CHAPTER 3.2 Natural Selection and Modern Synthesis Flashcards
- there is genetic variation within a population which can be —
- overproduction of offspring leads to — for survival
- individuals with beneficial adaptations are more likely to survive to pass on their genes
- over many generations, there is a change in —
inherited
competition
allele frequency
Variation
- organisms inherit characteristics from both of their parents and each organisms get a different combination of features - —
- changes in characteristics of organisms as affected by their surroundings - —
inherited variation
environmental variation
Fraternal twins
-develop from — of egg and sperm
-same-sex or one of each
- —- placentas
identical twins
-develop from — egg and sperm
-same sex
- — placenta
two sets
separate
same
shared/separate
-product of overpopulation
-species tend to produce more offspring than the environment can support, hence, there is struggle for survival
-interaction between species over a limiting resource that negatively affects their population growth rates
competition
Competition
-within one/same population, there could be fluctuations on the number of offspring
-two or more population that are competing with each other causing decrease/increase of population
intrapopulation oscillation
interpopulation oscillation
-evolutionary effects of competition
-because of limited resource, the populations with the same need will compete, leading to exhaustion, separates unto different habitat. exposing to different resources - mutation
character displacement
Types of Competition
Base of Taxonomical Relationship
1. same species that compete for limited resources (carrying capacity)
2. asymmetric competition, two different species (abilities) between two individuals of different species competing for the same resources
-reduction in the population of the weaker species, stronger ones survives and reproduces
-regulates ecological communities
intraspecific competition
interspecific competition
types of competition
Base on Influence
1. an interaction where the species living in an ecosystem directly influence each other by affecting the availability of resources in the ecosystem
2. species influence the availability of resources indirectly, species involved usually exist in different ecological niche
direct competition
indirect competition
types of competition
Base on Mechanism
3. both competing species are preyed upon by the same predator
1. directly influence the process of foraging, reproduction of others, or prevent the establishment of the species in an environment, ex. fight, steal, kill
2. species are connected by a common limiting resource that acts as an intermediate. ex. space, water
apparent competition
interference competition
exploitative competition
two closely related species tend to be more distinct when they are sympatric than when they are allopatric
In allopatric speciation, — or divergence has to take place, while in sympatric speciation, — that live in the same habitat
Allopatric speciation is the most common mechanism of forming new species, while sympatric speciation is driven by genetic or sexual isolation.
character displacement
geographical isolation
new species evolve from one ancestral species
-interspecific interference competition (direct competition)
-shifts in traits that affect the rate, intensity or outcome between sympatric species
-interspecific exploitative competition (indirect competition)
-shifts in traits that affect resource overlap between sympatric species
agonistic ACD
ecological ECD
-adjustment of organisms to their environment in order to improve their chances at survival
-result of genes the organism inherits from its parent
adaptation
— feature of an organisms’ body that helps it to survive/ reproduce ex. long neck, tough tongue
—responses made by an organism ex. 10g water intake at a time
—enzymes, chemical ex. heart thickness
structural adaptation
behavioral adaptation
physiological adaptation
physical resemblance of two/more species resulting from inherent advantages of similar appearance; learned/ innates
immitative species -
species it resembles -
mimicry
mimic
model
Three Fundamental Types of Mimicry
-several noxious species come to resemble each other
-benign species resembles noxious/ dangerous
-noxious/ dangerous species resembles a benign one
mullerian
batesian
agressive
- environmental pressures lead to differential reproduction within a population, hence, resulting in —- of traits
- it is a process where organisms are subjected to causing changes in —
- surviving traits would be prevalent in future population species
selection
allele frequency/ gene pool if they are able to survive and reproduce
- selection acts at the level of the individual and selects for individuals with greater contributions to the gene pool of the next generation
- the contribution an individual makes to the gene pool of the next generation relative to the contributions of other organisms/ individuals
evolutionary fitness
relative fitness
Types of Selection
- for moderate traits against both extremes
- for one extreme trait against the other extreme
- for both extremes against moderate traits
- fitness of phenotypes is dependent on its frequency relative to other phenotypes in a given population
a. common phenotypes in a population and decreases the genetic variance
b. selects for rare phenotypes in a population and increases genetic variance
stabilizing selection
directional selection
disruptive selection
frequency-dependent selection
positive frequency-dependent selection
negative frequency
selection pressure on males and females to obtain mates, can result in traits designed to maximize sexual success
often results in the development of secondary secual characteristics, which help to maximize a species’ reproductive success, but do not provide any survival benefits (handicap principle)
a. competition among members of same sex (usually males) for access to mates
b, members of one sex (usually females) choose members of the oppositve sex
sexual selection
intrasexual selection
intersexual selection
