Exam 1 Flashcards
evolution
change in the genetic composition of a population over time
adaptation
change in which a species becomes more suited for its environment
What are the 4 requirements for evolution by natural selection to occur?
- Variation
- Struggle
- Heritability
- Differential reproduction: reproductive success would be different based on the traits one has, how many will survive and reproduce depending on the traits one has
Who discovered the idea that species are related by shared ancestry (two people)?
Darwin and Wallace
Convergent evolution
Independent evolution of similar features in species of different periods in time.
Convergent -> no shared ancestry, evolved trait independently
Divergent evolution
species have a common ancestor, traits are homologous
Coriolis Effect
Rotation of earth fastest at equator, deflection of surface air to the west as it moves towards equator
At what latitudes are deserts most present? Why?
- 30 degrees Nouth and South
- Hadley cells bring hot and dry air around these latitudes.
Why are higher temperatures closest to the equator?
Direct sunlight hits the equator more intensely which causes an increase in temperatures
What causes seasons?
Earth’s tilt of axis
What has to be fulfilled for a growing season?
Precipitation is higher than temperature
Temperature must be higher than 0 degrees C
(most rainforests are found near equator)
Homology
features that are similar due to their shared ancestory
Extinction
Cuvier- establishes extinction
-is an ongoing process throughout history of life
Heritability
proportion of trait variation in a population is accounted for by genetic variation in the population
Artificial Selection
selection affected by humans
4 processes that lead to evolution
- natural selection -> leads to adaptation
- Mutation
- Migration
- genetic drift
what is b, B, d, D, r, N
b= per capita birth rate
d= per capita death rate
B= # of births
D= # of deaths
r= per capita birth rate
N= number of individuals
population momentum
is why the population will keep increasing
due to large number of females being born
what is the current world population size?
8 billion
what is the recent average doubling time?
50 years
What has led to a shorter time to add a billion people to the human population?
improvements of technology/ medicine
Agriculture advancements
Hygiene
High fecundity rates
Even though r is decreasing, why is N still increasing?
Because r is still greater than 0 so N will still be increasing
What are some known ways to reduce fertility rates?
Birth control, education
What is the value of r when N = K?
r=0
