BIO-110 Chapter 7

Charles Darwin published “On the origin of species by means of natural selection” on the date:

November 24, 1859

Ancient Greeks believed that species were _______ and ______

permanent, unchanging

The Middle Ages followed literal interpretations of the bible and believed that earth was relatively ___ (5000 years old) and that all _____ remains as it was orginally created.

new, life

Fossils were discovered in the _____ and scientist began to suspect that modern creatures came from ancient forms of extinct species.

1700s

Lamarck

was one of the first to suggest that life evolves through physical changes (giraffe stretching its neck overtime) that enable organisms to pass these adaptations to their offspring

Lyell

suggested that earth was very old and gradually changing through slow, accumulating processes such as erosion and earthquakes

Who was Wallace?

darwins colleague that was preparing to publish his own ideas of natural selection around the same time

evolution

all living species have descended from a succession of ancestral species, each of which accumulated modifications that helped them survive in their habitat

Natural selection

the process by which organisms with certain traits are more likely to survive and reproduce than other organisms

Penicillin which was once the most widely used antibiotic is now nearly useless due to the ______ of ________ bacteria

evolution, penicillin-resistant

Evolution does not result in steady progress through each generation. Natural selection cannot anticipate what an organism will need in the future. _____ is always driven by the local __________ _______ at that time.

evolution, environmental conditions

Only traits that are encoded within _____ can passed on to the next generation can possibly affect the _____ ____ of that generation

genes, reproductive success

artificial selection

the selective breeding of domesticated crops and animals (corn and dogs)

antibiotics

natural/synthetic drugs that inhibit or kill bacteria

Over time, antibiotics become useless because _____ have ______ resistance to them.

bacteria, evolved

Adaptation

an inherited character that enhances an organisms ability to survive and reproduce in a particular environment.

Fitness

relative survival and reproduction of one variant

Individuals with _______ for a particular _________ are more likey to survive and reproduce

adaptation, environment

Fossil record

ordered sequence of fossils found in layers of rock, with older fossils buried further down, and newer fossils near the surface

Radiometric dating

based on the breakdown of all radioactive isotopes (carbon-14) found in all living matter. (the lower the amount, the older it is)

Sedimentary fossils form when _____ from surrounding sediment replaces the organic matter of a dead organism. Amber is fossilized _____ ____, which preserves species in great detail. Organisms can be frozen in ___.

minerals, tree sap, ice

The fossil record provides evidence of evolution by…

ancient species such as a basilosaurus whale had hind back legs which shows proof of their land-walking evolutionary past

Biogeography

study of the distribution of species and ecosystems across different regions and how it changes over time

An example of biogeography is the dominance of _______ mammals in Australia vs the dominance of ______ mammals elsewhere. This is because 50 million years ago Australia split off from the other continents and became isolated.

marsupial, placental

Marsupials

complete embryonic development in a pouch

Comparative anatomy

the study of the similarities and differences in the anatomical structures of various species

Comparing the structure of human skeletons to bats and porpoises show that…. which is an example of comparative anatomy

the similarities among these limbs reflect their shared evolution from a common ancestor

Bioinformatics

by comparing the sequences of DNA and proteins from different organisms, scientists can gain insight into their shared evolutionary history. If the sequences of genes/proteins are closely matched, they have a recent common ancestor

A popular misconception about evolution is that…..

an individual can evolve

Evolution is defined only in terms of changes in a _______ over time.

population

What is a population?

a group of individuals of the same species living in the same place at the same time

Microevolution

a change in a population’s gene pool over a succession of generations; (short period of time)

In the example of microevolution in rabbits, how did the red version of the gene first arise in the population?

mutation

Gene pool

all the genes present in a population at a certain time.

Evolution acts on populations _______— members of the same species

interbreeding

Mutations

random changes to DNA, can be good bad or neutral

Sexual recombination in evolution

produces new arrangements of existing genes through crossing over and independent assortment

Darwinian fitness

reproductive success: the number of healthy offspring produced

What is an example of Darwinian fitness?

camouflaged gecko

Genetic drift

a change in a gene pool due to chance.

In a ______ population, the death or migration of a few individuals will have a ____ impact. But if the population is ______ or isolated, random changes can have a significant impact on the gene pool.

large, minimal, small

Bottleneck effect

a change in the gene pool because of a reduction in population size due to a disaster etc

If a disaster/change creates a small population it is called the…

founder effect

Gene flow

tends to make separate populations more genetically similar as they exchange genes.

