Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Why study zoology?
Animals spread disease, give us medical resources, agriculture, food, help with drug testing
...

Humans love animals
...
Ex, platypuses came from other groups,
which is why they lay eggs, however, they also have mammalian characteristics
Monophyletic​: a single common ancestor gives rise to a group of organisms

Systematic schools
Numerical taxonomy (Phenetics)​: all classifications have no reality in nature
Phylogenetic systematics (Cladistics)​: all groups are real
Evolutionary taxonomy (neodarwinism​): Species is the only real group
...

Species​: group of interbreeding natural populations that are reproductively isolated from other
groups
...


Evidence to construct a phylogeny
Finding evidence of former species can help trace how current species exist
This doesn’t always work, however, because it’s hard to know if you find every species in
between
...
Finally, mistakes can be made
when putting bones together
Ex, brontosaurus isn’t real
...

Now, we can use genetics and biochemistry to try to connect past species to present ones
...
Counting the number of chromosomes can help connect species
...


Ontogeny can also help, looking at species from when they are fetuses to when they die
...
We can
compare behavior

Comparative anatomy
1
...
Homology-analogy
In homology, we have evolutionary similarity
...

These were derived from a single common ancestor
Analogy is functional similarity
...
However, there is no common ancestor to give two species the same traits
...
ex) snakes and glass
lizards
Convergent evolution:​ analogy without homology
Divergent Evolution​: Homology without analogy
Parallel evolution​: Analogy and Homology, but with
separate or independance evolutions
ex) two rodents that look and function exactly the
same, but have different evolution
...
Independently, the two types of
rodents then evolved to have traits such as long tails
with a puff on the end and large ears
...
ex) class, order, family,
species
Taxon​: refers to a specific group by name
...
Naming the
genus and species together is called binomial nomenclature)

This naming of species was developed by Linnaeus
In between phylum and class, there is something called superclass
...
These prefixes can be added to any of them
...
He simply put together pieces that other scientists
already thought about
...
Not the concept
...
It hadn’t been discovered yet
...

Synthetic theory​: the combination of Darwin’s theory and our current knowledge of genetics
...

Struggle for survival due to limited resources
Some individuals have a better chance for survival than others
Natural selection acts to weed out certain individuals which are not genetically fit

Natural selection acts at the level of the individual
...

So what is evolution?
Evolution is life in the 4th dimension
...

Here’s a better definition:
Evolution is a change in the genetic composition of populations
Evolution is the interaction between populations and their environments, where the
consequences of the environment are to
● Go extinct
● Remain unchanged
● Evolve adaptations
Adaptation​: represents those characteristics possessed by an organism that enable it to survive
and increase fitness
...
8% of the people living in his former empire may
have some of his genes
...

What is the pace of evolution? Macroevolution is rapid change, with large scale events in
organic evolution
This depends on whether it is microevolution (small changes in gene frequency) or
macroevolution (large changes in only a few steps)
Frequency of alleles of genes possessed by members of the population (i
...
, gene pool) will
remain unchanged and constant unless disturbed by new mutations, natural selection, or
genetic drift (i
...
by chance)
...

Directional selection​: favors one side of the spectrum, so evolution happens in a specific
direction
Disruptive selection​: both of the extremes are preferred, so the middle is selected upon
...
major groups
appear that are new
Punctuated equilibrium​: new species emerge suddenly and remain mostly unchanged until they
become extinct
...

The first life forms, prokaryotes, showed up about 4
...
Cyanobacteria were the
most important, because they went through photosynthesis (so they can make their own food)
...


Great Oxidation event
●
●

2
...
8 billion years ago
Eukaryotes show up
...
Most importantly, they
brought in sex
Hypersex (endosymbiotic organisms)
Rather than dividing organisms, this fuses organisms, creating new entities
...

Commensalism: one organism benefits, the other is neutrally affected (ex: e
...
They don’t affect us, but we help them
...


Multicellularity
Evolution of animals
800 million years ago
First fossils 650 million years ago
Many theories on how this arose
...
In plants, animals, and fungi, it
happened separately

First theory: Amalgamation/ colonial hypothesis
Individual cells start to group together and begin working different jobs (specialization) certain
cells take on certain functions
...
They are simply better at some function than the cells around it
...
Now the cells are dependant on each other

Another theory is compartmentalization/ plasmodial hypothesis
One cell starts off, then grows bigger and bigger
...
The nucleuses then from barriers around themselves, this
creating new cells
...
Rather than becoming individuals, the
cells stay attached to each other, creating a multicellular organism
...
The bigger the body, the more materials and resources needed to feed
the body
...

