Unit 2.1-2.3 (KOGNITY ONLY) Flashcards
Ecology
The study of interactions between organisms and the environment in which they live
Organism measures
How varied they are (diversity), where they are located (distribution), what they are (species), how many there are (population), and how they interact and adapt
An ecosystem is made up of
Biotic (living) and abiotic (non-living) components
All species have two binomial names, there
Part 1 is the genus, part 2 is specific to the species
Species each
Have a habitat and a niche even if they all live together
The niche of a species
What they do for a living
Carrying capacity
Max number of species that it can support at a given time
Ecosystem
Community of interdependent organisms and the physical element they interact with
Biotic component
Anything living and interactions between living components. This includes all the organisms (plants and animals), anything they consume or that consumes them, and human influences
Biotic component examples
Producers, consumers, decomposers, interactions between them
Producers
Plants that convert energy into matter
Consumers
Animals that eat plants or other animals
Decomposers
Organisms that breakdown waste into component parts for reuse
Interactions between living components
Predation, herbivory, parasitism, mutualism, disease, competition
Species
A group of organisms with common characteristics that can interbreed to produce fertile offspring
Population
A group of individuals of the same species living in the same area at the same time
Population example:
The Eurasian red squirrel - 23 subspecies across Europe and Siberia
The development of subspecies
The further apart the population, the less likely of interbreeding
Population determination factors
Births and immigration (growth), deaths and emigration (decline)
Population growth
Birth + immigration > deaths and emigration
Population decline
Births + immigration < deaths and emigration
Population dynamic equilibrium
Births + immigration = death and emigration
Abiotic components
Non living things - Influence living elements and operate as limiting factors - Biotic elements interact with abiotic elements
Abiotic component examples
Sunlight, pH, temperatures, salinity, precipitation
Ectotherms such as reptiles….
Rely on the environment to regulate their body temperature so this is a large factor of their distribution
All organisms have a temperature range….
Which they can live, and if the temperature deviates too much they will be stressed and may die
Water temperature influences….
The amount of oxygen the water contains and is vital to aquatic life
Sunlight and solar energy
The base of most food chains, creates photosythesis, enables plants to transform light energy into chemical energy
Sunlight has seasonal fluctuations, this affects….
Life cycles of plants and animals, length of growing season, mating cycles and more
Sunlight in aquatic systems
Water absorbs light, the deeper into the water, the less light available, so photosynthesis is not possible 200m down. There is zonation 1000m down where there is no light
Water in an ecosystem….
Water arrives to an ecosystem as precipitation, groundwater, flow, or overland flow. It is an ingredient in photosynthesis and the medium in which life’s processes take place
Organisms and water
Different organisms have different levels of tolerance to lack of water. Eg: deserts. Animals can become weak and confused and will die if water is scarce for too long.
PH in an ecosystem
All organisms have a tolerance range in which they thrive. If the PH doesn’t remain balanced, the ecosystem will break down (eg: freshwater, soil microbes)
Salinity in an ecosystem
Like all abiotic factors, organisms have a range of tolerance to salinity. (Impact on soil which causes agricultural issues if too high) aquatic ecosystems are sensitive to changes
Habitat
Environment around an organism which is where they live, it provides physical and biological resources for that organism. It may not be a distinct location (parasite and host’s body)
Physical habitat characteristics:
Soil, moisture, temperature, sunlight
Biological environment of habitats”
Food, mate, predators
Niche
A set of abiotic and biotic convictions and resources to which an organism or population responds. The smallest unit of the habitat, how an organism fits into an ecosystem, where it lives, what it does, how it survives and reproduces
Example of a niche (red-eyed tree frog)
Carnivore, eater of moths, flies, crickets, and smaller frogs to prevent overpopulation. Provider of food for bats, birds, spiders, and snakes
No two species have the same….
Niche at the same time or location (if many species live together, they still have different needs) eg: diet
Fundamental niche
The full range of conditions and resources in which as species could survives and reproduce (tolerance range for abiotic factor’s in an organism’s environment)
Realised Niche
The actual conditions and resources in which a species exists due to biotic interactions (the part of the fundamental niche occupied by the species)
Limiting factors
Resources in the environment that limit the growth, abundance, and distributions of organisms in an ecosystem
Density dependent limiting factors
Affect the population when it reaches a certain density. They include competition, disease, parasitism and predation - they tend to be biotic factors. Disease spreads rapidly when there are many organisms for it to spread to
Density independent limiting factors
Control population no matter the density. Include sunlight, temperature, water, and natural disasters. High or low, organisms still need a particular temperature, amount of sunlight and water
Changes in population in response to abiotic or biotic factors
Can be represented as J and S shaped curves
J shaped curve shows:
Exponential population growth under ideal conditions with plenty of resources and limited competition. Population grows until environmental resistance take effect (organisms using all resources making population crash). Organisms following this will show great fluctuation and a “boom and bust” in pop. numbers
S shaped curve
Likely if resources are limited, limiting factors. Exponential growth only posible for a short period of time as resources are depleted as population grows. When it slows it will plateau off
Interaction among organisms….
Relate population size and impact the balance of the food web
Predation
One organism (predator) hunts and kills another (the prey) in order to provide it with the energy for survival and reproduction
Predation impact
Only beneficial to the predator, however, both populations are kept in balance
Herbivory
Consumption of plant material by an animal (herbivores)
Herbivory impact
Plants have defence mechanisms which makes eating painful for herbivores, some are toxic to the herbivore. So animals tend to add variation to their diet, or build up a tolerance
Parasitism
An organism (the parasite) takes nutrients from other organisms (the host)
Parasites
May live outside the host, or inside the host. It is not beneficial for it to kill the host, as it loses it’s habitat. As the population increases, the host will die. Parasite populations outnumber the host because the parasites are significantly smaller
Mutualism
Where two organisms of different species exist in a mutually beneficial relationship. Sometimes if the species of one increases, so will the other
Mutualism is a form of
“Symbiosis” which is a form of living together and there are a range of relationships created by it, amongst different organisms. It is a key process of an ecosystem (eg: 50% of terrestrial plants rely on fingí to absorb inorganic compounds from their roots)
Examples of mutualism
Sea anemones and clown fish - the fish provide food, anemones’ tentacles keep the fish away from predators. Oxpecker bird eats ticks off of zebras, buffaloes and rhinos, so the oxpecker can eat and the mammal is rid of the ticks
Disease
Departure from the normal state of functioning of any living organism, which can effect the whole body or just part of it. Signs and symptoms may be the result of environmental events, genetic defects or a combination. In serious cases, it can kill a population
Disease examples:
Ebola kills endangered gorillas and chimps, a major effect on already deleted populations. Anthrax killed 90% of Herbivores in Zimbabwe’s Malilangwe wildlife reserve (Tasmanian devil tumour)
Disease Impacts
Disease in normal populations can be devastating but catastrophic in endangered