The Animal Kingdom Contains

– 99% of all animal species are __

• Animals diverged from fungi as far back as 1.5 billion years ago

• Common ancestor of all animals may have resembled modern __.

– Protists that are the current closest living relatives of animals

The Animal Kingdom:

Have a __ and posess a collar of __ for trapping food.

Similiar cells also found in cnidarians, flatworms, and echinoderms

Body Plans: 

Set of morphological and developmental traits

• Symmetry – three types

1. __ of symmetry

• ex. sponges

2. __ symmetry

3.  __ symmetry

Radial Symmetry:

– Animals that are symmetrical around a

central axis

• seastars, sea urchins, jellyfish

– Have a top ( __ ) and bottom side ( __ )

– Any __ slice through the __ axis

divides the animal into __ images

– Typically are sessile, slow moving, or planktonic.

Bilateral Symmetry:

– Only __ vertical cut divides the animal into mirror images

• Animals have:

– A __ (top) side and a __ (bottom) side

– A right and left side

– __ (head) and __ (tail) ends

– Cephalization = the development of a __ (brain, eyes, ears)

– Tend to be more __ in their movements

Reproduction and Develpoment:

• Most animals reproduce sexually

• After fertilization, the diploid zygote undergoes rapid mitotic cell division called __.

• Cleavage leads to formation of a __.

– In most animals is a __ ball of cells

– Internal opening is the __

• The blastula undergoes __

– inward folding at one end of the embryo

– Forms into a __ with different layers of embryonic tissues

Germ Layers:

• Layers of cells in the gastrula that differentiate (develop) into different types of tissues and organs

• In a gastrula

– Fluid-filled space = __ (early gut)

– Outer layer = __ 

– Inner layer = __

– Cells that migrate between two layers = __

Germ Layers:

• Diploblastic animals have only __ and __

– Jellies and corals

• Triploblastic animals have all __ germ layers

– All bilateral animals (symmetry)

• Most triploblastic animals possess a coelom = a __-__ body cavity

– A true coelom is derived from __

Body Cavities in Triploblastic Animals:

• Functions of a body cavity

– Fluid helps to __ your organs

– Isolates the organs from the walls of the body

– In soft-bodied animals the fluid-filled cavity acts as a __ __.

• Coelomates are animals that possess a _ __

• Pseudocoelomates have a body cavity that is formed between the __ and __

• Acoelomates __ a body cavity

protostome

deuterostome

• Two types of development for triploblastic animals

• Protostome development:

– Cleavage is spiral = cells in layers that are offset by __

– Determinate = each cell has a determined fate __ in development

– Schizocoelous = initially solid masses of __ split, forming the body cavity

Deuterostome development:

– Cleavage is radial = cells lined up on top of each other

– Indeterminate = each cell in the early stages of cleavage __ the capacity to develop into a complete embryo (stem cells)

• Identical twins

– Enterocoelous = mesoderm buds from the wall of the __ to form the coelom

know differences!! 

where does the mouth and anus develop?

Fate of Blastopore

• The blastopore forms during gastrulation

– Opening in the __ to the exterior of the gastrula

• In protostome development, the blastopore becomes the __

• In deuterostome development, the

blastopore becomes the __

Animal Phylogeny:

• Zoologists recognize about three dozen animal phyla

• Relationships between phyla are debated

• Two main phylogenetic hypotheses one based on __, the other based on __ data

• Points of agreement

1. All animals share a __ ancestor (monophyletic)

2. __ are basal animals (lack true tissues) 

3. Eumetazoa is a clade of animals with __ __ (all animals except for sponges and a few other groups)

4. Most animal phyla belong to the clade __

5. Chordates and some other phyla belong to the clade __

Animal Development:

• Development = changes in structures or proportions related to __

• Often juvenile organisms resemble adults

• However many animals have at least one larval stage

– A larva is sexually __ stage and morphologically distinct from the adult

– Eventually undergoes __

• All animals, and only animals, have __ __that regulate the development of body form

– Control __ __ and __

Animal Body Size and Shape:

• Many different animal body plans have evolved in animals

• Factors influencing body size and shape:

1. Surface area to volume ratios

• Surface area = amount of __ an

organism has

• Volume = amount of __ __ an

organisms has

• As an organism gets bigger, the surface area increases more __ than the volume

Animal Body Size and Shape:

• A small organism has more __ __ relative to its __. (higher ratio)

The bigger you are the __ your ratio

Surface Area to Volume Ratios:

• Influences how animals interact with their environment (take in food, regulate internal [H₂O], temp. regulation)

• Tiny animals (hummingbird, shrew)

• Very high surface area to volume ratios

• __ a lot of body heat to their surroundings

• Eat __

• Can undergo bouts of __ to reduce

metabolic demands

Gravity:

• As animals get larger they need to be __ to support their weight (thicker legs, skeletons)

• Also as size increases, __ __

increases to allow heavier animal to move around

Medium:

• Water is much more __ and __ than air

– Animals experience a lot of drag when moving through water (streamlining)

– Very __ = supports the weight of animals (do not need __ skeletons)

• Can get very large! (whales)

__- upward force exerted by a fluid that opposes an objects weight

Medium:

• Air

– When moving, experience less __

than in water (streamlining not required,

unless __ moving or __)--chetah, bird

– Not much __, no bouyancy (need greater structural support - skeletons or something similiar- to counteract gravity

Hydrostatic Skeletons

• Consists of fluid held under pressure in a closed body compartment

– Use muscles to change the shape of the fluid-filled compartment to move

• This is the main type of skeleton in most cnidarians, flatworms, nematodes, and annelids

• Annelids use their hydrostatic skeleton for __

– A type of movement on land produced by rhythmic waves of __ __ passing from front to back

Variation in White-tailed Deer Mass:

• Largest in Canada & N. US (136 kg)

• Kansas (93 kg)

• Louisiana (60 kg)

• Florida Keys (23 kg)

Bergmann's Rule: Body mass increases with __