Back to AI Flashcard MakerBiology /Biology IB HL - 5.1 Evidence for Evolution Part 3
What are homologous structures?
Anatomical features that are similar in basic structure despite being used in different ways are called homologous structures
Tap or swipe ↕ to flip
Swipe ←→Navigate
1/28
Key Terms
Term
Definition
What are homologous structures?
Anatomical features that are similar in basic structure despite being used in different ways are called homologous structures
What does it mean if the homologous structures of two species are similar?
The more similar the homologous structures between two species are, the more closely related they are likely to be
What do homologous structures indicate? Give a definition
Homologous structures illustrate adaptive radiation, whereby several new species rapidly diversify from an ancestral source, with each new species ada...
What is an example of homologous structures?
A classical example of homologous structures is the pentadactyl limb in a variety of different animals
What organisms share the pentadactyl limb?
Mammals, birds, amphibians and reptiles all share a similar arrangement of bones in their appendages based on a five-digit limb
How may animal limbs differ?
Despite possessing similar bone arrangements, animal limbs may be highly dissimilar according to the mode of locomotion:
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
What are homologous structures? | Anatomical features that are similar in basic structure despite being used in different ways are called homologous structures |
What does it mean if the homologous structures of two species are similar? | The more similar the homologous structures between two species are, the more closely related they are likely to be |
What do homologous structures indicate? Give a definition | Homologous structures illustrate adaptive radiation, whereby several new species rapidly diversify from an ancestral source, with each new species adapted to utilise a specific unoccupied niche |
What is an example of homologous structures? | A classical example of homologous structures is the pentadactyl limb in a variety of different animals |
What organisms share the pentadactyl limb? | Mammals, birds, amphibians and reptiles all share a similar arrangement of bones in their appendages based on a five-digit limb |
How may animal limbs differ? | Despite possessing similar bone arrangements, animal limbs may be highly dissimilar according to the mode of locomotion: |
What are human hands adapted for? | Human hands are adapted for tool manipulation (power vs precision grip) |
What are bird and bat wings adapted for? | Bird and bat wings are adapted for flying |
What are horse hooves adapted for? | Horse hooves are adapted for galloping |
What are whale and dolphin fins adapted for? | Whale and dolphin fins are adapted for swimming |
What variation will be present in a population of a species? | Within a population of any given species there will be genetic variation (i.e. variation which is inheritable) |
What will genetic variation follow? (dis/continous + distribution) | Typically this variation will be continuous and follow a normal distribution curve as the rate of change is gradual and cumulative |
What will happen if two populations of a species become geographically separated? | If two populations of a species become geographically separated then they will likely experience different ecological conditions. Over time, the two populations will adapt to the different environmental conditions and gradually diverge from one another |
What will the degree of divergence of the two species depend on? | The degree of divergence will depend on the extent of geographical separation and the amount of time since separation occurred |
What populations show less divergence? | Populations located in close proximity that separated recently will show less variation (less divergence) |
What populations show more divergence? | Distant populations that separated a longer period of time ago will show more variation (more divergence) |
What will the degree of divergence increase alongside? | The degree of divergence between geographically separated populations will gradually increase the longer they are separated |
What decreases alongside an increase in divergence? | As the genetic divergence between the related populations increase, their genetic compatibility consequently decreases |
To what extent can species diverge? | Eventually, the two populations will diverge to an extent where they can no longer interbreed if returned to a shared environment |
When are two species considered to be separate? | When two populations can no longer interbreed and produce fertile, viable offspring they are considered to be separate species |
What is speciation? | The evolutionary process by which two related populations diverge into separate species is called speciation |
In what two forms do peppered moths exist? | Peppered moths (Biston betularia) exist in two distinct polymorphic forms – a light colouration and a darker melanic variant |
What type of moth is predominant with low pollution? | In an unpolluted environment, the trees are covered by a pale-coloured lichen, which provides camouflage for the lighter moth |
What type of moth is predominant with high pollution? | In a polluted environment, sulphur dioxide kills the lichen while soot blackens the bark, providing camouflage for the dark moth |
What is the frequency of the two different forms of the moth dependent upon? | The frequency of the two different forms of peppered moth is dependent on the environment and evolves as conditions change |
What moth was predominant before the industrial evolution? | Before the industrial revolution, the environment was largely unpolluted and the lighter moth had a survival advantage |
What moth was predominant after the industrial evolution? | Following the industrial revolution, the environment became heavily polluted, conferring a survival advantage to the darker moth |
What is causing the frequency of the variations of the peppered moth to differ in modern days? | Recent environmental policies in Europe are reducing pollution levels, altering the frequency of the two populations once again |