Chapter 20 (Ecology) Flashcards
Definition of habitat
The place an organism lives
Definition of niche
The role of an organism within its habitat
Definition of species
A group of organisms that can interbreed to produce fertile offspring.
Definition of population
Individuals of the same species living together in a given time period and defined space.
Definition of community
Populations (of different species) that interact with each other in a given time period and defined space.
Definition of autotroph
A species that is able to produce its own food ( usually through photosynthesis)
Definition of producer
An autotroph
Definition of heterotroph
A species that feeds on plant or animal material (cannot make its own food)
Definition of consumer
A heterotroph that feeds on other animals or plants by ingesting them.
Definition of herbivore
Only eats plant material
Definition of carnivore
Only eats animal material
Definition of omnivore
Eats both plant and animal material
Definition of detritivore
A heterotroph that obtains nutrients by ingesting detritus
Definition of Saprotroph
A heterotroph that obtains nutrients by externally digesting dead organisms
Definition of abiotic factor
A non living factor within an ecosystem. ( temp, pH, salinity, light/oxygen levels)
Definition of biotic factor
A living factor within an ecosystem ( predators, prey, parasites, pathogens)
Definition of an ecosystem
A dynamic system consisting of all the interactions between all living organisms in a specific area and all the abiotic factors.
Definition of overfishing
The removal of a species of fish from a body of water at a rate that the species cannot replenish
Factors affecting fish population
- Food availability
- Level of predation
- Diseases and parasites
- Intensity of fishing
Why are fish populations decreasing
- Use of drift nets
- Sonar and satellite detection means fishing is more successful
- Fleet vessels can stay out fishing for longer
- Increased operational radius of the boats
- Fish are processed at sea
Info on fish
- High in protein
- Are ectotherms ( rely on external sources of heat to regulate own body temperatures)
- Hence use less energy to generate heat
- This Increases efficiency of energy transfer in their food chains
Strategies to reduce overfishing
Catch Quotas Minimum catchable size Fishing effort limits No take zones Closed seasons Protected individuals Population seeding
Info on population seeding
Mortality rate in captivity is lower than in the wild, so young fish are raised in captivity then released later to increase survival chances.
Info on protected individuals
Some individuals are protected as they are good breeding animals. If caught, must be released.
Info on closed seasons
A ban on fishing for part of the year (especially during breeding season)
Info on No Take Zones
A complete fishing ban in part of area so a breeding population can develop.
Info on Fishing effort limits
Limits set on size of nets, boats or engines, or number of days fishing to reduce catch.
Info on Minimum catchable size
The size of net controls minimum size of fish that can be caught. (eg, small fish can escape)
Info on Catch quotas
Limit on total weight of fish that can be landed. Rest have to be returned.
Yet, many of them are dead before returned
Definition of sustainable fishing
Removing a controlled number of fish from their populations, so there are sufficient left to reproduce and replenish population, so a similar amount can be fished the following year, and year after, without significantly reducing the population size
Definition of Ruminants
Animals that digest plant material slowly in specialised stomachs, and regurgitate the food to chew again.
Examples of ruminants
Sheep
Cow/Cattle
Goats
Explain why ‘a cow has 4 stomachs’ is incorrect
The stomach is a single organ divided into 4 chambers, linked consecutively, each specialised for their specific function.
What are the 4 chambers in a cow’s stomach.
Rumen
Reticulum
Omasum
Abomasum
Ru Re O A
Are u ready or asleep.
Identify the chambers in a cow’s stomach.
Diagram
Features of the digestive system of a ruminant that allow the efficient digestion of plant material
- Rumen contains micro-organisms that produce cellulase.
- Micro-organisms in rumen and reticulum hydrolyse cellulose and other complex carbohydrates into mono- & di-saccharides.
- Other bacteria convert saccharides into fatty acids.
- Abomasum secretes HCI & proteases to hydrolyse bacterial proteins.
Rumen info
Conditions are anaerobic as micro-organisms in rumen respire anaerobically
Function of the reticulum in a cow?
- fermented grass is passed to reticulum
- it is formed into ‘balls’ called cud.
- cud is regurgitated to mouth to be ground further and reswallowed.
Function of mouth
-Grass is ground by molars + premolars, mixed with saliva, swallowed + passed to rumen.
Function of omasum
- Reswallowed food passed to omasum.
- Has very muscular walls
- When walls contract, it squeezes water out
- Water from cud is reabsorbed .
Function of Abomasum
-Cud passes to abomasum
-Digestion occurs
-Secretion of proteases +HCI
Hydrolysis of proteins into aa.
Function of duodenum
Chyme passes to duodenum
Small soluble nutrients are absorbed
Definition of succession
A natural change in species composition of a community in a given area over a given period of time. Involves recognisable seres
Progresses to a climax community