Download Organizing Information About Species

Organizing Information
About Species
Chapter 19 Part 1
Impacts, Issues
Bye Bye, Birdie
 Hawaiian honeycreepers evolved into many forms
to exploit varied habitats – recent changes have
driven many species to extinction
19.1 Taxonomy and Cladistics
 Taxonomy
• The science of naming and classifying species
 We group species based on what we know
about their evolutionary relationships
Linnaean Classification
 Carolus Linneaus ranked organisms into ever
more inclusive categories (taxa)
•
•
•
•
•
•
•
•
Species
Genus
Family
Order
Class
Phylum
Kingdom
Domain
Naming Species
 In the Linnaean system, each species is given a
unique, two-part scientific name
• Example: the dog rose, Rosa canina
 The first part is the genus name
 The second part is the species name
Linnaean Classification
DOMAIN
KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES
COMMON
NAME
Eukarya
Plantae
Magnoliophyta
Magnoliopsida
Apiales
Apiaceae
Daucus
carota
carrot
Eukarya
Plantae
Magnoliophyta
Magnoliopsida
Rosales
Cannabaceae
Cannabis
sativa
marijuana
Eukarya
Plantae
Magnoliophyta
Magnoliopsida
Rosales
Rosaceae
Malus
domesticus
apple
Eukarya
Plantae
Magnoliophyta
Magnoliopsida
Rosales
Rosaceae
Rosa
acicularis
arctic rose
Eukarya
Plantae
Magnoliophyta
Magnoliopsida
Rosales
Rosaceae
Rosa
canina
dog rose
Fig. 19-2, p. 302
Ranking Versus Grouping
 Rankings do not necessarily reflect evolutionary
relationships (phylogeny)
 Cladistics determines evolutionary relationships
by grouping species on the basis of shared,
quantifiable features (characters)
 A clade is a group of species that share a set of
characters
Evolutionary Tree Diagrams
 Evolutionary tree diagrams summarize the
evolutionary history of a set of organisms
• Show networks of evolutionary relationships
 Sister groups are two lineages that emerge from
a node on a cladogram at the same time
Cladograms
Fig. 19-3a, p. 303
hagfishes
lampreys
cartilaginous fishes
ray-finned fishes
lobe-finned fishes
lungfishes
amphibians
amniotes
(reptiles,
birds, and
mammals)
Fig. 19-3a, p. 303
Fig. 19-3b, p. 303
hagfishes
animals with a skull
lampreys
cartilaginous fishes
ray-finned fishes
lobe-finned fishes
lungfishes
amphibians
amniotes
(reptiles,
birds, and
mammals)
animals with a backbone
and a skull
animals with a swim
bladder or lungs, a
backbone, and a skull
animals with four limbs,*
a swim bladder or lungs,
a backbone, and a skull
animals with four
membranes around their
eggs, four limbs,* a swim
bladder or lungs, a
backbone, and a skull
* Snakes are included in
these clades because
their ancestors had four
legs.
