B2.3 Flashcards
What is the fossil record?
The way the Earth is shown by fossils from different periods of time
What is evolution?
When organisms change gradually overtime
What are the 3 main reasons for gaps in the fossils records?
- fossils do not always form
- soft tissues decay
- many fossils have not been found yet
Why does the fact that fossils do not always form leave gaps in the fossil record?
The fossils do not always form so they can be discovered which causes gaps in the fossil records
Why does the fact that soft tissues decay leave gaps in the fossil record?
The soft tissue decays and does not always form fossils so there is little fossil evidence left behind causing gaps in the fossil records
Why does the fact that many fossils have not been found leave gaps in the fossil record?
The fossils have not been found and so can’t be filled in which causes gaps in the record
What is the problem with having gaps in the fossil record ?
Scientist have to interpret what the organism looks like which are often incorrect
What is a pentadactyl limb?
A basic five fingered limb
What does many vertebrates having pentadactyl limbs help to prove?
It helps to prove that all vertebrates have evolved from a single vertebrate, millions of years ago
Name all of the bones present in a pentadactyl limb
- humerus
- radius
- ulna
- carpals
- phalanges
What is growth in an organism?
When an organism increase in size, length or mass
What is it called when plant cells get longer?
Elongation
Why do plant cell differentiate?
If the are old they will differentiate and become different cells
What is the difference between animal and plant growth?
Animal growth involves cell decision and not elongation it also stops when the animal becomes an adult
What is the name of the cell formed when cells in an animal differentiate to form a number of different type of specialised cells?
A stem cell
What are the 4 components in blood?
- plasma
- red blood cells
- white blood cells
- platelets
What is plasma?
It’s a yellow liquid that transports dissolved substances, such as carbon dioxide, food substances and hormones
What do red blood cells do?
They contain the red pigment haemoglobin which can combine reversibly with oxygen to form oxyhemoglobin
What are fossils?
The preserved traces or remains of organisms that lived thousands or millions of years ago
Where is oxyhemoglobin created and what is it used for?
It is created in the lungs (combination of oxygen and haemoglobin) it is used to provide oxygen for tissue for aerobic respiration
Describe the shape of a red blood cell
It has a bio concave shape which means that it has a dimple on both sides to allow for a larger surface to volume ratio.it also has no nucleus which makes as much room for haemoglobin as possible.
What do white blood cells do?
They help us to defend against diseases. Some white blood cells create microorganisms. These are proteins that bind to the microorganism that cause disease and kill them
What is the difference between red and white blood cells?
White blood cells have a nicleus
What are platelets and what do they do?
Platelets are tiny fragments of cells, they are used in the creation of a blood clot. A blood clot will dry out and form a scab which will prevent any blood from leaving your body and will prevent any microorganisms form entering your body
What is an organ?
An organ contains several different types of tissue that work together to carry out a particular function in the body
What is deoxygenated blood?
When a red blood cell is lacking in oxygen in becomes deoxygenated
What is oxygenated blood?
When red blood cells inside of blood are full of oxygen
How does the body make deoxygenated blood oxygenated?
Deoxygenated blood in pumped by the heart to the lungs where they haemoglobin in red blood cells picks up oxygen and the blood becomes oxygenated. This oxygenated blood then goes back to the heart and is pumped around the body to the tissues and cells.
List all of the parts of the heart
- aorta
- superior vena cava
- pulmonary artery
- pulmonary veins
- left atrium
- right atrium
- left ventricle
- right ventricle
- inferior vena cava
- valves
- tendons
- septum