Hippopotamuses are more closely related to cows that to javelinas.
Toothed whales are more closely related to mouse deer than to hippopotamuses.
Javelinas and pigs are more closely related than baleen whales and toothed whales.
Cows and mouse deer are more closely related that javelinas and pigs.
A new species of horse suddenly appeared
Horses slowly developed over time
Horses have similar stages of rapid embryological development
Horses have a common ancestry with other hooved animals
The morality rate of the guppies will increase.
Offspring will stop competing for resources.
There will be an increase in mutations in the offspring.
There will be an increase in the number of colorful guppies.
Male and female deer come into contact with each other only in the fall.
Large predators are not found in deer habitats during the spring and summer months
Giving birth only in the spring and summer insures that offspring are born when food is most available.
Deer give birth in the spring and summer in order to avoid being pregnant during the hot summer months.
The rabbits will mutate their genes and express genes that increase their speed.
Slower rabbits will develop stronger legs and pass this trait to their offspring.
Rabbits will mate and produce offspring with a different species that has faster runners.
Faster rabbits will survive and reproduce increasing the average speed of the rabbit.
Limited availability of water
Competing for mates
Large numbers of natural predators
Food sources that are hard to find
The chances of a mutation occurring in the cheetah population are decreased, increasing the cheetah survival rate.
The gene pool remains in equilibrium and future generations of cheetah offspring are stronger and better adapted to their environments.
The cheetah population becomes less likely to survive an outbreak of a disease or an environmental change, increasing the chance of species extinction.
Genetic variability is maintained from older cheetah populations that have survived and endured environmental stressors.