M1: L3: Animal Characteristics and Development

When did life first formed?

about 3.5 BYA

When did the two other kingdom (eukarya and archae) formed?

about 3 BYA

When did animal first formed?

about 700 MYA

What are the characteristics of animals?

multicellular eukaryotes

2) heterotrophic

3) sexually reproducing

4) highly mobile (in at least 1 stage of life)

5) have tissues

a) muscle

b) nerve

T/F - Muscle and nerve tissues is not unique to animals.

false

define tissues.

specialized cells that func tgt

T/F - Sponges do have tissues.

false

T/F - Cnidarians have tissues.

true

How many tissues do cnidarians have?

diploblastic

how many tissues do other animals have besides the sponges and cnidarians?

triploblastic

What are the 3 tissue layers?

ectoderm becomes the outer covering (epidermis)

endoderm becomes the digestive tract

mesoderm becomes the muscle and most of the other organs

What are the stages of animal development?

zygote —> cleavage: 2 cells —> 4 cells —> 8 cells —> morula (solid ball) —> blastula (hallow ball) w a blastocoel —> gastrulation: gastrula w blastopore —> formation of the endoderm, ectoderm, and archenteron —> archenteron becomes the gut

define cleavage.

a form of mitosis where identical copies of cells are made 

define acoelmate

mesoderm is tissue filled all the way

define coelomate.

mesoderm has a coelom (some empty space)

define pseudocoelomate (hemocoel).

mesoderm does not encase the entire body cavity opening

What makes up the muscle?

a bundle of muscle fibers —> a single muscle fiber —> a single cell with nuclei —> surrounded with p.m —> made of myofilaments

define sacromere.

a contractible, functional unit

What are the two types of muscle filments?

actin and myosin

T/F - When muscle contracts, the sarcomere elongates.

false - it shortens