darwin- pack 18 Flashcards
if animals are unable to move to new habitats what are their two possible outcomes
adapt to the new conditions of face local extinction
what does climate change provide
a selection pressure for natural selection and evolution
what was the first thing that darwin observed
organisms produced more offspring than can survive and reproduce- numbers in natural selection stay much the same over time
what did darwin conclude after his first observation
there’s struggle for existence as there’s competition between members of the same species for survival as population increases in size, environmental factors half the increase as many individuals die due to predation, competition for food and other recourses, rapid spread of disease resulting from over overcrowding
what are the axis label on this
x = time
y = n.o individuals in the population
describe 1
population grows slowly due to low numbers of reproductive individuals who may widely disperse
describe 2
population grows exponentially doubling at regular intervals, few factors limiting growth little competition for food and space, predation and disease are low
describe 3
population growth slowly as factors limit growth, death rate and or birth rate decreases
describe 4
birth rate and death rate balance, population has reached carrying capacity of the environment so this is the maximum population size the habitat can support
what was the second thing that darwin observed
there is a huge variation within species
what did darwin conclude after his second observation
individuals that are best adapted to conditions in their environment are more likely to survive and breed as they have a selective advantage - will be more individuals with these adaptive features in the next generation but organisms that aren’t more likely to die before maturity so don’t produce many offspring
