Vertebrates And Invertebrates

Question 1

How do scientist place vertebrates into groups based on oxygen absorption methods?

Answer 1

One characteristic- way they absorb oxygen for respiration

• Fish have GILLS to absorb oxygen in water.
• Young amphibians also have GILLS
• Adult amphibians have LUNGS and can absorb oxygen through their moist skin
• Mammals/reptiles/birds have LUNGS

Question 2

How do scientist place vertebrates into groups based on reproduction?

Answer 2

• External fertilisation; where the female adult releases her eggs into the water where they are fertilised by the sperm release by an adult male
• Internal fertilisation; where the sperm is placed inside the female- takes place inside her body.
• Oviparous; many vertebrates in this group then lay eggs
• VIviparous; mammals give birth to live young.

Question 3

How do scientist place vertebrates into groups based on thermoregulation?

Answer 3

• Homeotherms; means that they keep their body temperature mor constant, and often warmer, than their surroundings by releasing heat from reactions in their body
• Poikilotherms; means that their body temperature varies with the temperature of their surroundings.

Question 4

Describe the main characteristics of the phylum Chordata as animals with a supporting rod running through the length of the body.

Answer 4

The backbone in vertebrates

Question 5

Demonstrate an understanding of the problems associated with assigning vertebrates to a specific group based on their anatomy and reproduction methods and why many vertebrates are difficult to classify.

Answer 5

Within a group some species have different characteristics to the rest of the group. Examples;
-A few amphibians have gills even as adults.
-Sharks are fish but use internal fertilisation, and some give birth to live young.
You have to look at many characteristics to help decide which group an organism belongs to.

Question 6

Define Chordata

Answer 6

They have a supporting rod which runs the length of their body