Invertabrates 1

Question 1

What types of organisms are Eukaryotic?

Answer 1

-Fungi
-Cillia
-Plants
-Animals

Question 2

What does Eukaryotic mean?

Answer 2

Contains eukaryotic cells with a true nucleus and organelles specialized for specific functions

Question 3

What does heterotrophic mean?

Answer 3

An organism that obtains carbon by consuming another organism

Question 4

What organisms are heterotrophic

Answer 4

-fungi
-protists
-prokaryotes
-plants
-Animals

Question 5

What is multicellularity?

Answer 5

An organism composed of many cells

Question 6

Advantages of multicellularity?

Answer 6

1. Cells can be specialized to complete specific functions (ex. nerve cells, muscles cells)
2. Organism can be large. In multicellular organism as cells increase inside they must undergo mitosis because if they don’t their volume to surface area ration would be bad and they wouldn’t be able to absorb enough nutrients to maintain their volume.
   3.Cells can form tissues. Tissues are a group of cells organized into a functional unit. (nervous tissues, muscle tissues)
3. Tissues can then come together to form organs

Question 7

What do animals have instead of a cell wall?

Answer 7

A skeleton is found in animals to maintain their shape

Question 8

What is a hydrostatic skeleton?

Answer 8

A skeleton found in soft bodied organisms (cnidarians and worms)
How it works: gut filled with fluid, provides structure and shape to the organism

Question 9

Advantages and disadvantages of a Hydrostatic skeleton?

Answer 9

Adv: Organisms can perform simple but efficient movements
Dis: limited to wet environments because they must continuously replenish their fluids and limited possibility for the attachment of limbs(does not have spots for them)

Question 10

What is an Exoskeleton

Answer 10

Found in shelled mollusks and arthropods, it is a firm rigid structure outside of the body.

Question 11

Moulting

Answer 11

-Exoskeletons do not grow with the organism
-Organisms with exoskeletons thus go through a process called moulting where they shed their exoskeleton

Question 12

What is an endoskeleton?

Answer 12

Found in sponges, echinoderms and vertebrates it is found inside the organism and is made up of rigid structures. In humans the endoskeleton is made up of living tissues(bones(connective tissues)). In invertebrates the endoskeleton can be made up of non living tissues(sponges(spicules))

Question 13

Motile at some life stage

Answer 13

Animals are motile at least one time during their lives(barnacles are not motile as adults however they are motile as larvae)

Question 14

Why is motility advantageous?

Answer 14

-motility reduces competition(easier to catch food and find food when you can move)
-Enhances genetic diversity because of migration

Question 15

What are somatic cells?

Answer 15

Cells that contain two types of each chromosomes(one from the mother and one from the father)

Question 16

Why are somatic cells advantageous?

Answer 16

-Diploid stage dominates
-Double the DNA means more genetic diversity, also if you have a mutated gene from one parent it is possible that the second copy of the gene from the other parent that is not mutated can mask the mutation.

Question 17

What does it mean when an organisms diploid stage dominates over the haploid stage?

Answer 17

The organism is diplontic

Question 18

Name the 7 characteristics of animals?

Answer 18

1. Eukaryotic
   2.Multicellular
   3.Heterotrophic
   4.Diplontic
   5.Somatic Cells
2. No cell wall
3. Motile at some life stage

Question 19

Cambrian Explosion

Answer 19

Emergence of a wide variety of animals on earth. First animals to appear sponges and corals

Question 20

Monophyletic

Answer 20

Animals are monophyletic meaning they evolved from one common ancestor and have many of the same characteristics.

Question 21

Evidence that animals are monophyletic

Answer 21

1. Similar gene sequences
2. Similar extracellular matrix molecules
   3.Unique types of junctions among cells

Question 22

How do similar gene sequences prove monophyly?

Answer 22

Hox Genes
- Genes that give each segment on an organism an identity and tell it what structures it should grow
-Proves monophyly because how genes can be found in many animals

Question 23

How do similar extracellular matrix molecules prove monophyly?

Answer 23

-Found in animal cells provides structural support and controls communication among cells
-Contain Proteins and proteoglycan complexes

Question 24

How do unique types of junctions among cells prove monophyly?

Answer 24

Most animals have junctions among their cells proving that they share similar traits and are monophyletic.

Question 25

What is a cell junction?

Answer 25

Something that connects a cell to another cell

Question 26

What is tight junction? Where does it occur?

Answer 26

Tight junctions connect two cells together so tightly it is like a watertight seal.
Occurs in the epithelial tissue in the lining of the stomach and intestine(a place where we don’t want fluids to leak out)

Question 27

What is a desmosome? Where does it occur?

Answer 27

Connect the cytoskeleton of cells together(not watertight)(things can flow between the cells). Occur in epithelial tissue

Question 28

What is a gap junction? Where does it occur?

Answer 28

Connects two cells together by a channel. Found in nerve and muscle tissues in which rapid communication between cells is most important.