Introduction to Evolutionary Biology

Macroevolution

change among species over a long time span with

some species dying out and new species emerging

paleontology

study of fossils

Eohippus or Hyracotherium

earliest ancestor of the horse

Five toes, size of present day dog

Traits of Eohippus or Hyracotherium

Mesohippus and Miohippus

Ancestors of horses during the Oligocene period

Merychippus

Miocene horse with 3 toes in fore and three in hind leg, with median toe bearing entire body weight

Pliohippus

Pliocene horse

Equus

Pleistocene horse

Anatomy

Study of internal structure

Morphology

Study of external form and structure of various structure

Passiflora

Type of pea with stem tendril

Gloriosa

pea with the tip of its leaf modified as a tendril

Vermiform appendix

in humans, a remnant of the caecum that helps in digesting cellulose

Nictitating membrane or plica semilunaris

Completely unstretchable membrane in inner angle of human eye

Vestiges of the bone of the hind limb and pelvic girdle

Vestigial organ in the flesh of snake abdomen

Morula

The zygote divides to form a solid ball of cells called the ___.

Blastula

The morula transforms into a hollow ball called the ___.

Gastrula

The blastula transforms into two or three-layered ___ which organizes to form germ layers

Notochord and paired pharyngeal pouches

All vertebrates have these pouches during development.

1st pair: cavity of middle ear and auditory tube

2nd pair: tonsils

3rd pair: thymus and parathyroid glands

In humans, what do the notochord and paired pharyngeal pouches develop into?

Ernst Haeckel

Man who developed ‘recapitulation theory’ or ‘biogenetic law’

Ontogeny

Development of the organism starting from the ovum

Phylogeny

Evolutionary history of the individual

Colonial protozoan

In recapitulation theory, what does the blastula resemble?

Coelenterate

In recapitulation theory, what does the gastrula resemble?

Flatworm

In recapitulation theory, what does the three-layered embryo resemble?

biogeography

study of geographical distribution of plants and animals

Discontinuous distribution

animals showing ___ are descendants of the extinct population

1. Antarctic

2. Nearctic

3. Neotropical

4. Afrotropical

5. Palearctic

6. Indomalayan

7. Australasian

8. Oceanian

Eight biogeographical realms

Adaptive radiation

evolutionary process where new species are formed and adapts to new habitats and ways of life

gradual speciation model or gradualism

evolutionary model where species gradually over time in small steps

Punctuated equilibrium

Evolutionary model wherein a new species changes quickly from the parent species and then remains largely unchanged for long periods of time afterward

Gene

Section of a chromosome that encodes the information to build a protein

Allele

Varieties of the information at a particular locus

2

How many alleles can an organism have?

Homozygous

Two copies of the same allele at one locus

Heterozygous

Two different allele at one locus

Gene pool

The collection of available alleles in a population

Genotype

Genetic information contained at a locus; which alleles are actually present at a locus

Phenotype

Appearance of an organism; Results from the underlying genotype

Microevolution

change in the frequency of gene variants, alleles, in a population, typically occurring over a relatively short time period

Mutation

Source of genetic variation

Genetic drift

random change in allele frequencies that occurs in a small population

Gene flow

when individuals move into or out of a population

Natural Selection

when there are differences in fitness among members of a population

Gametes

mutations that matter for evolution are those that occur in ___

Bottleneck Effect

When a population suddenly gets much smaller

Founder Effect

When a few individuals start or found a new population

Fewer

The stronger the selective pressure or the selection event, the ___ individuals make it through the sieve of natural selection.

Hardy-Weinberg Equilibrium

Principle that states that a population’s allele and genotype frequencies will remain constant in the absence of evolutionary mechanisms

1. no mutations

2. no immigration/emigration

3. no natural selection

4. no sexual selection

5. a large population

The Hardy-Weinberg principle models a population without evolution under the following conditions: