Download Chapter 27 Introduction to Animals Chapter 27 Section 1

Name: _________________________________________________________ Period: ____________
Chapter 27 Introduction to Animals
Chapter 27 Section 1: Characteristics of Animals
General Features of Animals
Number of known animals = Over _________________________ species
Common features all animals share:
1. Heterotrophy
Animals are ________________________
They _______________ make their own food = Must eat other organisms.
2. Mobility
Animals can perform ________________________________________________________.
They move by muscle ___________________________ or shortening.
What are some ways animals move?
3. Multicellarity
Animals have __________________________________________________________.
4. Diploidy
Chromosomes are in ________________________.
One set from the ____________________ and one set from the _____________________.
Advantage = new gene combinations which give rise to variety.
5. Sexual Reproduction
Almost all animals reproduce sexually by producing ______________________ (sex cells).
Our sex cells or gametes are _____________ (female) and _______________ (male).
6. Absence of cell wall
Allows for ___________________________.
7. Blastula formation
Fertilized egg develops
into a hollow ball of
cells with 3 primary
tissue layers.
8. Tissues
All animals except ________________________ have cells arranged into tissues.
Body Symmetry
Refers to an animal’s ______________________________________.
Asymmetrical – ____________________________ in shape
Radial symmetry – body parts arranged around _______________________________________.
Bilateral symmetry – body design in which there are distinct ______________________________
o Cephalization – anterior concentration of sensory structures and nerves (brain)
Internal Body Cavity
Bilaterally symmetric animals have 1 of 3 basic body plans.
o Acoelomates have __________________________________________ or coelom.
o Pseudocoelomates have a body cavity located between the mesoderm and the endoderm.
o Coelomates have a body cavity located entirely ______________________ the mesoderm.
Body Segmentation
Segmented animals are composed of a series of repeating, similar units called ________________.
Ex: earthworm
Crustaceans, spiders and insects show some degree of segmentation, but it may be hard to see in
the adult stage.
_______________________________ (animals with a backbone) do not show segments
externally, but there is evidence of segmentation in a vertebrate _____________________.
Advantages of segmentation:
o Great flexibility and __________________________
o Since each segment repeats many of the organs in the adjacent segment, an injured animal
can still perform vital functions.
o Offers _________________________________________________
Kinds of Animals
Kingdom Animalia (us)
o __________ major divisions called phyla (singular: phylum)
o A phylogenetic tree visually represents the ______________________________ among
various groups of animals based on:

__________________________________________

Comparing the anatomy & physiology of animals

Comparing _______________ in the genes
o The animal kingdom is divided into 2 groups

Invertebrates (animals ______________________ a backbone)

Vertebrates (animals _________________ a backbone)
Chapter 27 Section 2: Animal Body Systems
Tissues and Organs
Tissues - A group of similar ________________ that work together to perform a specific function.
Organ - Two or more types of ________________ working together to perform a specific function.
Body Systems
Digestion
o Single celled organisms and sponges digest their food within their body ______________.
o In simpler animals, there is only ___________opening called a gastrovascular cavity.
o Animals, such as us, have a digestive tract with ________ openings: a mouth and an anus.

This is a ___________________ flow, allowing cells to perform specific functions.
Respiration
o In simple animals, oxygen and carbon dioxide are exchanged directly with the environment
by ______________________________.
o Larger, more complex animals have specialized respiratory structures (_______________).
o Some aquatic (and a few terrestrial) animals breath through __________________.
Circulation
o In simple animals, their cells are __________________________ to the environment or
gastrovascular cavity to obtain oxygen and nourishment.
o Two types of circulatory systems:
1. _______________ circulatory system – heart pumps fluids through vessels into a body
cavity, bathing the tissues. The fluid collects in open spaces and flows back to the heart.
2. _______________ circulatory system – heart pumps blood through a system of blood
vessels
Nerve Impulses
o Nerve cells (neurons) are specialized for carrying ____________________________ in the
form of electrical impulses (conduction).

