Populations Flashcards
What is a population?
All the organisms of one species in a habitat.
What is a habitat?
The place where an organism lives.
What is a community?
Populations of different species in a habitat.
What is an ecosystem?
All the organisms living in a particular area, and all the non-living (abiotic) conditions.
What is an adaptation?
A feature that members of a species have that increases their chance of survival and reproduction.
Why should a sample be random?
To avoid bias and to get a varied sample.
How do you calculate population growth?
Birth rate - death rate
What do survival rates and life expectancy show?
Survival rates show the % of people still alive in a population after a given amount of time.
The average life expectancy is the age at which 50% of the population is still alive.
How would you calculate population size using birth rate, death rate, and life expectancy?
(Birth rate - Death rate) X life expectancy
What does a statistical test that shows a significant difference of P = 0.05 mean?
There is a probability of 5% that difference in frequencies are due to chance.
How can you investigate percentage cover of a plant in a field?
You could use quadrats. Place several on the ground at random locations. Record the percentage of each quadrat that’s covered by the organism your looking for. Percentage cover can be estimated by averaging the data collected in all of the quadrats.
Describe the differences in population size and structure at stage 1 compared to stage 5 of the DTM.
At stage 1 the population size is low and not increasing. At stage 5 the population is high but shrinking. At stage 1 the population structure is made up of a lot of young people and very few older people. But at stage 5 there are very few young people and lots of older people.
Do small animals have a high or low surface area : volume ratio?
Higher
