Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > M7 Evolution, Speciation and Ecosystems > Flashcards

M7 Evolution, Speciation and Ecosystems Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Name the 3 types of selection.

A

Directional, Stabalising and Disruptive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe disruptive selection. Why is it important in the process of evolution?

A

Mean selected against, both extremes selected for. Could lead to two seperate species.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is differential reproductive success?

A

Difference between individuals in a given generation and how many offspring they are able to leave.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name the two types of speciation. What type of isolation are they?

A

Sympatric Speciation - reproductive isolation
(same place)

Allopatric Speciation - geographical isolation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What factors cause sympatric speciation?

A

Ecological - different habitats in same area

Temporal - incompatible breeding seasons

Behavioural - changes in behaviour

Mechanical - incompatible genitalia

Gametic - gametes prevented from meeting (e.g. pollen)

Hybrid sterility

Every Time Bees Make Gametes - Hybrid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does allopatric speciation occur?

A

There is genetic variation within any breeding population.

Populations of a species can become isolated stopping GENE FLOW.

New alleles produced by mutation (random).

These seperate populations are subjected to different selection pressures (e.g. enviornment) and so different alleles are beneficial and become more frequent in the population.

Over time GENE POOLS may become so different that if put together once more, individuals can no longer interbreed to produce fertile offspring (new species).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give examples of selection pressures

A
  • Climate conditions
  • Light intensity
  • Water availability
  • Food availbility
  • Disease
  • Predation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is adaptive radiation?

A

If a population becomes divided and each division is subjected to different selection pressures, their gene pools will diverge so that the phenotypes are adapted to each of the new environments - each may form a different species so that when reintroduced, members of different populations can no longer interbreed successfully.

(Imagine orgininal species radiating out to lots of different new adapted species)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is genetic drift?

A

The RANDOM changes in the frequency of alleles in a gene pool - usually small populations.

Smaller populations are more affected by any change in allele frequency (as greater proportion) and so more likely to develop into a new species. They also have lower genetic diversity and as there are fewer alleles, they will have unequal chances of being passed on.

Chance death or migration will also lead to genetic drift.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Any beneficial mutation that is selectively favoured in a small population will rapidly _____ in allele _______ and affect the whole population more _____.

In large populations, the effect of a mutant allele is more _____ and will take _____ to have a significant effect on allele _______.

A

increase
frequency
quickly

diluted
longer
frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define:
- Ecosystem
- Population
- Community
- Niche

A

ECOSYSTEM - interacting community of living organisms and their environment

POPULATION - all the organisms of the same species that live in the same place at the same time.

COMMUNITY - all the different populations of different species who live in the same place at the same time and interact with each other.

NICHE - The role of an organism in the ecosystem (e.g. nettle acts as a habitat and carries out photosynthesis, behaviours, where an organisms lives, what is eats, predators…)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Give examples of abiotic factors and how they are measured.

A

Temperature - thermometer
Light Intensity - light meter
pH of the envionment - pH meter
Moisture content of soil - heat-reweigh (another flashcard)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do you measure the water content of the soil?

A

1) Take a soil sample
2) Weigh
3) Heat and reweigh until constant mass reached
4) Loss of mass = moisture content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give examples of biotic factors.

A

Competition for resources
Food availability
Predation
Disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the carrying capacity?

A

The maximum stable population size that a particular environment can support over a long period of time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is inter vs intraspecific interaction?

A

INTER Interactions that occur between populations of different species vs INTRA within the same species/population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Other than predation and food availability, what else can be said to describe population-time graphs for 2 different species?

A
  • Predator numbers are always lower than prey numbers as there must be enough prey to reproduce and feed the predators.
  • Predators are generally larger and so take longer to reproduce so population increase is delayed and slower compared to prey.
  • Cyclic pattern as populations fluctuate.
18
Q

What is the main term for niche and name the two subcatagory niches?

A

Ecological niche:
- Fundamental niche
- Realised niche

19
Q

What is an ecological niche?

A

Total of an organism’s use of the resources in its environment.

20
Q

What is a fundamental niche?

A

The set of resources a population is theoretically capable of using.

21
Q

What is a realised niche?

A

The set of resources a population actually uses.

22
Q

What is the competitive exclusion principle?

A

When interspecific competition occurs for the same limited resources (as they have identical niches), one population will use the resources more EFFICIENTLY and gain a REPRODUCTIVE ADVANTAGE that will eventually eliminate the other from the habitat.

