Survivorship Curves way of measuring rates of evolution plots number of genera surviving for different times (most still surviving after short time but as time passes members of original sample drop out one by one) slope of a survivorship curve measures rate of evolution of the group where group evolves fast, survivorship curve falls rapidly as species unlikely to survive for long curve is more drawn out for a slowly changing group.

K-Strategists Late reproduction Long life span Low mortality rate Extensive parental care Greater investment in maintenance and survival of adults At or near carrying capacity Examples: Sharks Elephants

R- strategists Early reproduction Short life span High mortality rate Little or no parental care Large investment in producing large numbers of offspring Below/above carrying capacity Largely regulated by density-independent factors (esp weather) Examples: Bony fish Grasshoppers Rats

Critical Number Minimum number of individuals of a species needed to maintain a healthy viable population. If a population drops below the critical number, the species will most likely go extinct.