Topic 4 Flashcards
What is Ecology?
The study of relationships between living organisms and between organisms and their environment.
What is a population?
A group of organisms of the same species living in the same area at the same time.
What is an ecosystem?
A community and its abiotic environment.
What is abiotic?
Non-living-anything that was never living.
F.e. plastic chairs
‘Biotic ‘=living, or once-living thing.
F.e. fruits, vegetables, paper, toilet paper (product of the living thing)
What is a community?
A group of populations living and interacting with each other in an area.
What is a habitat?
The environment in which a species normally lives (the location of a living organism)
What is a species?
A group of organisms that can interbreed to produce fertile offspring
In what case is it often impossible for species to breed?
When the species are not closely related, it is often impossible for individuals of the different species to breed.
What happens when members of two closely related species do interbreed?
The offspring they produce, the hybrids, will be sterile e.g. mules.
Organisms of the same species separated geographically or temporally are…
unlikely to breed.
Organisms of the same species separated geographically or temporally are unlikely to breed, though the ability to do so remains. The separated organisms are regarded as being members of different populations.
A lion is dependent on the availability of prey species, such as zebra and antelope. What does this show?
All organisms are dependent on interactions with members of other species for survival.
Communities also include plants and microbes and hence often involve thousands of species.
Define autotrophs.
Autotrophs convert CO2 (from the atmosphere or dissolved in water) into organic compounds.
Plants initially synthesise sugars (f.e. glucose) which are then converted into other organic compounds such as:
- complex carbohydrates, such as starch, cellulose
- lipids
- amino acids
Where are the inorganic nutrient compounds, such as water, CO2, nitrates, phosphorus and oxygen obtained?
From the abiotic environment, whether it be the soil, air or water.
What are chemoautotrophs?
Although most autotrophs fix carbon by photosynthesis., some are chemoautotrophs and fix carbon by utilising the energy in the bonds of inorganic compounds such as hydrogen sulfide.
Why do all organisms require organic molecules, such as amino acids?
To carry out the functions of life, f.e. metabolism, growth, and reproduction
What are autotrophs known as?
Autotrophs synthesise their own organic molecules, therefore, they are known as producers
What are heterotrophs?
Heterotrophs obtain their organic molecules from other organisms.
Plants, animals, and algae that use a combination of different modes of nutrition are called…
Mixotrophs
What are heterotrophs that ingest other organisms to obtain their organic molecules called?
They are known as consumers.
What do herbivores feed on?
Herbivores feed on producers.
E.g. deer, zebra, aphids
What do omnivores feed on?
Omnivores feed on a combination of both producers and consumers.
E.g. chimpanzee, mouse
What do carnivores feed on?
Carnivores feed on other consumers.
E.g. lions, snakes, ladybirds
What do scavengers feed on?
Scavengers are specialised carnivores that feed mostly on dead and decaying animals
E.g. hyenas, vultures, crows
What are trophic levels?
An organism’s place on the food chain, food web, or ecological pyramid
What is Trophic Level 1?
Producer
What is Trophic Level 2?
Primary consumer
What is Trophic Level 3?
Secondary consumer
What is Trophic Level 4?
Tertiary consumer
What are detritivores?
A type of heterotroph that obtain nutrients by consuming non-living organic sources, such as detritus and humus.
E.g. dung beetles, earthworms, woodlice, crabs
What is humus?
Decaying leaf litter mixed with the soil
What is detritus?
Dead, particulate organic matter. This includes decaying organic material and faecal matter.
What are Saprotrophs?
Saprotrophs live on, or in, non-living organic matter. They secrete digestive enzymes onto the organic matter and absorb the products of digestion.
E.g. bacteria, fungi
Are saprotrophs consumers?
No. Unlike most heterotrophs, they are not consumers, as they do not ingest food: digestion is external as enzymes are secreted.
What are Saprotrophs also referred to as?
As they facilitate the breakdown of organic material, they are also referred to as decomposers.
How do we know if something is alive?
1. RINGER R-Reproduction I-Irritability N-Nutrition G-Growth E-Excretion R-Respiration
2. MRS GREN M-Movement R-Respiration S-Sensitivity G-Growth R-Reproduction E-Excretion N-Nutrition