Coordinate the body activities, allowing the animal to _______________________
________________________.
Support
o Skeleton

Hydrostatic skeleton – consists of ____________________ contained under
pressure in a closed cavity. Ex: hydra and earthworms

Exoskeleton – rigid ______________________ (outer) skeleton that encases the
body of an animal. Ex: insects

Endoskeleton – hard material, such as bone, _________________ an animal (us).
Excretion
o Removal of ______________________ produced by cellular metabolism.
Reproduction
Asexual – __________________________ involve the fusion (union) of 2 gametes.
o Fragmentation – piece of body fragments (breaks off) and the fragment grows into a new
organism.
o Parthenogenesis – new individual develops from an unfertilized egg (bees).
Sexual – new individual is formed from the _________________ of male and female sex cells
o Testes produce ________________ gametes (sperm).
o Ovaries produce ________________ gametes (eggs or ova)
o Hermaphrodites – have _________________ testes and ovaries. But the eggs and sperm
are produced at different times, so self-fertilization does not occur.
o External fertilization – occurs in most aquatic animals. Sperm and eggs are released near
one another in _____________________, where fertilization occurs.
o Internal fertilization – the union of sperm and egg occurs ___________________ the
female’s body.
Chapter 37 Introduction to Body Structure
Section 1: Body Organization
Levels of Cellular Organization
o Human body contains more than 100 trillion cells and more than 100 kinds of cells!
o Levels of organization: Cells → Tissues → Organs → Organ Systems → Organism
Four Kinds of Tissues
o Epithelial tissue:

______________________ the body and ________________ most body cavities

________________________from dehydration and physical damage
o Nervous tissue

Nerve cells (neurons) and their supporting cells

______________________________________________ throughout the body
o Connective tissue

_________________________________________________________ the body

Includes fat, cartilage, bone, tendons and blood
o Muscle tissue 3 kinds that enable movement of body structures by muscle contraction.
1. Skeletal muscle – voluntary (you consciously control it); moves bones
2. Smooth muscle – involuntary (you cannot consciously control it); lines blood vessels
and hollow organs; slow long-lasting contractions
3. Cardiac muscles – involuntary and found in the heart; pumps blood.
Stem Cells
o _______________________________ stem cells are immortal (divide indefinitely) and have
the potential to develop into any type of cell. They offer the possibility of repairing damaged
tissue.
o ______________________ stem cells are not as versatile and are not immortal (most stop
reproducing after fewer than 100 cell divisions).
Organ Systems
Body organs consist of ________________________________ types of tissues working together
to perform a specific function.
Organ systems consist of different organs working together to perform a specific function.
o Circulatory – ______________________________ nutrients, wastes, hormones & gases
o Digestive – _________________________________________ nutrients from food, removes
wastes and maintains water and chemical balances.
o Endocrine – regulates body temperature, metabolism, development and reproduction,
_____________________________________________ and regulates other organ systems.
o Excretory – removes ____________________ from blood and regulates the concentration of
body fluids.
o Immune – ________________________ against pathogens and disease
o Integumentary – (______________) – protects against injury, infection and fluid loss and helps
regulate body temperature.
o Muscular – ____________________ limbs and trunk and substances through the body and
provides structure and support.
o Nervous – regulates behavior, maintains homeostasis, regulates other organ systems and
controls ____________________________________________________ functions.
o Reproductive – produces gametes and ___________________________.
o Respiratory – moves air into and out of the lungs and controls _______________________
________________________ between the blood and the lungs.
o Skeletal – _______________________________________________ the body and its organs,
interacts with skeletal muscles to provide movement, and produces red and white blood cells
and platelets.
Body Cavities – house and protect major organs
Thoracic – contains the ______________________________________
Cranial – contains the _________________________
Abdominal – contains the _____________________ organs (stomach, gall bladder, liver, pancreas)
Spinal – down center of back, holds ________________________________________________
Endothermy
•
Humans are endotherms, like all mammals.
•
Humans maintain a temperature of 37◦C (_____________◦F)
•
The human body uses a great deal of ___________________ to maintain a stable internal
condition.