Ecosystems/ Environmental factors
What is an ecosystem?
Organisms living in a discrete region/ community interacting with each other and their non-living surroundings.
In an ecosystem, temperature, rainfall, and sunlight affect how much energy producers can capture. What type of factors are these?
Abiotic Factors
Plants are called this because they produce their own food either through photosynthesis or chemosynthesis.
Autotrophs
What is the Formula used to calculate diversity in ecosystems?
Simpsons Diversity Index
What is Photosynthesis? (whats the process?)
A process that allows plants to use sunlight to turn carbon dioxide into glucose and oxygen.
The place where an organism lives, like a forest, desert, or reef, is called this.
Habitat
In a mangrove ecosystem, crabs dig burrows in muddy soil, trees grow in salty water, and fish shelter among the roots. Which factors are abiotic and which are biotic?
Abiotic: Soil, water
Biotic: Crabs, mangrove trees and fish
Each step in a food chain (or organisms position in a food chain) is called a what?
Trophic Level
What is the difference between species richness and evenness?
Species richness is the number of species present.
Species evenness: How similar the population size of those species are.
Water evaporates from PLANT LEAVES to the atmosphere in this process adding to the amount of water vapour in the air, what is this called?
Transpiration
What are the two broad categories that habitats can be divided into?
Terrestrial and Aquatic
What is a keystone species?
An organism that has an unusually large affect on its ecosystem, even if its population is small.
Only 10% of energy from one trophic level is passed onto the next. What happens to the remaining energy?
Lost as heat, movement or waste
A forest that contains many different types of birds, mammals, and insects is said to have high what?
Species Diversity
When plants and animals die, decomposers break them down and release what into the atmosphere?
Carbon Dioxide
A tide pool on the rocky shore which shelters crabs, small fish, and seaweed. What is this smaller, specialised area within the forest ecosystem called?
Microhabitat
(localised part of a a general habitat)
Why are keystone species important for biodiversity.
Maintain ecosystem balance by:
Controlling populations and supporting food webs.
In aquatic ecosystems, why do algae and phytoplankton form the base of most food webs?
Because they are producers that capture sunlight energy and convert it into food for other organisms.
Ecologists use quadrats and transects to study biodiversity. What is the main difference between the two methods?
Quadrats are square sampling frames placed randomly or systematically to measure coverage and abundance (fixed), while transects are lines along an environmental gradient at fixed intervals to measure the presents or absence of a species (changes in diversity).
Percolation (Infiltration)
What is the difference between a realised niche and fundamental niche?
Realised Niche: Actual range of conditions a species occupies/ actual use of resources by a species.
Fundamental Niche: The full range of environmental conditions a species could occupy without competition or predators.
In a kelp forest ecosystems, sea otters eat sea urchins. Fisherman hunted sea otters to the point of extinction (because they believed they were eating all the fish). The sea urchin population increased very quickly and ate up all the kelp. Identify the keystone species:
Sea Otters
Explain why food chains rarely have more than 4 or 5 trophic levels.
Energy decreases at each level, leaving too little energy to support additional levels.
Explain why high biodiversity makes an ecosystem more resilient to change?
more species and genetic variety provide stability, alternative food sources, and greater ability to adapt to environmental changes.
In the nitrogen cycle, nitrifying bacteria turn ammonium into nitrites and then nitrates. Why are nitrates important for plants?
They are a usable form of nitrogen that plants absorb to make proteins and DNA.