyramids of biomass
what are ecological pyramids
A representation of energy, numbers, or biomass (the mass of living organisms in a given area) relationships in ecosystems.
what is a energy pyramid
It shows energy loss and transfer between trophic levels
the size of each layer represents the amount of energy available at that trophic level.
cannot be turned upside down
pyramid of energy flow
Shows the energy found in the bodies of the organisms and the transfer of chemical energy from level to level
this energy transfer is very inefficient
A pyramid of energy flow can never be inverted.
how is energy lost in the pyramid
Plantsuseenergytocarryoutlifeprocessessuchas growthandnutrient transportation (about 30%).
Energyislosttotheenvironmentaswasteheat energy.
Energyisusedbyconsumersforlifeprocesses.
Remainingenergyisusedbydecomposerswhen organismsdie.
Not all of the organism gets consumed or can be digested.
60 % of the energy consumed is passed out as waste.
If a fox eats a rabbit, it does not eat the fur or the bones.
Humans cannot digest the cellulose (fibre) part of foods
how is the pyramid of energy measured
Measured as the energy flow per unit area per unit time
J m-2 y-1 or J/m • y
𝐽/(𝑚”•” 𝑦)
what is a pyramid of numbers
A pyramid of numbers shows the shear population size for each organism or level.
characteristics of a pyramid of numbers
at higher trophic levels, the number of consumers get smaller
less energy to support another level
so there are a lot of producers and progressively less and less at higher trophic levels
problem of pyramid of numbers
organisms with a high biomass can turn a pyramid of numbers upside down
Answer: build a pyramid of biomass
what is biomass
Biomass is a measure of the total dry mass of living organisms
what do pyramid of biomass do better
Pyramids of biomass are better indicators of the chemical energy available at each level.
how is biomass measured
Area delimited and sampled
Standard area and sufficient sample size needed
Organisms identified and sorted by trophic level
Even underground structures/organisms needed
It may be necessary to separate tissues from inorganic shells (e.g. molluscs)
Tissues of organisms massed (weighed)
= Fresh mass
Tissues dried to constant mass (80-100°C)
= Dry mass
Removes water leaving organic matter
Destructive sampling
why is rate of production a problem
As the life cycle of some organisms is faster their turn over is faster
Sample at any one time and you find less of the organisms with a fast turn over (e.g. phytoplankton)
Energy transfer needs to be measured over a whole growing season.
