Populations And Sustainability Flashcards
Define carrying capacity
Max populations size that can be maintained in a habitat over a period of time
Describe a K-strategist curve
1) lag phase= slow growth, few organisms, acclimatising to habitat, rate of reproduction low
2) log phase= rapid growth, resources are plentiful and conditions favourable, rapid population increase
Exponential growth
3) stationary phase= a stable state population size, reached carrying capacity, habitat cannot support a larger population
May fluctuate
What are r-strategists
Boom or bust, extremely high reproductive rate and population growth rate before limiting factor take effect.
Small short lived species (pioneer)
Similar to stationary phase except there is a death phase after
Define limiting factors
Factor that prevents further growth of a population and in some cases cause it to decline
Name 3 abiotic factors
Temperature
pH
Light intensity
Name 3 biotic factors
Competition
Predation
Disease
Define immigration
Movement of individual organisms into a particular area
Define emigration
Movement of individual organisms away from a particular area
How can an introduced species affect other species living in the area
They might be predators
They might stop birds breeding and that reduces their offspring
Means there are less new breeders for the next year
How could a species introduced to an island dramatically increase in number after introduction
Plenty of food and space
There is no predators
Fill a vacant niche
Cannot emigrate
What are density independent factors
Affect populations of all sizes in the same way, examples are natural disasters and fires
What is competition
When organisms compete for limited resources like: light, mates, food, water, minerals and space
What are the two types of competition
Infraspecific
Interspecific
What is interspecific competition
Competition between organisms of different species 😁
What is interspecific competition
Competition between organisms of the same species
Describe interspecific competition
There will be less food and less energy for growth and reproduction
What is competitive exclusion principle
Give an example
Two species are competing for the same food source and the one that uses the resources more effectively will ultimately eliminate the offer
Red and grey squirrels, red squirrel are limited in what they can eat, grey squirrels can eat loads but outcompete the reds by eating all there limited food
Explain the exponential growth in a K strategist curve
Resources are plentiful so population increases in size
Describe the predator prey model
Predators eat prey Prey population decreases Predators compete for limited prey Predator population decreases Fewer prey eaten Prey population increases More food for predators so population increases
How is the predator prey cycle different in the lab rather than the field
The curve in the field has fewer limiting factors
No studies have been done in more diverse environment
Summarise the effect predators may have on the population size of prey
Prey numbers rise and fall- oscillate
Predators help to keep the prey numbers stable
Predation is density- dependent
What are density dependent factors
Factors are dependent on population size
Define conservation
Management of ecosystems sustainably to protect biodiversity
Occurs through, maintaining diversity between species, maintaining habitats and genetic diversity
Define reclamation
Process of restoring ecosystems that have been destroyed
Define preservation
Protecting areas of land unused by humans, examples include nature reservations and marine conservation sites
What are two economic reasons for conservation
Eco-tourism= provides money and jobs
New drugs
Two ecological reasons for conservation
- taking one organism out of the food web affects many others
- photosynthesis regulates climate
Two ethical reasons for conservation
All organisms have the right to life
Human responsibility to provide for future generations
Two social reasons for conservation
- environments allow walking, cycling, climbing - good for health
- natural environments are creative environments
Why is it important that we conserve the rainforest (3)
- preserve biodiversity
- ecotourism
- potential medicine
What is a biological resource
Made by living organisms
Made into products for use by human beings
Define sustainable resource
A renewable resource that is being economically exploited in such a way that it will not diminish or run out
What is the purpose of sustainability (3)
- preserving the environment
- ensuring resources are available for future generations
- allow humans in all societies to live comfortably
How is sustainable management acheived (3)
1) economically viable quantities of timber can be harvested year on year
2) government grants for sustainable management schemes
3) planting to ensure sustainable harvest rate
Why do we use sustainable management
To maintain biodiversity and to allow timber companies to have a secure and sustainable supply of wood
Prevents disruption to nesting sites and prevents soil erosion
Name and explain an example of small scale timber production
Coppicing- deciduous trees:
- the tree is cut close to base in winter
- the following spring shoots rapidly regrow from stool (base)
- 7-20yrs later coppice ready for next harvest
Why may pollarding be used instead of coppicing
When deer species are high
-the trunk gets cut higher so the deer cannot reach the new shoots
Describe rotational coppicing
Divide the wood into sections
Cut a different section each year
Larger trees are not cut down but used for larger timber
Rotational coppicing is good for biodiversity
Different light levels to different habitats👍
Name a negative example of large scale Timber production
Clear-felling:
The removal of all trees from an area chosen for harvesting (logging)
❌reduces soil mineral levels
❌encourages soil erosion
Describe large scale timber production on a sustainable level
1- selective cuttting- removing only the largest trees
2- replace through replanting
3-plant these trees an optimal distance apart to reduce competition
4-manage pests and pathogens
5-ensures areas of the forest remain for indigenous people
What is the planting strategy in sustainable forests
Trees aren’t planted too close together to reduce competition- water, sunlight
Fallen trees are left to rot to create habitat
What is selective cutting
Removing only the largest trees
Replace the trees through replanting (put rides in)
Define ecology
The study of interactions of organisms and their environment
Define ecosystem
A physical area that includes all the organisms and their interactions with the physical environment
Define sustainability
How biological systems remain diverse and productive over time
Explain sustainable fishing
International agreements about the number of fish to be caught
Quotas provide limits on the number of fish caught in a given area
Use nets with different mesh sizes- specific types of fish only are caught
Fish only at certain times of the year- protects breeding season
-fish farming
No que cards on examples like Masai Mara
Soz
