4.1 Species, Communities and Ecosystems Flashcards
What is a biotic factor?
Any Material that has a significant biochemical function.
Examples are prey, soil bacteria, bugs, plants…
What is an abiotic factor?
The physical environment of an ecosystem is known as an abiotic factor.
Examples are rain, soil type, temperature, oxygen level…
What is a species?
a group of organisms that can interbreed and produce fertile offspring
Example: humans
What is a habitat?
the environment in which a species normally lives or the location of a living organism
Example: tree canopy
What is a population?
- Members of a species may be reproductively isolated in separate populations.
- a group of organisms of the same species who live in the same area at the same time
What is a community?
populations of different species living and interacting with each other in an area
Example: forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria
What is an ecosystem?
a community and its abiotic environment
Exp: Pond/lake
What is ecology?
the study of relationships between living organisms and between organisms and their environment
What is a biome?
Biomes are divisions of the biosphere and are devided by their climate and topography. Rainfall and temperature are the two most important factors that determine the appearance of a biome
What is an autotroph?
an organism that make their own carbon compounds from simple inorganic substance from the abiotic environment.
What is a heterotroph?
an organism that obtains carbon compounds from other organisms
What are three types of heterotrophs?
Consumer, Detritivore, Saprotroph
What is a consumer?
heterotrophs that feed on living organisms by ingestion. (ie. an organism that eats other living organism)
What is a detritivore?
heterotrophs that obtain organic nutrients from detritus by internal digestion. (ie. an organism that eats dead organic matter and digests them internally)
What is a saprotroph?
heterotrophs that obtain organic nutrients from dead
organisms by external digestion. (ie. an organism that secrets digestive enzymes into dead stuffs and then suck up the juice)
Example of a saprotroph?
Example fungi, mould, mushroom
Example of detritivore?
Example earthworms
What is a food chain?
A linear link from producer to consumer.
General form:
A →B → C → D indicates that A is being “eaten” by B, B eaten by C and so on (that is, the arrow indicates the direction of energy flow).
Each food chain should include a producer and consumers, but not decomposers.
What is a food web?
A bunch of food chains interconnecting with each other
What is quadrat sampling?
Quadrat is just a square thing used to sample the plants in the area (not for animals). The goal of using quadrat is so that ecologist can survey different area the same way in order to make comparison between 2 or more areas.
What is a mesocosm?
Mescosm is a small area where parts of the natural environment are kept under controlled conditions.
Why do we use mesocosm?
Advantages:
- Able to control variables and thus gives the opportunity to measure the degree of stability or extent of change in the community, and to investigate a precise impact of a disturbing factor
Disadvantages:
- Unrealistic
What does a t-Test do?
It compares two means/averages
What is Chi-square used for?
it is used to compare if what you observed is different from what you expected
Compare the way in which autotrophic, heterotrophic and saprotrophic organisms obtain energy.
autotrophs use an external / non-organic energy source
(reject statements suggestion that energy is made)
(some) autotrophs use light / (some) autotrophs use photosynthesis
(some) autotrophs use inorganic chemical reactions / (some) autotrophs use chemosynthesis
heterotrophs obtain energy from other organisms
heterotrophs (usually) ingest food / consume food
saprotrophs obtain energy from non-living matter / dead organisms
saprotrophs digest organic matter extracellularly
Describe a method for measuring the size of a population of plants using quadrats.
random positions for the quadrats
use of random numbers fro co-ordinates / other randomisation procedure
many repeats / quadrats
size of quadrat depends on size / density of plants
count number of plants in each quadrat
find mean number of plants per quadrat
multiply number per unit area by total area to obtain total population
Describe what is meant by a food chain using an example with four named organisms.
(4)
food chains describe the feeding relationships between species;
Exp:
Carrot plant → Eastern Cottontail Rabbit → Red fox → Golden Eagle
Why does an ecosystem have the potential to be sustainable over a long period?
- continual flow of energy
- nutrients are recycled
- removal of toxins
- conservations allows balance
