B6 Flashcards

Question

What are the 2 causes of variation within a species?

Answer 1

Genetics and the environment.

Answer 2

1. Gradual replacement by minerals - body parts such as teeth, bones and shells decay really slowly → meaning they can be replaced with minerals whilst decaying and form rock like substances which are in the exact same shape and size as the original structures → when dug up and separated from rock, we are left with perfect the model. 2. Casts and impressions (similar types of fossils) - casts → organisms are buried in soft material (e.g clay), as clay hardens the organism decays → left with a gap that is the same size and shape as the organism - impressions → when organisms leave a mark on the ground that stays there for time ( e. g footprints ) 3. Fossils can be formed by preservation when no decay happens at all.) - when organisms get stuck in amber or tar pits → because there is no oxygen on moisture, no decay can take place so organism remains completely intact - also happens in glaciers where it is too cold for microorganisms that normally carry out the decay process to survive or in peat bogs where it is too acidic for microorganisms.

Answer 3

l. Many early life forms where soft bodied so would have decayed quickly making any fossil remains unlikely 2. Fossils formed long ago where destroyed by earthquakes and volcanos.

Answer 4

1. Environment changes too quickly ( e.g. Too hot /too cold) 2. New predators, including humans. 3. New diseases → kills them all

Answer 5

A homozygous recessive (ff) genetic disorder Results in the body producing a lot of thick sticky mucus in the air passage and in the pancreas.

Answer 6

1. chest infection 2. Low energy levels 3. Sticky mucus

Answer 7

A dominant genetic disorder that causes babies to be born with extra fingers/ toes.

Answer 8

1. Mother is given hormone (fsh and lh) to stimulate many eggs to be produced 2. Eggs are collected and fertiliseel using sperm from father. 3. Fertilis ed eggs are allowed to develop into embryo is and one cue from each embryo is removed. 4. These alls are tested for the allele linked with the disorder 5. Embryos which do not have the allele allele are implanted into the mother's womb, other embryos may be destroyed

Answer 9

1. Babies would be born tree of the disorder screened for 2. Avoids costs of large long -term treatment

Answer 10

1. many more embryos than needed are erected → which means they will usually be destroyed 2. Some disorders are not life shortening 3. Could lead to negative perceptions and feelings about disability.

Answer 11

1. Cost of screening 2. Raising child with disorder 3. Lower medical bills

Answer 12

1. Healthy sibling may feel neglected or have to help look after sibling 2. Parent lifestyle.

B6 Flashcards

(38 cards)