Darwin's Theory and Modern Genetics Darwin suggested that animals that live are the animals that mate, therefore pass on certain traits. Modern genetics say that breeding animals pass on certain chromosomes attached to certain traits, which give offspring certain qualities. Darwin’s theory and modern genetics are very similar and actually evolved unknowingly close to each other. Darwin’s theory led to five facts. First, “All species have such great potential fertility that their population size would increase exponentially if all individuals that are born reproduced successfully.” Second, “Most populations are normally stable in size, except for seaso