Chapter 11 Flashcards
(52 cards)
Theory of evolution
States that living things present on earth today are the diverse descendants of a single common ancestor
Natural selection
Advantageous traits are inherited that allow some individuals to adapt better to an environment making them survive and reproduce better than others
When would natural selection take place?
More offspring are produced than environment can support
Competition for limited resources/ mates
Why is genetic variation so important for natural selection?
Genetic variation allows some offspring to survive and reproduce better than others
Adapt better
What is responsible for selecting the most successful individuals in a population: the environment or the organisms themselves?
The environment
Micro evolution
Ex?
Changes that occur in the characteristics of a population (within one species)
Occurs quickly, results in changes of allele frequencies
Ex: skin pigmentation
Macro evolution
Ex?
The changes that give rise to new species
Over long periods of time
Product of many micro evolutionary events
Ex:elephant family tree (phylogeny)
Following the introduction of a new pesticide, a population of tomato hornworms evolves resistance to the pesticide over the course of 50 generations?
Micro or macro ?
Micro evolution
Birds and crocodiles share a common ancestor with dinosaurs.
Micro or macro?
Macro evolution
Adaptation
An inherited trait that increases the likelihood of survival and reproduction in a particular environment
Mutation
A heritable change in the DNA sequence of a gene
Change in amino acid can result in a new protein or messed up protein
Ultimate source of variation
Gene flow
The movement of individuals into or out of a population
Immigration: adds alleles; increases variation
Emigration: removes alleles; decreases variation
Genetic drift
Random change in allele frequencies in SMALL populations due to chance that may result in the loss of genetic variation an
Which results in the evolution of new species from a common ancestor?
Adaptive radiation
Macro evolution
Which is considered reliable evidence of evolution?
Fossils
Homologous chromosomes
Geographic distribution
DNA similarity
Artificial selection
Observation/testing
The wing of a bird and the wind of an insect are considered ____ structures?
Analogous
Can mutations result in micro evolution?
Yes, change in amino acids produce new proteins in the same species
Population Bottleneck
A dramatic reduction in population size that leads to a change in allele frequencies and possibly the loss of alleles (loss of variation)
Ex: Famine, hunting, plague, catastrophic events
Founder effect
A small group establishes a “founder population “ that is isolated from the original population
Chance matings can result in changes in allele frequencies
Ex: Amish with 6 fingers
Fossils
Preserved remains of once living organisms
Ex: imprint, amber, or bone fossils
Anatomical similarity (homologous structures)
Structures that look similar in appearance (anatomy) and function because they are inherited from a common ancestor
Ex: ears; feathers; forelimbs; bone arrangement in skeleton
Geographic distribution
Species that live in neighboring regions are more likely to share a common ancestor
Ex: euphoria plants found in S. America, S. Africa Australia
Molecular Homologies (DNA similarities )
If DNA sequence are very similar this is almost likely because they are inherited from a common ancestor
Speciation
The evolution of a new species or multiple new species from an ancestral species
