Preliminary Term 2 Flashcards
What is a population?
All of the organisms from the same species living in an particular area
What is a community?
A group of populations in an particular area
What is an ecosystem?
A community of living organisms that interact with each other and their surrounding enviroment
Biotic factors?
The living components of an ecosystem eg, plants, animals, fungi, bacteria
Abiotic factors?
The non-living component of an ecosystem eg, light, temperature, wind, pH, salinity, water, shelter etc
Selection pressures?
When abiotic and biotic factors exert pressure on an organism and its survival ability, selection pressures can be advantageous or disadvantageous and affect an organism’s behaviour and reproduction.
How does population size change in the effects of selection pressures?
Gradually, the population changes and genes that improve survival and reproduction will become more common, while genes that are disadvantageous to survival and reproduction will become rare. This change in the genetic makeup of a population is called evolution, altering biodiversity e.g. predator and prey relationships.
What is an evolutionary change?
Evolutionary change is the heritable change in populations and species over time, due to mechanisms such as natural selection, random genetic drift, and sexual selection
What’s an adaptation?
The development of specific features of an organism that enable them to survive and reproduce in a a specific environment.
What is a structural adaptation?
Relating to the physical aspects of the organism.
What is a behavioural adaptation?
Relating to the action or behaviour of an organism.
What is an physiological adaptation?
Relating to the internal bodily functioning of an organism.
What is Darwin’s theory of natural selection?
It suggests that organism’s with traits most favourable to the environment tend to survive, produce more offspring and pass their favourable trait to their offspring. Selection pressures drive natural selection.
What is natural selection?
It suggests that organism’s with traits most favourable to the environment tend to survive, produce more offspring and pass their favourable trait to their offspring, the factors that determine favourability are abiotic factors, competition and predation. Selection pressures drive natural selection.
What is genetic variation?
It is the difference in DNA sequences between individuals within a population. It is important in the process of natural selection because individuals’ traits vary in suitability for selection pressure and it is called ‘speciation’ when natural selection produces a new species.