Surface area+supply
Metabolic rate+mass
This makes it difficult to nourish larger cells
...

Early on, 542 million years ago, the cambrian explosion occurred and lasted 20 million years
...

Sponges began to develop internal skeletons
...
These hard spicules gave support
Skeletons could also be built of fibers called Spongin fibers
...

Nyderians created what was called a hydrostatic skeleton, which was made by the absorption of
water increasing pressure, which allows the creature to stand due to stiffness and rigidity
...
These are flat
Leuconoid​- much more complex, they contain channels to allow the water in
Choanocytes​ are flagellated parts of the sponge to bring water into the body
...
Amoebocytes distribute the food around the body
Diploblastic​:two layers of cells; two types of cells in the design of a body
Radial symmetry​: when divided down the central axis, all pieces are equal, regardless of what
plane it is cut on
...
This lengthens the body, and allows species to move faster
...
This causes sensory organs to be put on specific parts of the body, because movement
is generally in one direction
...

2
...
Basically, brains are made now
...

Polymorphism​: throughout an organism’s life, they go through different body symmetries
...
Base is on the bottom attached to the
ground
● Medusa​: mouth is on the bottom, tentacles surround
This happens to jellyfish and other creatures
...

This is called ​paedogenesis
...


Along with bilateral symmetry, species become ​triploblastic​, meaning that they now have a third
layer of cells
...

These layers are called germ layers
...
Muscle, reproductive and excretory systems
...
This is called the coelom
...
This holds all of the internal organs
...


Functions
●
●

greater freedom of movement, due to not being completely solid
Development and differentiation of organs, due to having space to make them more
complex

●
●
●
●

Circulation within the body, due to the addition of a fluid
...
This motion can aid
burrowing into sand and mud
...
This lining lines true
coeloms
...
Rotifera and gastrotricha are other examples
...


Protostomes
●
●
●
●

Schizocoelous​: type of
embryo development
Blastopore becomes mouth
Spiral cleavage
Determinate embryology- the
cells are pre programmed to
become a certain structure,
regardless of where they are
in the body (ex, beak on the
buttocks)

Deuterostomes
●
●
●
●

Enterocoelous​ type of
embryo development
Blastopore becomes anus
Radial cleavage
Indeterminate embryology​:
the cells don’t have a predetermined structure
...

Protostomes include organisms like worms, snails, slugs, mollusks,
insects, annelids, arthropods
Deuterostomes​: Vertebrates, echinoderms
...
They all have very similar features with
only slight variation
...
It has tiny teeth and muscles that can be everted outside of the mouth
The largest group of molluscs are the gastropods, which are like snails, abalone, ect

Torsion​: twisting of the body
...
Why do
this? The shell of a twisted body is much safer tan a body with a non-twisted shell
...

Nudibranchs:​ means naked gills, they don’t have full shells, and look beautiful
...
These creatures have two shells to cover the whole organism
...
If you cook a clam and it doesn’t open, that means it
was dead before it was cooked
...
If it doesn’t open, they didn’t ‘relax’, meaning it was dead
...

The last group is the ​cephalopoda​: the muscular foot has fused with the head of the anima
...
The largest molluscs are in this group (Example: giant squids)
...
They have beak like jaws to rip at their prey
...
Their shells are broken up in 8 dorsal plates
...
They are interesting when they are turned onto their back
...

They have many gills that repeat themselves around the
body
...
Their bodies are split up
into repeated segments
...

● ​The polychaeta​: these are aquatic
...
They live in the tube for the majority of
their lives

●

Clitellata​: earthworms
...
Leeches are another example of these
worms
...
The body segments repeat
...
This helps incase the worms are squeezed
...

In order to get movement, there must be coordination between the segments
...
This is like a wave of muscle contraction
...
With more
elaborate nervous systems comes more elaborate behaviors
...

This group is called the ​Arthropods

●
●
●

●

●
●

they have reduced the number of body segments, though they still
are segmented
They have grouped these segments into functional groups (EX:
bugs have three main sections)
Biramous appendage: 2 branges to any appendage
...
This basic structure allows for the building of
different appendages for different functions
...
Mosquitos drink our blood with an appendage
...
This shell
protects them
...
It is a nitrogen
polysaccharide that makes the hard structure
...

The appendages have flexible joints to allow for a
greater range of movements for the hard skeleton
...
(examples: cicadas

shedding their shells, Mr, Krabs in that one episode of spongebob sheds his shell) This
is called Ecdysis
The Arthropods have greatly diversified
Pillbugs are land-dwelling crustaceans

---