Chapter 1 Populations Flashcards
What is a population?
A group of individuals of the same species in the same habitat
What is an ecosystem?
Area made up of all abiotic and biotic factors
What is a community?
Groups of different species in one area
What is a habitat
A place where communities or populations live
What is a ecological niche?
All things needed for a organism to survive and reproduce, how it fits into an environment
What are abiotic factors?
Non living
For example: volume of rainfall, concentration of co2 or sunlight
Describe biotic factors and give examples?
Living things
For example: predation and competition
What does abundance mean?
To count the number of individuals of one species in a specific area
What are the two ways or investigating population?
Random sampling through quadrats
Or
Systematic sampling along transects
What are three things to think about when using a quadrat?
Size: larger species=larger quadrat
Amount of results recorded:larger amount of species=more results recorded
Position:random
Why use random sampling?
Reduces sampling bias=more valid results!
What are the two different ways you can measure abundance?
1) frequency
2) percentage coverage
Describe mark release recapture?
Measuring abundance approximately
1) capture a sample
2) wait some time
3) return ad recapture a sample
4) use the mark release recapture equation to work out an estimation of population size
What is that mark release recapture equation and what does it show us?
Number of individuals in sample 1 x number of individuals in sample 2 \ number of mark individuals captured in sample 2.
It shows us an estimated population size.
What is needed so that mark release recapture is valid?
1) if possible no migration or immigration
2) few deaths and births
3) no harm to the animal and for the mark to not make them more noticeable to predators
4) for the mark to be strong so it will not get lost or rubbed off
Describe a typical population growth curve?
1) slow growth-small amount of people but thy are reproducing
2) rapid growth-more people to reproduce
3) slow decline until a stable point-could be because of food supply can’t cope with the demand of the population or increase predation.
Describe some abiotic factors effecting population size?
1) temperature-optimum temp for enzymes, further the temp is from the optimum the smaller the population size
2) light-more light, more photosynthesis meaning faster growing populations
3) ph-same as temp
4) water and humidity-more adapted species and higher transpiration rates in plants
Describe the two different types of competition?
1) instraspecific: animals from the same species competing for the same resources, the greater availability equals the larger the population
2) interspecific: animals from different species in the same niche competing until one of them is eliminated this is known as the competitive exclusion principle
Name two recent things that have caused the rate of human population to increase?
1) the development of agriculture
2) the development of manufacturing and the industrial revolution
Factors affecting population growth and the equations?
Immigration and migration
1) population growth= (immigration+births) - (deaths+migration)
2) percentage population growth=population change during the time/population at the start X 100
Factors affecting birth rate and equation?
1) economy
2) society
3) contraception
4) government
5) religion
Birth rate= amount of births per year/total population in that year X 1000
Factors affecting death rate and the equation?
1) age
2) life expectancy
3) food
4) sanitation
5) medical care
6) natural disasters
7) war
Death rate= number of deaths/total population X 1000
Define demographic transition?
Developed countries
High birth and death rate to a low birth and death rate
How to work out life expectancy?
When 50% of people are alive
