2nd S emester Flashcards
(139 cards)
The number and the kinds of organisms living on Earth at a particular time is called?
biological diversity
The _ is the scientific explanation of the diversity of life.
evolutionary theory
_, or change over time, is the process of how present-day organisms have descended from ancient ones.
Evolution
A _ is a well-supported, testable explanation of a natural phenomenon.
theory
A key factor for an organism to thrive and reproduce depends on how well-suited the organism is to the environment.
Natural Selection
The ability of an individual to survive and reproduce in a specific environment is called its?
fitness
The concept of fitness is the central process of evolution by _.
natural selection
Species descend through generations with several changes over time. This principle also implies that organisms are related to one another.
Descent with modification
The principle of evolution that states that all organisms share common ancestry.
Common descent
3 types of natural selection that can affect populations:
Directional selection
Stabilizing selection
Disruptive selection
_ happens when a change in the environment causes a change in the observable spectrum of phenotypes.
In this process, organisms with a phenotype that is well-suited to their current environment are more likely to survive.
Directional selection
_ occurs when intermediate phenotypes are more likely to survive in the environment.
Stabilizing selection
_ occurs when extreme phenotypes are more likely to adapt to the environment.
Disruptive or diversifying selection
In _, nature provides the variation among different organisms so that humans can select the variations that are useful to them.
artificial selection
Artificial selection can be done through a technique called _. This type of mechanism is done by farmers and breeders.
In this process, individuals with desirable traits or characteristics are bred to increase the chances of having offspring with the same desirable traits.
selective breeding
_ also contributes to the population change from one generatin tho the net. This is described as the selected probability of mating with another individual in the population.
Nonrandom mating
_ is when individuals are more likely to mate with their close relatives thai mith distant relatives. In this manner, individuals choose their mates based on their genetic history.
Inbreeding
Inbreeding may lower the population’s ability to survive and reproduce, a condition called _.
inbreeding depression
_, or assortative mating, happens when individuals select distant relatives than close relatives as their partners. In this type of breeding, individuals with similar phenotypes are more likely to mate.
Outbreeding
_ is caused by unpredictable changes in allele frequencies due to small population sizes. Thus, a certain allele can be passed on to numerous offspring by chance.
Genetic drift
2 examples of random genetic drifts that can have significant effects in small populations:
Population bottleneck
Founder effect
_ occurs when a sudden sharp decline in the population (usually from natural disasters such as volcanic activities and strong weather disturbances) results in a drastic reduction of the total genetic diversity of the original population.
Population bottleneck
The _ happens when there is a loss of genetic variation because of the migration of a small subgroup in a population.
founder effect
_ is the change in the structure of a gene caused by alterations in the DNA sequence of an organism.
Mutation