Adaptation Flashcards
1
Q
Evolution Definition
A
- Evolution: Changes in the heritable properties of populations of organisms over the course of generations
- result in a a change in the frequency of alleles with in a gene pool over generations (doesn’t have to be an adaptation)
2
Q
Evidence for evolution (5)
A
- Fossils: shows transitional forms and new (but similar species that arise)
- Genetic variation w/in existing species
- Relationships between existing species (morphology, beh., genes)
- Imperfections (e.g. whales having small bones for hind legs)
- Can experiment and observe natural selection
3
Q
Common features of Darwin’s Natural Selection (3)
A
- Variation in traits (is what selection can act upon)
- Heredity
- Differential reproduction (trait survives better in those that can reproduce better)
- aka Darwinian fitness
4
Q
Types of traits and advantage they give
A
- Unfavourable traits: compromise reproduction (are therefore eliminated)
- Beneficial traits: are spread
- Neutral traits: can reside within population as neither help nor harm an organism
5
Q
Principles of natural selection (4)
A
- More offspring produced than what can survive
- Variation in particular trait
- Genetic basis of trait means it is inherited
- Differential reproductive fitness (beneficial trait = more offspring produced)
6
Q
Definition;
Biological species
Genotype
Phenotype
A
- Biological species: Groups of interbreeding natural populations that are reproductively isolated from other such groups
- explain why members of species resemble each other (form phenetic clusters) - Genotype: The set of genes carried by an organism
- Phenotype: The actual expression of the genotype (only a subset of genes are actually expressed)
7
Q
2 Modes of Speciation
A
- Allopatric Speciation: “Other country”
- Geographical separation of the diverging populations - is some barrier b/w populations
- Sympatric Speciation: “Same country”
- Without geographic speciation
8
Q
Mechanisms of Speciation (how does it occur)
- Pre-mating isolation (3 types)
- Post-mating isolation (2 types)
A
- Pre-mating isolation: Prevents cross breeding before occurs
- Seasonal/habitat isolation: Mates do not meet
- Behavioral isolation: Meet but do not mate
- Mechanical isolation: Attempt to mate but cannot
- Post-mating isolation: Prevents fertilisation or further development
- Hybrid mortality: egg fertilised but hybrid dies
- Hybrid viable but partially or completely sterile (e.g. mules)
9
Q
Defintion;-
Adaptation
Adaptive traits
A
- Adaptation: The process, through evolution, that allows organisms (or sets of genes) to better survive in their environment
- Adaptive traits are any physiological or behavioural feature that allows or enhances survival and reproduction
- Can have evolution without adaptations (but adaptation very strong driver for evolution
10
Q
Definition;
- Adaptive Radiation
- Adaptive Niche and e.g.
A
- Adaptive Radiation: a process of adaptive evolution in which variations of a single species fill different niches and eventually become a new species
- Adaptive Niche: The role of an organism in its community; what and where it eats, and what eats it
- is a finite number and hard to occupy new niche
- e.g. horses; as niches became available, began to fill them = 25 general of horses
- is a finite number and hard to occupy new niche
11
Q
Divergent Evolution in the Galapagos island
A
- Repeated colonisation from S america by plants and animals
- Founder effect: small no. of organisms go onto island and then speciate
- many population crashes = reshuffling of gene proportions
- Different islands also had organisms with different morphologies due to differences in environment
- is less competition if animals exploit a range of environmental niches
12
Q
Divergent Finches - Example of Divergent Evolution
A
- Land on the backs of other birds, open a wound and drink blood
- Probably arose from feeing on external parasites such as ticks
- also roll eggs from nests to break them and feed on contents
13
Q
Hybridization
- what it is and when likely to occur
- e.g. in wild
A
- Where similar animals come back together and mate, can lead to new species forming
- esp occur after unusal or catastrophic conditions
- many wild geese and ducks hybridise
- esp occur after unusal or catastrophic conditions
14
Q
Parallel evolution
Convergent Evolution
Divergent Evolution
A
Parallel Evolution: Occurs when species with a similar ancestor develop similar traits over time - due to shared environment or pressures
Convergent Evolution: Species that are not related, independently develop similar traits
Divergent Evolution: Where a species evolves into two or more different forms (have a common ancestor)
15
Q
Artificial Selection
A
- Where humans cause evolution by selecting for some traits
e. g. Trophy hunters for Alberta rams means horn size fell
