Biology Exam 7

Lamarck

Jean Baptiste Lamarck thought the more used traits became more dominant in offspring.

Like he would have thought that Giraffes had long necks because their ancestors stretched their necks to get the high fruits.

Hutton and Lyell

Lyell developed Hutton’s theories, together forming the concept of uniformitarianism, saying that the mechanisms of today are the same mechanisms from history.

Cuvier

Believed in catastrophism, that each boundary between strata of the Earth represented an ancient catastrophe.

Who advocates for catastrophism?

Uniformitarianism?

Catastrophism - Cuvier

Uniformitarianism - Lyell

Artificial Selection

Modification of species by selecting and breeding individuals with desired traits.

Natural Selection

Process by which individuals with certain inherited traits leave more offspring than individuals with other traits

What are the four evidence for evolution

1. Direct Observation

2. Fossil Record

3. Homology (similarities between species, ex: Similar forelimbs in vertebrates)

4. Biogeography (fossils line up on pangea)

Homologous Structures

Anatomical resemblances between species which come from a common ancestor

Analogous Structures

Anatomical resemblances in different species due to similar environmental pressures

Vestigial Structures

Structures which come from an ancestor but no longer serves a purpose

What are the three processes which change allele frequency (name don’t define)

Natural selection

Genetic drift

Gene flow

Genetic Drift

Definition

What is a possible outcome of genetic drift

Genetic drift describes how allele frequencies fluctuate unpredictably from generation to generation

Can result in a loss of variation as an allele might disappear from the population

Two types of genetic drift and what they mean

• Bottleneck

Something causes a large reduction in the population

• Founder Effect

A certain part of the population gets isolated from the larger population

Gene Flow

Definition

What is a possible outcome of genetic drift

Gene Flow describes the movement of alleles among populations (ex: pollen gets carried from one group of flowers to another)

This can result in less variation between populations as they end up becoming more homogenous with each other.

What are the five conditions for Hardy Weinberg equilibrium

1. Random mating

2. No natural selection

3. Extremely large population size

4. No gene flow

5. No mutations

Hardy-Weinberg Formulas

Chi-Square Formula

Standard Deviation Formula

Standard Error Formula

What are the sources of variation in a population?

1. Gene mutation

2. Crossing over

3. Independent Assortment

4. Fertilization

5. Change in chromosome number