23
Q

What is resource partitioning?

A

Sympatric species tend to consume slightly different foods or use other resources in slightly different ways, allowing NICHE OVERLAP and therefore coexistence.

24
Q

What is a gene pool?

A

The total number of alleles in a population at a specific time.

25
Q

Describe the Mark-relase-recapture method.

What is the equation for estimating population size?

A

Catch animals of a particular species, count and mark (e.g. paint or tags). Release and leave to redistribute into the population. Second recapture. Total number caught and number of marked is recorded. Estimate population size.

N1 x N2 / Nm

26
Q

What are the 4 assumptions made during Mark-release-recapture?

A

The proportion n of marked to unmarked individuals in the second sample is the same as the as the proportion of marked to unmarked in the total population.

Marked individuals redistribute equally amongst the rest of the population.

No immigration or emigration (population has a boundary line).

Low number of births / deaths in population.

27
Q

What should be considered when marking animals in the Mark-Release-Recapture method?

A

DOESN’T CAUSE UNNATURAL DEATH:
Not toxic / Doesn’t make the individual more liable to predation.

MARK IS NOT RUBBED OFF/LOST

(To do with MATHS not ethics)

28
Q

What is succession?

A

The gradual directional change in a community of organisms over time.

(Plants change the abiotic factors allowing succession to occur)

29
Q

What is the difference between primary and secondary succession?

A

Primary: Original area has no soil/living organisms present (e.g. bare rock).

Secondary: Following disturbance of the area, soil is present.

30
Q

What can grow on bare rock and how can they survive? How does primary succession occur? Give a specific example.

A

Hostile environments - very few autotrophs survive (e.g. lichen and algae). They require wide dispersal mechanisms and tolerance to desiccation (little water) and low nutrients.

Lichens DISSOLVE the rock and when they die decomposers will break down their structures and start producing a rough soil allowing mosses to colonise. Mosses TRAP MOISTURE and shade lichens (so lichens die). Grasses with nitrogen-fixing bacteria in root nodules colonise next, increasing N-content of the soil when they die. Soil develops due to action of decomposers and larger plants can grow. When they die/their leaves shed, their nutrients can be recycled by detritivores.

31
Q

What are autotrophs?

A

Organisms that can produce its own food (organic compounds) from light, water and carbon dioxide (simple inorganic molecules).

32
Q

What is a climax community?

A

An ecological community in which populations of plants/animals remain stable. (size, species etc)

It is the final stage of succession and is usually identified by a dominant plant (usually woodland).

33
Q

Give examples of how human intervention can alter succession?

A

Clearing of deciduous woodland for agriculture, forestry and human settlement.

Intensive grazing by sheep.

Controlled and uncontrolled burning.

(all can deflect succession).

34
Q

What’s the term used to describe a deflected climax community?

A

Plagioclimax

35
Q

What are pioneer species? What do they do? What happens to them during succession?

A

The first species to populate a habitat.

They alter the environment and make it possible for a wider range of species to live there (e.g. Break down and release nutrients).

New species out-compete the previous (pioneer) species which die out. Over time the environment and community gradually changes until it reaches a climax community.

36
Q

What is conservation? What is it’s aim? What does it require?

A

Conservation is a method of maintaining ecosystems.

Aim: to maintain and increase biodiversity

It requires planning to make the best use of resources while preserving the natural landscape and wildlife.

37
Q

Ecosystems are ________ and e_____- c_______:
- e.g. 4000 years ago Britain was a climax community of oak woodland.
- e.g. burning of heather and grazing sheep maintains the moorland/heath habitats

A

Dynamic and ever-changing

38
Q

List some management strategies of conservation.

A
  • Raising carrying capacity (increase prey/space etc.)
  • Encourage dispersion of individuals (e.g. wildlife corridors)
  • Control predators
  • Vaccinate against disease
  • Preserve habitats (prevent pollution, intervene to restrict succession….)
39
Q

What are 4 reasons to conserve ecosystems?

A
  • Cultural and Aesthetic - enrich and inspire
  • Ethical - organisms have a right to survive
  • Economic (e.g. undiscovered medicines)
  • Personal (benefits the individual)

CEEP

40
Q

What is dynamic conservation?

A

Preservation of organisms / habitats that are at risk from human activity by improving what you already have - e.g. creation of new habitats. Requires proactive effort.

Dynamic conservation = IMPROVING what you’ve got.
Conservation = MAINTAINING what you’ve got.

Biology (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions