Topic 7A: Descent with Modification

what is the most general taxon

domain

what is the most specific taxon

species

every living thing falls under 1 of which 3 domains

eukarya, bacteria (prokaryote), archae (prokaryote)

which two taxon are used as the scientific name for all organisms?

genus + species

who is Carolus Linnaeus

grouped similar species into increasingly general categories

• developed taxonomy

• binomial nomenclature

what is taxonomy

a branch of biology dedicated to the naming and classification on all forms of life

what is binomial nomenclature

a two-part naming system that includes the organism’s genus and species

who was Charles Lyell

• developed the idea that the geologic processes that have shaped the planet have been uniform over a long period of time

• important conclusion: the earth must be very old

what is each layer of rock called

a strata

• deeper stratas are older

what was Jean-Baptiste de Lamarck use and disuse theory

more used parts of the body become larger and stronger, while less used parts deteriorate

what was Jean-Baptiste de Lamarck’s inheritance of acquired characteristics theory

characteristics acquired during an organism’s lifetime could be inherited

what’s a way to memorize use and disuse theory

“if you don’t use it, you lose it”

what is Charles Darwin’s natural selection theory

explains how adaptations arise

• adaptation: heritable characteristics that enhance organisms’ ability to survive and reproduce in specific environments

what does natural selection involve

1. individuals in a population vary in their traits, most being heritable

2. a population can produce far more offspring that can survive

3. individuals with inherited traits that are better suited to the local environment are more likely to survive and reproduce than individuals less suited

4. evolution occurs as the unequal reproductive success of individuals ultimately leading to adaptations of their environment

what is variation

there is genetic variation within a population which can be inherited

what is competition

overproduction of offspring leads to competition for survival

what are adaptations

individuals with beneficial adaptations are more likely to survive

what is selection

over many generations, there is a change in allele frequency (evolution)

Natural selection can lead to _____ and _____ _____

speciation; adaptive radiation

what is speciation

creation of a new species

what is adaptive radiation

the relatively fast evolution of many species from a single common ancestor

what is artificial selection

the process by which species are modified by humans

• ex. Breeding dogs

Individuals do not evolve. ____ evolve.

Populations

What Are Some Direct Observations of Evolutionary Change

Insect populations can rapidly become resistant to pesticides such as DDT

Evolution of drug-resistant viruses and antibiotic - resistant bacteria

What is homology

characteristics in related species can have an underlying similarity even though they have very different functions

What are homologous structures

anatomical signs of evolution

• same structure, different function

What are analogous structures

body parts

• different structure, same function

• goal is to adapt to the same environment

What are embryonic homologies

many anatomical homologies in embryos are not visible in adult organisms

ex. All vertebrate embryos have a post-anal tail and pharyngeal pouches

what are vestigial organs

structures with minimal, if not any importance to the organism

what are molecular homologies

shared characteristics on the molecular level

• ex. Amino acid sequences coding for hemoglobin in primate species show great similarity, indicating a common ancestor.

what is molecular biology

• molecular similarities (similar DNA/proteins) provide evidence for the shared ancestry (common ancestor)

• comparisons of DNA sequences can show how closely related or different two species are

what does convergent evolution explain

why distantly related species can resemble one another

• this takes place when two organisms develop similarities as they adapt to similar environmental change

• ex. torpedo shapes of penguin, dolphins and sharks are all solutions to movement to an aqueous environment

what is divergent evolution

two or more related species evolve into increasingly dissimilar forms

what is biogeography

the geographic distribution of species

• species in a discrete geographic area tend to be more closely related to each other