Fig. 19-3b, p. 303
19.1 Key Concepts
Taxonomy
 Each species is given a two-part scientific name
 Traditional classification schemes rank species
into a hierarchy
 Newer methods that group species by shared
ancestry more appropriately reflect evolutionary
history than do traditional ranking systems
19.2 Comparing
Body Form and Function
 Comparisons of body form and structures yields
clues about evolutionary relationships
Morphological Divergence
 Morphological divergence
• A body part from a common ancestor becomes
modified differently in different lines of descent
 Homologous structures
• Similar body parts that reflect shared ancestry
• The same genes direct their development
Morphological Divergence
21
3
pterosaur
4
1
2
chicken
3
2
penguin
3
21
3
4
5
1
stem reptile
2
23
1
4 5
porpoise
bat
2
3
4
5
1
2
3
4
5
3 4
5
1
human
elephant
Fig. 19-4, p. 304
Morphological Convergence
 Morphological convergence
• Evolution of similar body parts in different lineages,
not in a common ancestor
 Analogous structures
• Body parts that evolved independently in separate
lineages in response to the same environmental
pressure
Morphological Convergence
Fig. 19-5a, p. 305
Fig. 19-5b, p. 305
Fig. 19-5c, p. 305
Fig. 19-5d, p. 305
Insects
Bats
Humans
Crocodiles
wings
Birds
wings
wings
limbs with
5 digits
Fig. 19-5d, p. 305
19.2 Key Concepts
Comparing Body Form
 Species may be grouped on the basis of
similarities or differences in body form
 Different lineages often have similar body parts,
which may be evidence of descent from a
shared ancestor
19.3 Comparing
Patterns of Development
 Similar patterns of embryonic development are
the result of master genes that have been
conserved over evolutionary time
 May be evidence of evolutionary relationships
Similar Genes in Plants
 Homeotic genes (master genes) guide formation
of specific body parts during development
 Mutation in one homeotic gene can disrupt details
of body form
• Example: Apetala1 results in mutated flowers
Developmental Comparisons in Animals
 Embryos of many vertebrate species develop in
similar ways
 Example: All vertebrates go through a stage with
four limb buds and a tail
• Dlx genes signal appendage formation
• Hox gene suppresses the Dlx gene
Comparative Embryology
Fig. 19-6a, p. 306
Fig. 19-6b, p. 306
Fig. 19-6c, p. 306
Fig. 19-6d, p. 306
Fig. 19-6e, p. 306
Master Genes and Appendages
Fig. 19-7a, p. 307
Fig. 19-7b, p. 307
Fig. 19-7c, p. 307
Fig. 19-7d, p. 307
Forever Young
 Some differences between closely related species
resulted from changes in rate of development
 Example: Chimpanzee and human skulls
• Early stages are similar
• Human skulls undergo less differential growth;
juvenile traits persist
Differential Growth Patterns
adult
proportions in infant
Fig. 19-8a, p. 307
proportions in infant
adult
Fig. 19-8b, p. 307
adult
proportions in infant
proportions in infant
adult
Stepped Art
Fig. 19-8a, p. 307
Animation: Mutation and proportional
changes
19.3 Key Concepts
Comparing Patterns of Development
 Species may be grouped on the basis of
similarities or differences in patterns of
development
 Lineages with common ancestry often develop in
similar ways
19.4 Comparing DNA and Proteins
 Kinds and numbers of biochemical similarities
among species reflect evolutionary relationships
 DNA and amino acid sequence differences are
greatest among lineages that diverged long ago,
and less among recently diverged lineages
Molecular Clocks
 The accumulation of neutral mutations in the DNA
of a lineage are like ticks of a molecular clock
that increase over time
 DNA sequences of closely related species are
more similar than those of distantly related ones
Molecular Comparisons: Amino Acids
 Comparisons of amino acid sequences in proteins
reveal relationships among species
 Most mutations are selected against, but some
are adaptive
 Essential genes, such as the one for cytochrome
b, are highly conserved across species
Comparing Cytochrome b Sequences
Molecular Comparisons: DNA
 Even if the amino acid sequence of a protein is
identical among lineages, the nucleotide
sequence of the gene that encodes it may differ
 Mitochondrial DNA is inherited intact from a single
parent, so differences between maternally related
individuals are due to mutations
DNA Sequence Comparison
Oreomystis mana (Hawaii creeper)
Paroreomyza montana (Maui alauahio)
Pseudonestor xanthophrys (Maui parrotbill)
Hemignathus munroi (akiapolaau)
Loxops coccineus (Hawaii akepa)
Palmeria dolei (akohekohe)
Vestiaria coccinea (iiwi)
Himatione sanguinea (apapane)
Oreomystis bairdi (akikiki)
Hemignathus virens (amakihi)
Fig. 19-10b, p. 309
19.4 Key Concepts
Comparing Biochemistry
 Species may be grouped on the basis of
similarities or differences in DNA and proteins
 Molecular comparisons help us discover and
confirm relationships among species and
lineages