Populations and Sustainability Flashcards
what is population
- group of organisms of the same species that live in the same habitat
- can interbreed and reproduce fertile offspring
what are factors that affect birth rate
- economic conditions
- cultural and religious backgrounds
- social pressures and conditions
- birth control
- political factors
what are factors that affect death rate
- age profile - elderly population
- life expectancy
- food supply
- safe drinking water
- sanitation
- medical care
- natural disasters
- war
what is carrying capacity
- maximum population size that can be maintained in a particular habitat
what are the features of a population growth curve
Lag phase
- low birth rate and low death rate
-birth rate is greater than death rate
- small number of individuals reproduce
Log phase
- increasing number of individuals
- reproduce exponentially
- population has reached its carrying capacity
- population declines until it remains stable
- birth rate = death rate
what are k-strategists
- limiting factors exert more of an effect as the population grows closer to carrying capacity
- gradually levels out
- low reproductive rate, slow development, long life span, large body mass
what are r-strategists
- population size rapidly increases and passes carrying capacity
- not enough resources to survive or reproduce
- build up of waste products
- high reproductive rate, fast development, short life span, small body mass
what are limiting abiotic factors
- light, water, oxygen, humidity, toxic waste
- each species has a different optimum temperature
- Bears hibernate in the winter to increase their survival by conserving energy
- bacteria grow in warm conditions
- Algae needs favourable conditions such as nutrients and lights
what are limiting biotic factors
- food, competition, predators, disease
- some bacteria produce antibiotics
what is immigration
- movement of individuals into an area
what is emigration
- movement of individuals away from an area
what are density independent factors
- has an affect on the whole population
- natural disasters
what is interspecific competition
- competition between species
- as one population size grows the other shrinks
- individuals who are different species compete for resources
what is intraspecific competition
- competition with a species
- individuals who are the same species compete for resources
- availability of resources determine population size
how has interspecific competition been investigated
- two species of paramecium are grown
- when grown together there is a greater competition for food
what is an example of predator-prey relationships
- increase in rabbits means the population of the foxes grow = more food = survive = reproduce
- high number in foxes there is a decline in the rabbit population
- less rabbits = less foxes
- less foxes = less rabbits eaten
what is conservation
- maintaining biodiversity through human action or management
- maintain species diversity/genetic diversity
- sustainable development
what is preservation
- restricting or banning human interference
what is the importance of conservation
Economic
- resources that humans need to survive and provide income
Social
- natural beauty, relaxation, exercise
Ethical
- all organisms have the right to exist and have a role in their ecosystem
- don’t have the right to decide which organisms live/die
- moral obligation to future generations to conserve variety of existing ecosystems
what are the aims of sustainability
- preserve the environment
- ensures resources are available for future generations
- allows humans in all societies to live comfortably
- enables LEDCs to develop through exploiting natural resources
- create a more even balance in the consumption of resources between countries
what is the case study of sustainable development
Andrex
- products are 100% biodegradable and recyclable
- manufacturing - 5% less water used and 0% waste
what is involved in small scale timber production
Coppicing
- tree trunk cut close to the ground
- new shoots grow from the cut surface
- cut and more grow again
Pollarding
- trunk cut higher up so animals cannot eat new shoots
what is involved in large scale timber production
Felling
- felled trees are destroyed and won’t regrow
what is sustainable timber production
- selective cutting - remove largest trees
- replace trees - replant
- plant trees an optimal distance apart to reduce competition
- minimise pests and pathogens