As humans have begun to meet, mate, and exchange genes, the human population has become more ______ _____

genetically uniform

Sexual selection

a form of natural selection whereby certain individuals are more likely to attract mates and, therefore, have more offspring (peacocks)

Tectonic plates

huge irregularly shaped masses of the earth’s crust

4.6-541 million years ago. Earth was formed, oldest known prokaryotic fossils were found, oldest known eukaryotic fossils were found.

precambrian era

541-252 million years ago. Explosion in animal diversity, plant life dominates, animals migrate to land, mass extinction event wiped out 90% of all life on earth

paleozoic era

252-66 million years ago. First dinosaurs, early mammal (megazostrodon) and flowering plants began to dominate the land.

mesozoic era

66 million years ago to today. Dinosaurs went extinct, 200,000 years ago human creatures appeared.

cenezoic era

What event marks the start of the era in which humans evolved?

extinction of the dinosaurs

Macroevolution

encompasses such major changes as the origin of new species, mass extinctions, and the diversification of new forms of life.

Speciation

the formation of new and distinct species in the course of evolution.

Throughout Earth’s history, ancestral species gave rise to one or more new species, which in turn evolved again and again, giving rise to the incredible diversity we see today. This is called?

speciation

______ _____ refers to new structures or properties of organisms that allow them to perform new functions, often leading to evolutionary advantages. (based on macroevolution)

novel features

_____ _____ promote macroevolution. The evolutionary history of life on earth has been punctuated by brief catastrophic periods which in turn creates diversification after these wipe outs.

mass extinctions

Species

a population that is capable of interbreeding to produce healthy offspring that can themselves reproduce.

Reproductive barriers

prevent members of different species from interbreeding.

Members of a species often identify each other through specific rituals, markings, or smells. A peahen, for example, will only mate with a peacock who displays his large and colorful feathers.

This is an example of…..

behavioral isolation

Many species are able to reproduce only at specific times. Any attempts by members of another species to mate outside of this time frame will not be successful. For example, different species of toad will only breed at different times of year (early summer versus late summer, for example).

This is an example of….

mating time differences

If species live in slightly different habitats, they may never meet. For example, there are three different species of bristlecone pine trees. Each one grows only in areas that are well separated from the other species by mountains.

This is an example of….

Habitat isolation

Members of different species often cannot mate because their anatomies are incompatible. For example, in orchids, the pollen-bearing organs of many species have a specific structure that allows only one specific pollinator species to land and collect pollen.

This is an example of….

mechanical incompatibility

The gametes (sperm and egg) of different species usually cannot fertilize each other. This is particularly important during spawning season in aquatic habitats, when individuals of many different species release gametes into the same body of water. Multiple species of sea urchins, for example, may live alongside each other, but the sperm of one species cannot fertilize the eggs of another.

This is an example of….

gametic incompatibility

If two members of different species do manage to mate, a hybrid organism may result. Such hybrids may be unfit, or they may be sterile and unable to reproduce themselves, or they may produce unfit offspring. For example, a mule, a hybrid produced from a female horse and a male donkey, is always sterile.

This is an example of….

hybrid weakness

Speciation occurs when one ancestral species evolves into one or more new species. A key event in this process is often the ______ of a single population into two or more populations that are _____ from each other.

separation, isolated

Describes a pattern of evolution where species change slowly and gradually over long periods. This involves small adaptations accumulating over millions of years, transforming an ancestral species into a modern one.

graduated model

Punctuated equilibrium

Ex: mammals were relatively unchanged for millions of years until dinosaurs went extinct, and then a rapid series of speciation followed.

describes such periods of stasis (no change) interrupted by occasional bursts of speciation.

A physical barrier—such as the formation of a valley, mountain range, or body of water—arises that physically isolates populations from each other.

allopatric speciation

The emergence of a new species right in the midst of its parent population without geographic isolation.

Ex: two ancestral species of wheat produced a sterile hybrid. An error in cell division caused this hybrid to double its chromosomes. Self-fertilization then produced today’s species of modern bread wheat.

sympatric speciation

Taxonomy

identification, naming, and classification of species

All life is classified into one of three large groups called _____

domains

Domain-kingdom-phylum-class-order-family-genus-species. What is this called?

taxonomic hierarchy

Three-domain system

two domains of prokaryotes - bacteria and archea

one domain of eukaryotes - eukarya

Eukarya - divided into 3 kingdoms: plantae, fungi, animalia

The remaining eukaryotes that do not fit into the three kingdoms (plantae, fungi, animalia) are called ____

protists

A binomial (two-part) latin name, is made of a ____ that always begins with a capital letter and a _____ which is always in lowercase

genus, species

Systematics

is the classification of organisms to shed light on their evolutionary relationships.

A hypothesis about the evolutionary history of related species. The relative placement of different species on _____ _____ is based on several lines of evidence, such as their appearance in the _____ ____, and (when available) an analysis of their DNA and proteins.

phylogenetic trees, fossil records

An ancestral species and all its descendants—a distinctive branch in the tree of life. what is this called

clade

The study of evolutionary history; specifically, an approach to systematics in which organisms are grouped by common ancestry

cladistics

A branching diagram that represents a hypothesis about evolutionary relationships between organisms.

phylogenetic tree