Bio

(b) Each of the following relates to an aspect of evolution by natural selection. Explain three of the following: (i) Convergent evolution and the similarities among species (ecological equivalents) in a particular biome (e.g., tundra, taiga, etc.) (ii) Natural selection and the formation of insecticide-resistant insects or antibiotic-resistant bacteria (iii) Speciation and isolation

(i)Different species exhibit adaptations as a result of the same environment (ii)An inherited characteristic enables the organism to resist the effect of the toxin (iii)A single population divides into two reproductively isolated populations or equivalent (use of gene pools)

How does natural selection work?

random mutations give rise to slightly differing traits. Animals with favorable traits survive to reproduce more often and reproduce more. This means that over time that new phenotype becomes more common. Adaptation occurs most rapidly in times of stress in which the majority of a population dies and only the animals who preform the best in the new conditions survive.

How do genetic drift and founder effect work? Bottleneck?

· Genetic Drift: change in Frequency of heritable trait due to random events. o Founder effect: small population colonize a new territory o Bottleneck: population is reduced to very small numbers o Random change in frequency

What are different mechanisms of natural selection? Sexual? Kin?

· Natural selection: Survival of the fittest · Sexual Selection: traits to attract mates. Ex. Peacocks · Kin Selection: one individual sacrifices fitness so that relatives gain fitness.

How can the Hardy-Weinberg principle of genetic equilibrium be used to determine whether this population is evolving?

Allelic frequency changes or five conditions that do not change if population is not evolving Means of measurement/detection

What are different definitions of species? When do they apply?

Biological definition of Species: If parents produce a fertile offspring than they are the same species. Definition doesn't work for bacteria. Morphological definition of species: cant use biological definition for fossils. · Introgression: When two species that have recently separated they may be able to interbreed and create a new species. Phylogenetic definition of Species: shares a common ancestry.

(c) Identify a particular environmental change and describe how it might alter allelic frequencies in this population.

Explain which condition of the Hardy-Weinberg principle would not be met. (4 points maximum) Environmental change identified (1 point) (first one scored) Explanation of how allelic frequency changed (1-2 points) Which Hardy-Weinberg condition not met (1 point)

What is fitness? adaptation?

Fitness is an organisms ability to survive and thrive in the existing conditions. The fittest animals have a higher chance o surviving to reproduce.

Evolution is one of the unifying themes of biology. Evolution involves change in the frequencies of alleles in a population. For a particular genetic locus in a population, the frequency of the recessive allele (a) is 0.4 and the frequency of the dominant allele (A) is 0.6. (a) What is the frequency of each genotype (AA, Aa, aa) in this population? What is the frequency of the dominant phenotype?

Frequency AA = .36 Frequency Aa = .48 Frequency aa = .16 Frequency dominant phenotype = .84

How do gene flow and gene pool relate?

Gene pool~ the sum of alleles of any given gene in a breeding population.

What is the evidence of evolution?

Homologous structures

Post-zygotic barrier? Examples?

Post Zygotic barriers: barriers that prevent the zygote from becoming fertile adults. · Hybrid inviability: when the gametes of the two different species unite the zygote they form cannot survive to maturity · Hybrid sterility: the offspring of parents of two species are infertile. · Hybrid breakdown: first generation is viable and fertile, but later generation have developmental and reproductive problems.

What is a pre-zygotic barrier? What are different examples?

Pre-zygotic Barriers: barrier that prevents the formation of a zygote. · Geographic Isolation: gene flow between populations is blocked by geographic features. o Islands isolate things that cant fly o Galapagos · Behavioral · Temporal · Mechanical · Gametic:

(a) Explain the theory of evolution by natural selection as presented by Darwin.

Reproductive potential: the ability to over produce Variability: inheritable changes or mutations linked to variability Limited resources: biotic or abiotic Competition: intraspecific struggle for existence Differential Reproduction: reproductive success of variants Generations: time needed for evolution to occur

What is a ring species?

Ring Species: a set of populations that can interbreed except between those with most distant common ancestry.

Compare gradual evolution to punctuated equilibrium?

Tempo of evolution: · Gradualist model: evolution occurs at a constant, gradual rate · Punctuated equilibrium · Most populations experience little change during their history, but this equilibrium is punctuated by short events of rapid change and speciation. What are the general patterns of natural selection?

What is the heterozygote advantage?

The heterozygote advantage is when a heterozygote is more fit than either the pure breeding dominant and recessive.

What did Darwin and Wallace contribute to the theory of biological evolution?

What did Darwin and Wallace contribute to the theory of biological evolution?