Chapter 1: 1.1 Descent with Modification Flashcards
Define:
Heritable Variation
Variation within species and between species
Define:
Phenotype
Physical characteristics (shape, function, behavior)
Define:
Genotype
Specific combination of genes and alleles
In heritable variation:
What are the two requirements that must be met?
- Traits must be expressed
- Traits must be heritable
True or False:
Natural selection is random
False. VARIATION is random, but natural selection is NOT random
What does natural selection select?
It selects individuals that do the best in the environment
List:
Sources of Variation
- Mutation
- Meiosis
- Recombination
- Independent Assortment
- Fertilization
Define:
Mutation
Random errors in DNA replication
Define:
Meiosis
Sexual reproduction which can introduce genetic variation
Define:
Recombination
Chromosomes cross and exchange sections
Define:
Independent Assortment
Offspring receive one of each chromosome at random from the parent
Define:
Fertilization
Combining two parental genomes
Selection acts on…
The individual
Define:
Agent of selection
Environmental feature that consistently produces differential survival
* Causes the weaker/less adapted to die off
Give examples of:
Agents of selection
- Heat
- Drought
- Salinity
Define:
Selective pressure
How intensely the environment is selecting a trait
* E.x. What fraction of the population dies each year due to drought
What is biotic selective pressure?
Living pressure (E.x. prey, predators)
What is abiotic selective pressure?
Non-living pressure (E.x. rainfall, temperature, nutrients)
What does natural selection depend on?
Environment
True or False:
Natural selection moves towards perfection
False
Natural selection is ——————-
Context-dependent
List:
Requirements of Natural Selection
- Heritable Variation
- Limited Resources
- Differential Survivial
In natural selection, given properties the population will…
Adapt
List:
Evidence for Evolution (7)
- Fossils Records
- Comparative Embryology
- Biogeography
- Vestigial Structures
- Genomics
- Artificial Selection
- Resistance in Pests
Explain Evidence for Evolution:
Fossil Records
See species change gradually through time
Explain Evidence for Evolution:
Comparative Embryology
Distantly related species have similar embryonic stages (due to shared ancestry)
Explain Evidence for Evolution:
Biogeography
The distribution of related species matches evolutionary theory
Explain Evidence for Evolution:
Vestigial Structures
Some traits have no current function and are slowly disappearing (e.x. Whale pelvis, human tailbone)
Explain Evidence for Evolution:
Genomics
DNA is more similar between closely related species
Explain Evidence for Evolution:
Artificial Selection
We have selectively bred traits to produce desired phenotypes (e.x. corn, dogs)
Explain Evidence for Evolution:
Resistance in Pests
Pests have become resistant to our methods of control
