Download Grade 9 Science – Unit 1 – Biology

Grade 11 University Biology – Unit 1 Diversity
How are species related?
Section 1.2 – Pages 17-23
Classification needs to include morphology and phylogeny. This is accomplished with the concept of
shared evolutionary history (i.e., organisms sharing an evolutionary history are related).
Ancestor – An organism (or organisms) from which other groups or organisms are descended.
Evidence of evolutionary ancestry is based on three types of evidence: (1) anatomical, (2) physiological
and (3) DNA. This information is compared with the same information for other species and the
evolutionary lineage is determined.
Anatomical Evidence of Relationships
 Anatomy is the branch of biology that deals with
structure and form, including internal systems. Recall,
morphology refers to body size, shape and physical
features to learn how an organism develops and
functions structurally. Anatomy is a branch of
morphology.
 See Figure 1.6 – Page 18 to learn how some dinosaurs
and modern birds are anatomically related. As well, the
two illustrations opposite some the foot of a
Tyrannosaurus rex and a bird. Both have three forward
toes and one toe facing back. As well, there are “claws”
on all toes.
 Another comparison is the anatomical similarities among
living species. As shown in Figure 1.7 – Page 18, four
Animalia species – whale, bat, horse and human – have
similar internal bone structures. The size of proportion
of the bones have been modified by purpose (i.e.,
swimming, flying, running and grasping, respectively);
yet, the arrangement and similarities suggest a common
evolutionary history.
Physiological Evidence of Relationships
 Physiology is the branch of biology dealing with the physical and chemical functions of
organisms, including internal processes. Physiology includes how organisms, organ systems,
organs, cells and biomolecules carry out the chemical or physical functions that exist in a living
system.
 By comparing these processes, the degree of genetic similarity can be assessed.
DNA Evidence of Relationships
 Genes are section of DNA made of long chains of molecules
called nucleotides. Sequencing of nucleotides is possible via
gene mapping. Once a sequence is determined, it can be
compared to the DNA of other organisms to assess similarities.
 As noted in Figure 1.10 on Page 20, DNA evidence has
produced some surprising results. For example, fungi are more
closely related to animals than plants.
Phylogenetic Tree
 A branching diagram used to show the evolutionary
relationships among species. Illustration show links between
humans and apes (LCA = Last Common Ancestor)
Task


Compare the skeleton of a bird and a dinosaur
Identify similarities which may link their evolutionary history.