, Definitions
• Evolution: a gradual process in which life forms change over time
• phylogenetic tree: a branching diagram showing the inferred evolutionary relationships between species
• body plan: the plan for the way the body of an organism is laid out
• Asymmetrical: referring to a body plan that has no axis of symmetry
• Sessile: animals permanently attached to a substrate (e.g. a rock)
• Radial symmetry: body parts arranged regularly around a central axis of symmetry.
• Longitudinal: along the length (of an animal in this Case)
• bilateral symmetry: the configuration of a body that can be divided longitudinally into two halves that are mirror images
• Motile: capable of independent locomotion
• Anterior: the head end
• Posterior: the end opposite the head
20XX presentation title
, Definitions
marine: living in sea water
cephalisation: an evolutionary trend in the animal kingdom toward centralisation of neural and sensory organs in the head or
anterior region
of the body
germ: (germinal) layer produced by embryonic development of different kinds of cells
mesoderm: the middle layer of cells in triploblastic animals
specialised: has a structure with a particular function
diploblastic: describing animals formed from two germ layers
mesoglea: a middle layer of a jelly-like material in diploblastic animals
triploblastic: describing animals formed from three germ layers
coelom: a body cavity formed by a split in the mesoderm
acoelomate: animal without a body cavity
Dorsal: human body, dorsal (i.e., posterior) refers to the back portion of the body
Ventral: ventral (i.e., anterior) refers to the front part of the body.
20XX presentation title
,Phyla
Grouping
, Kingdom Animalia
• The Kingdom Animalia can be divided into two main groups:
• Invertebrates – animals without a vertebral column
• Vertebrates – animals with a vertebral column
• The vertebrates and invertebrates can be subdivided into phyla according
to shared characteristics. The six phyla that you need to know in Grade
11 are: Phylum: Porifera e.g. sponges
• Phylum: Cnidaria e.g blue bottles, jelly fish, sea anemones Phylum:
Platyhelminthes e.g. tapeworms, Planaria Phylum: Annelida e.g. earth
worms
• Phylum: Arthropoda e.g. crab, spider, locust
• Phylum: Chordata e.g. fish, mammals, birds, reptiles, amphibians.
20XX presentation title
, How to remember classification
20XX presentation title
, Origins
• origins of animals have been debated by zoologists and biologists.
• Evolution is a gradual process that causes change in the inherited characteristics in a
population across successive generations. It is believed that all animals evolved from a
common ancestor. The classification of animals into groups is based on the evolutionary
histories of the various animal groups. Each group has a common ancestral origin,
which determines the basic structure and some of the behaviour of the animals in each
species. If you look at the limbs of amphibians, reptiles, birds and humans, you will see
that they all have a similar basic anatomy.
• This suggests that they evolved from a common ancestor.
How to read phylogenetic tree:
• The tips of the branches represent the species in the different phyla. The common point,
where a branch divides, represents the common ancestor of two or more phyla.
• Can you see that sponges (phylum Porifera) share a more ancient common ancestor
with an earthworm (phylum Annelida) than the earthworm shares with a snail(phylum
Mollusca)?
20XX presentation title
, From common
ancestor
• Over time, each animal phylum evolved a
unique body plan in which tissues and org
carried out their basic functions. The anim
groups are defined, in part, on the basis o
their body symmetry and body plans. A bo
plan is the way in which an animal's body
laid out. Many animal phyla became extinc
but 30 phyla survived to the present day. Y
will study six of these animal phyla in this
Porifera (e.g. sponges), Cnidaria (e.g. jelly
sea anemones and coral), Platyhelminthes
(e.g.
• "flatworms and tape worms), Annelida (e.g
earthworms), Arthropoda (e.g. insects, cra
spiders and centipedes) and Chordata (e.
fish, amphibians, reptiles, birds and mamm
20XX presentation title
, Key Features of Body Plans
Symmetry
• The body plans of animals show different patterns of body symmetry. Symmetry re
to an imaginary line or plane that could divide the organism into similar-looking halv
that are mirror images. Figure on next slide shows some of the different types of
symmetry found in the body plans of animals.
• Animals that show no pattern of symmetry are asymmetrical. Asymmetrical animals
no general body plan or an axis of symmetry that divides the body into halves that
mirror images. These animals are sessile. Sessile animals are permanently attached to
substrate such as a rock and so can stretch out in all directions from the centre.
• Radial symmetry means that the body parts of an animal are arranged so that any
longitudinal plane divides the animal into halves that are almost identical mirror imag
Examples of animals displaying radial symmetry are jellyfish and sea anemones. Anim
with radial symmetry tend to be sessile. Jellyfish have a radial symmetry, but are not
sessile. Radial symmetry allows the animal to reach out in all directions.
20XX presentation title
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller kayladamon36. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.20. You're not tied to anything after your purchase.